Right Side Up: A History of the Space Transportation System

I look forward to seeing any images of the LTVs that get produced! I'm having a little trouble visualizing the stabilizing flare.
Some visualisation would be nice indeed! While the STS itself has been rendered, all the other wonderful designs are left unseen. The space stations, the Uragan system, Sierra, Hermes, and lastly the LTVs would make for some amazing renders, especially when combined into their various launch architectures.

As for the updates themselves, they are excellent, and I've been reading them right at the time they're posted, which makes for a good weekly routine. The creativity and the intelligence that went into crafting the various spacecrafts and their operational trajectories is simply amazing. My only point of criticism would be that there's not enough of it, since I could easily see Eyes Turned Skyward-levels of detail coming out of the broad premise of a well-done STS. But somehow the current structure is both detailed and concise, so I have nothing really to complain about. Well, okay, maybe one more thing, which is that the politics of the world follow OTL very closely, since the various presidential elections and the fall of the soviet union are two important factors in determining spaceflight's history. Surely messing around with these a little could make for a more interesting history. Then again, these divergences get out of hand quickly, especially when they're not the focus of the story.

Eager to see where it goes from here. My guess is that the TL cuts off in 2011, when OTL's STS ended, but this leaves plenty of room to see what happens after the upcoming lunar return. Keep up the good work!
Maybe I can help out a bit ;)

NASA's first two Lunar Transfer Vehicles, LTV-1 and LTV-2 (affectionately known as Siegfried and Roy), make a docked burn during their first test flight.

After several years in space boosting cargo to the Moon, a Lunar Transfer Vehicle is picked up by a space shuttle orbiter for return to Earth for refit.

Lastly, here's some video from an early aerobraking test (click to play):

These images are really cool! The tugs look quite elegant, even if the flare and the heatshield are a little unconventional. Makes for a good wallpaper ;)
Anyone else thinking back on e of pi's thread a few years ago about a Chinese space program based on adaption of a Gemini-modeled spacecraft and relatively small modules of similar scale (5 tonne and under) used to tinkertoy together various functional craft? The dual docking port design is what is so very unique--similar to modules used to make Mir or ISS in concept but those never involved major propulsion units to my knowledge.

Instead of cylinders with a flared skirt to shield the engine face during entry, I think I would have imagined either a wide conic shield (similar to imaginary extension of the flared skirt found here to a point within the cylinder and then scaled up) enclosing a very shallow but broad conic tank structure with the engine face being very broad. But how to launch such a thing? With sidesaddle mounting similar to the Shuttle's OTL, we could have the "Ninja Turtle" configuration I suppose and indeed I was thinking of proposals in the mid-80s OTL for a return to Lunar space based on Shuttle launches only, where such reusable aerobraking ferry-tugs were envisioned.

And a major difference is that I believe those tug modules were meant to aerobrake with a single pass, once down and done, an idea that e of pi has shot down many times. We have OTL experience of multi-pass aerobraking using structures little different from those designed for no entry ever except to destroy them, and as far as I know there has never been a successful skip-once entry to a stable orbit--closest to it would be the last Zond mission I suppose, which IIRC did successfully skip an entry capsule once off the atmosphere but instead of going into orbit sent it most of the way round for a final entry trajectory. I have of course always been thinking in terms of crewed vehicles, reusable ones being launched from a LEO station to a distant high energy one such as Lunar space or near interplanetary space, then using a single skip-brake to arrive in an orbit with apogee below the Van Allen belts which a small burn could stabilize into a parking orbit from which to maneuver into rendezvous with the same station that launched it. Multiple skips are no good for this because first of all the early orbits would have very long periods, days or weeks, and second they all go through the Van Allen belts.

We know these vehicles have been checked out for that passage of course.
So, after nearly 2000 F-1 engine starts (55 on Saturn Vs, and 230 missions each with 5 ground and 3 air starts), they finally have a turbopump failure. I guess that's what not building a bleeding edge engine and being able to inspect it regularly does.
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So, after nearly 2000 F-1 engine starts (55 on Saturn Vs, and 230 missions each with 5 ground and 3 air starts), they finally have a turbopump failure. I guess that's what not building a bleeding edge engine and being able to inspect it regularly does.

So what, SSME made 3171 engine starts and had during operational time NO turbopump failure, all seven incidents were do valve problems and errors in sensors let to RSLS shutdown and one case were cooling in nozzle was damage by lose pin during lift-off.
I wonder that F-1B got this kind of turbopump failure, i expected more a error in the sensors or valves, that let to premature shut down of engine...
So what, SSME made 3171 engine starts and had during operational time NO turbopump failure, all seven incidents were do valve problems and errors in sensors let to RSLS shutdown and one case were cooling in nozzle was damage by lose pin during lift-off.
I wonder that F-1B got this kind of turbopump failure, i expected more a error in the sensors or valves, that let to premature shut down of engine...
Considering the F engine family, which most certainly did take on a tremendous challenge in terms of generating massive thrust at sea level, is in other respects rather moderate in its ambitions, operating at a chamber pressure only incrementally higher than prior art like the H engines, and sticking to a well known propellant mix instead of going out on the limb of hydrogen pumping and combustion, it is odd that it should break down before the OTL SSME which pushed the envelope much farther, in terms of chamber pressure (thus requiring two stages of pump for both fuel and oxidant), staged combustion, and tackling the use of hydrogen fuel.

On the other side of it, to match the tremendous thrust of 5 F-1B engines would require a whole lot of SSMEs burning in parallel. I am not sure how much sheer raw thrust should matter in driving engine failures--surely if the engine can put out nearly 10 times the thrust of another type, its parts are also more robust by that same ratio. Anyway to get a comparable outcome on the ground one would have far more than 3 SSMEs installed in some ATL hydrogen fueled version of Lifter, which multiplies the chances of failure and reduces time to failure per set of launch numbers. Since by that comparison we just have not burned that many SSMEs for so many launches, we don't know just when one would suffer a turbopump failure. And the other failures, for reasons of malfunctioning sensors, would surely ground more ATL-Hydrogen-Lifter launches, since it only takes a "no go" warning however spurious from one engine to do that.
So what, SSME made 3171 engine starts and had during operational time NO turbopump failure, all seven incidents were do valve problems and errors in sensors let to RSLS shutdown and one case were cooling in nozzle was damage by lose pin during lift-off.
I wonder that F-1B got this kind of turbopump failure, i expected more a error in the sensors or valves, that let to premature shut down of engine...

The SSME had only about 450 flight starts of the kind that I was counting here (launchpad and in-air starts), which is about one fifth of what Lifter has done here.
Chapter 17: Approach
So due to a severe oversight on my part, I posted next week's chapter this week and didn't notice the mistake until e of pi pointed it out to me...:oops:...Well, lucky you guys! You get two chapters this week!

“On Apollo 8, we were so close. Just 60 nautical miles down, and it was as if I could just step out, and walk on the face of it.”​

Chapter 17: Approach

Constitution soared down the Florida coast, tracing the beaches, guided by radio signals from Kennedy Space Center. Strictly speaking, the guidance was not needed--two veteran naval aviators like Young and Crippen could have navigated along that familiar coast in their sleep--but why fly without it?

The spacecraft had by this point completed her metamorphosis into a colossal aircraft. Her rocket propellant tanks were almost entirely empty. Only a small slick of kerosene remained on one wall of the RP-1 tank. The LOX tank had already been vented into the atmosphere. Her F-1Bs were silent and would not light up again on this flight. Safely hidden from the incoming air stream by protective fairings, they had little influence on her aerodynamics. Her ten F-110 jet engines provided all of her propulsion now, burning a separate supply of JP-8 jet fuel, running at a fairly low throttle. Her peroxide thrusters were almost useless in the thick troposphere, and instead she relied on her vast sail-like control surfaces, whose internal hydraulic rigging kept her course steady and mostly level. She was now moving at a subsonic, but still respectable, pace, matching that of any airliner.

She still handled sluggishly. Her pedigree was a spotty one, for rockets, ultimately, are a form of artillery, not aircraft. Her family’s rebirth as rocket-propelled aircraft was a matter of cost optimization, not of performance optimization, and it showed in her maneuverability, or rather, lack thereof. The task of bringing
Constitution to a safe landing had far more in common with that of landing a Boeing 747 than a fighter jet.

The craft was immense, but mostly empty. Her sail area was large, her inertia small. She responded with sudden jolts to any unexpected turbulence. Young and Crippen held her steady with hands honed in conditions far tougher. They had no time, busy as they were with the constant checking and re-checking of the aircraft’s displays and dials, to reflect on the increasingly mundane character of her flight, as a ship capable of hypersonic flight at the very edge of space came to imitate her mundane cousins who plied the routes between airports.

While briefing the President on the progress of the LTV and Armstrong throughout 1994, Goldin was quick to stress the strides which were ongoing in both programs. By the fall of 1994, the Lunar Transfer Main Engine’s combustion problems had been almost entirely resolved, and Pratt & Whitney were delivering completed engines to McDonnell-Douglas for integration. Meanwhile, IBM had delivered the radiation-hardened instrumentation units that would guide the new stages through the Earth’s radiation belts to their needle-threading dives into the atmosphere. At the same time, Armstrong’s Equipment and Service Module had arrived at the Kennedy Space Center’s Payload Processing Facility, where engineers conducted fit tests between it and the modified S-IVD that would serve as Armstrong’s annex. Both of the programs that President Bush had signed into law were nearing completion. With their milestones came a need to chart the course for the next phase of the Space Exploration Initiative: the one which would select from among the myriad of possible applications for the hardware the shape of human spaceflight for the next decade. A decision for which George Bush had laid groundwork now lay in the hands of his successor.

The decision came as no particular shock to the White House: while stressing the progress of NASA’s projects, Administrator Goldin had repeatedly pointed out that the time had come for a new direction for spaceflight. He had also pointed out that the simplest, cheapest project to tie this elements together was that which had guided the original design of the LTV and the Hermes capsule. If unstated, the goal had always been manned lunar orbit and surface operations, as another president might have said, “before this decade is out.” While the hardware to access lunar orbit had been approved, no formal authorization had ever been made of an overarching architecture. With LTV on-track for a debut in late 1995, Goldin outlined the design studies NASA had done, but pointed out that the agency had not yet committed to the lander or a staging platform in lunar orbit. Goldin and Vice President Gore, between them, sold Clinton on the idea during 1994, and the program (dubbed the International Lunar Program, in recognition of the European, Japanese, and Russian contributions that helped make it possible and to avoid for the moment the challenge of finding a name that satisfied all parties) was officially funded for FY1995. Clinton’s motivations came down to a combination of politics and legacy; with the LTV to finish testing by the end of 1996, there was an incentive to throw funding toward the aerospace industry, particularly in the swing-state of Florida. As the economy recovered from the recession of the early 1990s, there was no serious opposition to the modest increase in spending necessary to develop the lander (whose hardware had a great deal in common with that of the LTVs) and its Low Lunar Orbit support station (essentially composed of spare parts from the existing LEO programs).

Clinton’s other motivation for supporting the lunar surface program came down to an appeal to his legacy and that of John F. Kennedy, the earlier Democrat whom Clinton had met in 1963. Clinton publicly credited that meeting, together with Martin Luther King Jr.’s “I have a Dream” speech, for inspiring him to go into politics, and the youthful image he cultivated consciously imitated the martyred statesman (as, sneered many Republicans, did his personal indiscretions). The American manned space program had become one of the programs most closely tied to Kennedy’s name (as it had been one of the few that went into effect before his murder), and a generation of news of launches from “Cape Kennedy” or the “Kennedy Space Center” had only strengthened the association in the public eye. Even though the actual Moon landings had taken place under President Nixon, and most historians would argue that President Johnson played a far greater role in creating Apollo, the public still viewed the Moon landing as Kennedy’s triumph. With the Lunar Transfer Vehicle already in testing, Clinton could reasonably expect a lunar landing by 2000, while he was still in office (assuming a victory in the 1996 election), enabling him to similarly create a legacy in space. Whoever followed him into office would have astronauts on the Moon executing Clinton’s program.

It was these considerations that led Clinton to announce, during his State of the Union address on January 24, 1995, "We are even now embarked on the path to the Moon. I have directed the National Air and Space Agency to continue down this road with a new lunar lander, building on the reusable legacy, not just to go to the moon, but to eventually stay."

The lunar surface exploration program called for two new vehicles: a man-tended outpost in a lunar polar orbit, which would use surplus Armstrong and Shuttle hardware and provide station-keeping, light servicing, and propellant-transfer facilities for the second vehicle, the lunar lander. The lander far outclassed the Apollo Lunar Module--designed to be fueled and serviced by three two-stage LTV missions to Low Lunar Orbit, it would have a wet mass of more than 25 metric tons tonnes and could deliver 8.5 tonnes of payload to the lunar surface and back. The new lander would be fully reusable, returning to a Low Lunar Orbit platform for use on a later mission or return to Earth by an LTV and either the Shuttle or some successor vehicle (though, given the cost of such a return, that kind of operation would be done only rarely).

The decision to develop a fully-reusable lander architecture with such an impressive payload capacity proves the truth of Mark Twain’s adage that “history doesn’t repeat itself but it often rhymes.” Though the official Apollo/Saturn program began winding down as early as 1967, when the development work for the space systems was virtually complete and a landing on the Moon (even if Kennedy’s deadline was missed) seemed a foregone conclusion, NASA’s official party line was that Apollo’s purpose was not limited to putting a man on the Moon. The Apollo and Saturn hardware, the agency insisted, would see ongoing use in earth-observing scientific missions, interplanetary robotic probes and human missions, missions to study solar physics, and ongoing missions to the Moon. Though the scope of the program was drastically cut back to support the development of the Space Lifter and Space Shuttle, the party line had, ultimately, mostly come true. Skylab had proven many of the concepts that would be required to develop Spacelab, Lifter-Centaur had lofted a multitude of unmanned probes that returned data on every element of the solar system and the greater universe, and the Shuttle had allowed the US and its European and Japanese allies to break new ground in microgravity science aboard Spacelab. Though NASA had turned its attention in the late 1970s toward using space rather than building the infrastructure to tap the unique possibilities beyond the Karman line, the Space Exploration Initiative marked a return to the old roadmap.

In accordance with the goal of establishing a sustainable infrastructure with which to explore the Moon and open possibilities beyond, the lunar landing system had to be reusable while still delivering a significant amount of payload to the lunar surface. Though NASA did not plan to do this regularly, the option of returning the lander to Earth for inspection was preferred. For many reasons (including storability, development cost, and propellant density), methane was the preferred fuel. Satisfying all of these requirements in a single craft in a single flight proved unfeasible, but the lander’s reusability meant that the payload issue could be addressed by simply landing twice--once to deliver surface cargo, and then again with crew. Mission planners soon converged on a two-landing architecture, in which the lander would deploy a payload, return to a small Low Lunar Orbit Platform, refuel, and then deliver the crew to meet that payload. The entire lunar transportation architecture would thus be reusable, except for launch vehicle upper stages for flights carrying crew, cargo, and propellant to LEO, and for the lunar surface laboratories and equipment pallets, which would be left behind on the Moon after each mission, forming a gradually-expanding network of functioning habitats and scientific experiment arrays that could be reactivated and revisited at any later moment.

Digging back to Apollo Applications Program designs for the Lunar Module Truck and Taxi, and to more recent design studies for lunar surface habitats and vehicles, engineers at the Johnson Space Center converged on two possible target payloads--11.5 tonnes (which would require two LTV supply flights per landing) and 21 tonnes (which would require three). The spacecraft that would carry those payloads down would be a 4.5-tonne (dry) assembly of propellant tanks and landing legs wrapped around a single, throttleable LTME. With the spacecraft’s design converged upon, the last serious debate as JSC was exactly how capable it should be. 11.5 tonnes of payload per crewed mission was enough for up to a week, maybe two, of human exploration, whereas 21 tonnes opened up the possibility for month-long (or even longer) flights. More conservative engineers favored the smaller design, believing it to be easier to develop, cheaper to operate, and an easier sale to the politicians who ultimately controlled NASA’s budget. Opposing them was a faction committed to the idea of LSAV as a heavy cargo carrier that would open the Moon to American interests as effectively as Lifter had opened LEO and GEO. Pointing to the earlier vehicle’s success, they noted that Lifter’s immense capacity, while greater than many of its payloads really needed, had given NASA the capability to conduct those few great missions that could make full use of its power, like Spacelab, the unmanned probes to the outer planets, and the Shuttle missions. That capability had allowed Lifter to operate for nearly twenty years, to the point where its immense lift capacity had become the cornerstone of NASA’s and McDonnell-Douglas’s plans to refuel and operate the LTVs. “Build it, and they will come,” went the thinking. “In the void of space,” argued one engineer at a team meeting in Houston, “vehicles are infrastructure, and we’re building the Interstate to the Moon.”

The more ambitious faction eventually won out at JSC, and it was their design, a lander with a wet mass of 46 tonnes, of which up to 21 tonnes was payload to the lunar surface, that went to President Clinton’s desk. Following a briefing from NASA Administrator Dan Goldin, Clinton gave his formal blessing to the 46-tonne Lunar Surface Access Vehicle, which would become the most visible vehicle of the Space Exploration Initiative.

As it turned out, the decision to adopt a high-payload lander design would impact the entire world’s aerospace industry. The lunar surface exploration program outlined in 1995 (which would become known as the International Lunar Program) called for two lunar surface missions per year. These missions would each require three flights of a two-stage LTV, which added up to an initial mass in Low Earth Orbit (IMLEO) of over 250 tonnes per mission! Given that at least one Lifter flight per lunar mission had to loft the Shuttle containing the crew for that mission, the program would require over a dozen Lifter flights per year on its own. Between the ILP, crew rotation missions to Armstrong, and Lifter’s existing unmanned payload manifest, the Space Transportation System would have been taxed to its limits (and with the Lifters growing long in the tooth after over 15 years of frequent service, neither Boeing nor the Space Transportation Corporation wanted to push their luck with a ramped-up flight rate). The Commercial Propellant Supply Services contract, which had originated as an effort to secure redundancy for LTV propellant supplies, had gone from a luxury to a necessity, as alternative launchers were needed to supplement the Space Transportation System.

Of the alternative launchers available in 1995, only the Russian Raskat-Groza system and the TPLI Sierra (still in testing) had the capacity to supplement Lifter. Ariane was too small, and the European Space Agency’s launch complex in French Guiana was not optimized for the frequent flights it would need to make up for that shortcoming. The Clinton Administration and NASA quickly found a silver lining in the cloud of limited launch capacity: as Russia’s economic and geopolitical situation deteriorated and the structural failures of the Soviet Union grew ever more apparent (with an HIV/AIDS epidemic that dwarfed that which had terrified Reagan’s America, and the emergence of sinister new narcotics in a booming Russian market), a launch services contract to NPO Energiya seemed, to the State Department, more an instrument of humanitarian relief than a frivolous expenditure. Every light that stayed on in Moscow, Baikonur, and Kazan was a household that had not turned to prostitution or Krokodil to avoid starvation.

Two Commercial Propellant Supply Services contracts were awarded in 1996, each for 800 tonnes of propellant delivered to Lunar Transfer Vehicles between 1997 and 2002, to NPO-Energiya and Trans-Pacific Launch Industries. Though this amounted to only about four flights per year of Raskat-Groza and six to seven per year of Sierra, it was a significant boost to the Russian annual flight rate, and helped speed along the Russification of the Raskat boosters, a process which accelerated significantly when Russia’s new Prime Minister, Vladimir Putin, took power. It was also a massive boon to TPLI: coming swiftly on the heels of Sierra’s first successful orbital test flight, it greatly increased customer confidence in the new consortium, and initiated a rapid expansion of TPLI’s customer base from a handful of low-orbiting communications constellations to a much more diverse set of payloads and destinations.

Though the ground on which the new spacecraft tread (literally, in the lander’s case) was now far better known than it had been in the 1960s, the development of the new spacecraft was still an impressive and lucrative contract for which the American aerospace industry’s remaining prime contractors marshalled their formidable resources. The sharp contraction of the American aerospace industry since 1991 reduced the total number of bids, but each of the surviving companies combined the best talent from their acquisitions, leading to a bidding process as heated as any before it.

Ultimately, NASA awarded the Low Lunar Orbit Platform (LLOP) contract to a joint bid from Grumman Aerospace and Hughes Satellite Systems, a choice that seems surprising (between Grumman’s near-insolvency and Hughes’ inexperience with manned systems) until one considers the LLOP’s unique mission. Unlike Spacelab or Armstrong, the LLOP was not a laboratory or a full-time human habitat. Its power and thermal requirements were considerably less demanding than those of the Low Earth Orbit space stations, and were well within the capabilities of Hughes’ communication satellites. The pressurized part of the LLOP was heavily derived from Grumman’s MPEM (though it did not share a pressure vessel, as the requirement for a radial docking port precluded that possibility), and most of the subsystems could be reused from that with minimal modification. Hughes and Grumman, while not the largest competitors, were the smartest choices in 1996. The sale of Grumman Space Systems to Martin Marietta did not change that reality (and caused very little disruption to the program).

Though LLOP was a welcome victory for Grumman and Hughes, it was not the main prize in 1995. The Lunar Surface Access Vehicle (LSAV), the gargantuan reusable lunar lander, was the more prestigious of the two projects. Though its propulsion systems had already been specified to use the same methane-oxygen systems developed for the LTV (including the Lunar Transfer Main Engine), the structure, avionics, thermal and power systems, and final assembly remained up for grabs. Though Grumman and Hughes made a bid for the lander as well, it was a far greater task than LLOP, and the small consortium was never really in the running. Rather, the contract soon came down to a three-way race between Boeing, McDonnell-Douglas, and Martin Marietta. Each company had its own strengths and weaknesses--Boeing had the strongest record in actual spacecraft construction, though McDonnell-Douglas had gained some ground in that field with the LTV program and would have had the least difficulty integrating the propulsion system, and Martin-Marietta was the undisputed world leader in autonomous vertical landing technology. The competition to secure the LSAV contract was a tight one indeed, and the budding space news sector on the internet swarmed with contradictory rumors for months leading up to the final announcement. Ultimately, in a surprise coup, Martin-Marietta secured the contract, as the company’s proposal was highly rated on both its organizational and technical strengths. Based on some hardware from the Fuji upper stage, the LSAV’s landing systems would be very closely derived from the vertical-landing hardware and software that Martin-Marietta had been perfecting since the 1980s. Though the propulsion system would remain a McDonnell-Douglas subcontract, Martin-Marietta’s interest in perfecting low-boil-off (LBO) and zero-boil-off (ZBO) LH2 storage hinted at the possibility of a future generation lander that would use cryogenic hydrogen to massively increase payload to the Moon.

The LSAV contract could not come swiftly enough for Martin-Marietta, which was still struggling in the aftereffects of the Japanese asset bubble on their Trans-Pacific Launch Industries partnership with Mitsubishi and the Japanese government. Martin-Marietta’s fortunes recovered somewhat as the general American economy recovered from the recession of 1991, but increasingly Sierra became a make-or-break project for the company. Its continued survival would stand or fall on TPLI’s successful entry into the commercial launch market.

In many respects, the LSAV contract marked the last great hurrah for the traditional aerospace contractors of the US. While the contract itself was small compared to the great defense contracts that had filled their coffers during the Cold War, it was the last time that these companies, some of which had been independent since before the Second World War, could make a bid to be prime contractors on a new aerospace vehicle. Following McDonnell-Douglas’s and Pratt & Whitney’s success, the strains of Peace Dividend budget cuts combined with overseas competition and, in some cases, poor management decisions finally caught up to many of their competitors, initiating a rapid succession of mergers, consolidations, and divestments that would leave the American aerospace sector in the hands of a much smaller number of prime contractors.

The process had already begun in the early 1970s, with the cancellation of the Lockheed 1011 TriStar jet airliner program. Long-delayed due to engine availability issues, it was finally scrapped when the interested airlines committed instead to Douglas’s DC-10 (known as the MD-10 in later production runs, after the merger with McDonnell), and Lockheed permanently dropped out of the civil airliner market, which, in the US, was split between Boeing and McDonnell-Douglas. Lockheed refocused on military aircraft, perfecting cutting-edge stealth technology, which made its debut in the form of the F-117 Nighthawk. Lockheed followed up its success with the B-2 Ghost, an even stealthier high-altitude bomber design, becoming the undisputed world leader in stealth technology. Alas, with the cancellation of most B-2 orders following the Soviet Union’s demise, Lockheed could not soldier on alone, and was bought out by its old airliner rival, McDonnell-Douglas, which attempted to leverage its own supremacy in naval aviation with Lockheed’s stealth technology for the A-12 Avenger II project (which, unfortunately for the conglomerate, went nowhere).

Lockheed was not the only company swallowed by McDonnell-Douglas. Grumman Aerospace had once enjoyed the confidence of the US Navy’s top admirals and of NASA’s astronauts, and its engineers had blazed many new trails that other companies would profitably exploit. However, from the early 1980s, the aeronautical section of the company had increasingly been deemphasized, as managers gave up hope of winning new prime contracts. Electronic subsystems instead were emphasized, as the company adapted to the new age of electronic warfare. It was this section of the company that would eventually be purchased by McDonnell-Douglas in 1997, leaving Grumman Space Systems to soldier on a very short while longer before it, and all its R&D contracts, and the MPEM (its last prime contract from NASA) were acquired by Martin-Marietta.

Northrop Corporation was badly burned by a series of ill-fated partnerships in the 1970s and 1980s, which left the company with a great deal of patents and research it could leverage for future planes but no actual prime contract to provide income. The partnership with McDonnell-Douglas had given the latter the F/A-18 Hornet carrier-based fighter, and was supposed to give Northrop an F-18L to sell on the export market. However, McDonnell-Douglas began selling an export-variant of the F/A-18, cutting Northrop out of the market and securing all the profit on Northrop’s significant research investment (going back to the YF-17). Soured on working with McDonnell-Douglas, Northrop instead partnered with Boeing to bid on the aircraft that eventually became the B-2 Spirit. While Northrop’s approach was, in many respects, more innovative and capable than Lockheed’s, the company’s pure flying-wing proposal would not win that competition. Boeing fell back on its bomber, airliner, and spacecraft businesses, but Northrop did not have this option. The company would eventually be bought by Martin-Marietta for a very low price, in a deal brokered by the US Department of Commerce and Department of Defense to prevent McDonnell-Douglas from getting an undisputed monopoly on stealth technology, and as part of an effort by Martin-Marietta to maintain any business outside of their launch services division.

Martin-Marietta, by the 1990s, had become almost entirely focused on rocket technology. Through its work on vertical-landing demonstrators for the US Department of Defense and its partnership with Mitsubishi in TPLI, it had made great strides in perfecting reusable, ballistic vehicles. It was also one of the US’s premier ICBM manufacturers, involved in the LGM-118 Peacekeeper and the MGM-134 “Midgetman” missile programs. Unfortunately, the end of the USSR marked a drastic reduction in funding for new missiles--the MGM-134 program was cancelled in 1991, after only one prototype missile was built and tested in 1989. The cancellation left Martin-Marietta an extremely narrowly-focused company--one whose main business had become civil space transport. It could continue to fund the development of Sierra through infusions of cash from investors (including its partner, Mitsubishi Heavy Industries), but its investors worried about the possibility of the entire company going under if Sierra and TPLI proved a bust. When Northrop became available at a fantastically low price, Martin-Marietta’s board jumped at the possibility of entering what had been the lucrative military aviation market. As it turned out, the merger essentially produced two parallel firms under a single name, and the fortunes of one did not severely impact the fortunes of the other.

By early 1995, Sierra’s development work had been completed. The first stage had completed its first trial firings and demonstration flights in Japan, under the authority of Mitsubishi Heavy Industry the year before. Meanwhile, the first Martin-built Fuji orbiter stage was transferred to the White Sands Missile Test Range for the integrated vehicle’s first shakedown flights. Flying first with partial fuel loads on only its LE-5 landing engines, then with increasing propellant loads and payload mass simulators, Martin put Fuji through its paces, demonstrating the vertical landing techniques Martin-Marietta had first demonstrated in the 1980s. At the first and second stage test sites and the launch-sites-to-be in Japan and the United States, TPLI’s launch technicians trained for all possible pre-launch eventualities. After successfully completing its suborbital flight test program, the first flight Fuji stage was shipped to Vandenberg Air Force Base, where it met with the Mitsubishi-built Sierra lower stage before the combined stack moved to the former Titan II launch pad at SLC-4W.

Though Sierra appeared to be on-track for a debut by early 1996, Martin-Marietta’s executives had become nervous about the company’s near-total lack of revenue until that time. As Sierra development work concluded and the project moved into fabrication and testing, they sought ways to make their vast pool of intellectual capital turn a more immediate profit. The LSAV contract was the clearest way to do that. Banking on their reputation for success in vertical landings, and on the fact that the company had recently built a new spacecraft from scratch without running too far over their planned schedule and budget, Martin-Marietta submitted its bid in the hope of securing a revenue stream that could pad the company out if Trans-Pacific Launch Industries turned out to be a bust. To the delight of its shareholders, it succeeded. The infusion of NASA capital into Martin-Marietta’s coffers helped insulate the company against the potential consequences of a Sierra delay.

While the American contractors popped champagne corks in celebration of winning the prestigious new vehicles, their European counterparts were hard at work rating the Hermes capsules for lunar operations. In close cooperation with their counterparts at McDonnell-Douglas and the Johnson Space Center, Airbus engineers conducted fit tests and developed the hardware necessary to transfer power and cooling fluid between the crewed capsule and the LTV it would ride to lunar orbit. Though the spacecraft milestones were steadily checked-off, the first LTV-adapted Hermes was not ready to join the first LTVs on their 1996 orbital demo flight, due to a distressing incident when an oxygen resupply hose (meant to tap off some of the LTV’s residual oxidizer as a supplement to the capsule’s breathable air) exploded during testing due to a mistaken conversion between kilopascals and pounds-per-square-inch, forcing a systematic reevaluation of the eCRV’s compatibility with American-built hardware (for its part, McDonnell-Douglas responded by publishing SI guides and manuals for its hardware).

As the Clinton administration made its decisions on how to exert their influence on US and global space policy, the existing LTV program continued pushing onward. The first completed LTV boilerplate was shipped from McDonnell’s plants for testing in the Plum Brook Station vacuum chamber at the Glenn Research Center in Ohio in August of 1994 for testing of the spacecraft’s actuators and tank performance vacuum. A key point was the ability of the system to reflect heat and prevent it from reaching the cryogenic propellants inside, reducing boil off and enhancing system life. It was anticipated that the same thermal insulation designed to resist the fires of entry could serve to reduce boil off, and indeed the incredibly low boiloff rates realized demonstrated the additional wisdom wisdom of the decision to go with soft cryogens for the LTV, one originally forced by density and assembly complexity concerns. However, it proved to be vacuum actuators which would dog the program.

The LTV featured a complex arrangement of telescoping docking ports, a retracting nose heatshield cover, and an extendable and retractable solar array, which needed to survive extended periods in space during both the extreme heat of braking passes and the extreme cold of orbital night. The failure of even one actuator system and its backups to perform could lock the vehicle in a condition which made it unable to return to LEO, unable to power itself, or unable to dock for boost, fueling, and recovery. The actuating solar array proved the most difficult, with a tendency for the initial design to become jammed after extended cycling of heat and cold in vacuum conditions which had not manifested in early component testing. Re-evaluation of the test actuators on the boilerplate revealed a change in the bearings used in the actuator made after the initial proof tests, intended to reduce weight and increase design life, was actually impairing the function of the system. A switch back to the original design was quickly implemented, and testing at Plum Brook continued even as the second boilerplate awaited the arrival of its engine set from Pratt for test firings at NASA Stennis.

The Lunar Transfer Main Engine had also had its share of teething problems. The small size of the engine meant that runaway combustion instability had very little space to work, and the engine proved reliable and consistent...once lit. The challenges of the LTME's expander-cycle dependence on engine heat for pump power and the ignition in space of a mixture which was relatively new compared to the proven kerosene/LOX or hydrogen/LOX of the F-1 and J-2 engines made those initial seconds the most challenging in the engine's operation. Increasing propellant flow too slowly starved the engine of coolant, while increasing too quickly lead to several LTME prototype chambers suffering hard starts similar to those of the J-2S-2 on STS-116. The proper balancing of flow, pressure, and pump speeds in these critical moments took repeated testing of the spool-up from head-pressure idle to ignition to full-thrust that required months by themself. The testing had to be done, however, to qualify the ignition transients in temperature and pressure to ensure the LTME would light reliably and consistently, the first time or the hundredth. This long life was also a complicating factor: though the expander cycle was relatively low-stress compared to higher temperature cycles, the LTME needed a lifespan measured in dozens of missions. Once margins were included, that lead to a requirement for testing for more than 100 starts per test engine, with burn times exceeding 25,000 seconds of life per engine. This lead to additional focus on the engine's pumps, turbines, bearings, valves, and seals. Even once the ignition transient was conquered in mid-1994, testing continued on a near-weekly basis at NASA Stennis on LTME test engines to build the required lifespan data.

By late 1994, the LTME was judged mature enough to proceed to integrated testing, and the first full test set of four engines was qualified at Stennis, then shipped by air to McDonnell's assembly site to be assembled to the waiting set of boilerplate LTV tanks. For the first time, a complete LTV propulsion system was assembled, and the resulting Main Propulsion Test Article was shipped back to Stennis for testing of the engines together. Firings of the MPTA proved the effects of igniting all four engines together, the vibration modes of the integrated engines and tanks, and the effects of lighting only two engines at low throttle on the bells and chambers of the surrounding engines. With the completion of the MPTA tests and the final long-life engine tests, the LTV and the LTME had been proved in vacuum and as an integrated stage. The final proof was to see if the LTV could fly as a spacecraft on orbit. This task would fall to the next sets of tanks and engines off the line, integrated and designated as LTV-1 and LTV-2.

The LTV-1 and LTV-2 vehicles were entrusted with one of the most ambitious and complex missions ever attempted in NASA history, one as pioneering and controlled as any outer planets probe and as intensively and rigorously scheduled and monitored as a manned Space Shuttle flight. Comparisons to the engineering-packed but little-remembered Apollo 9 mission were common, but if anything the LTV demonstration was more complex. The official mission calendar assembled by McDonnell and NASA engineers from Marshall and Johnson included no fewer than half a dozen mission-critical technologies which would see their first demonstration on the flight, a dozen docking maneuvers, the first firings of the LTME in space, the first full demonstrations of cryogenic propellant transfer in microgravity, and the first demonstrations of autonomous multipass aerobraking for large spacecraft in seven deceleration series totaling more than one hundred individual atmospheric passes. During one planning session for the mission, a group of NASA engineers who had used the occasion of a weekend in the Los Angeles area to drive to Las Vegas between weeks of meetings groused that if they could pull the mission off, it'd be a trick better than that they'd seen pulled off by the magicians Siegfried and Roy. For the rest of the day, the names were tossed around to differentiate between the flight plans for LTV-1 and LTV-2 in the complex schedule, and the callsigns stuck.

The plan’s ambition was the result of the decision to test as much as possible with as few missions as possible, launching two LTVs fully fueled on the same Space Lifter. Once launched, the plan was to simply run down the demonstration checklist one at a time until issues were encountered or the mission was complete. Because of the tremendous capacity of the LTV, their delta-v unladen was impressive enough to allow the two vehicles, alone, to test every major element which would need proving out, assuming they held together. Alternate plans were considered in which short-fueled single LTVs would be flown inside the Space Shuttle, flown for incremental tests, then brought back down by Shuttle, but concerns arose over the cost and schedule of depending on multiple manned missions for the tests, and on flying crew to orbit with tons of sealed and volatile propellants on board, with no allowances made for venting in the case of a launch abort. Flying two vehicles on Lifter was ambitious, but it was also faster, better, and cheaper for testing than alternatives--magic words in the world of Administrator Goldin, who gave the plan his personal go-ahead.

LTV-1 and -2 were tested in the height of summer at NASA Stennis, then shipped for final integration with radar and communications dishes and their launch adapter truss at Kennedy Space Center. Though plans were underway for a student competition to name the tugs, those names would not be officially assigned until their triumphant recovery at the end of the mission. For the moment, the nicknames created by frustrated engineers in a Seal Beach conference room had stuck, and the names "Siegfried" and "Roy" for LTV-1 and -2 respectively were in common use by engineers and mission planners. Thanks to a herculean effort by Public Affairs, the names had so far avoided use in any official documentation. Still, as the pair prepared for launch aboard the Space Lifter Constitution, many in the office responsible for sorting through competition entries to determine and official name figured it was probably only a matter of time before the unofficial ones slipped into press coverage.

For all the worries about callsigns, aerobraking, the debut of the LTME, and the lifespan of the LTV in space, the biggest moment of terror in the Lunar Transfer Vehicle demonstration mission came during ascent aboard STS-240, launched on October 31, 1995. At just over a minute into ascent, while Siegfried and Roy were still inert inside their launch adapter and fairing, Constitution’s #3 engine telemetry began surging alarmingly. With pressure oscillating wildly inside the chamber, the automatic software shut the engine down, and began to throttle up the other four engines to compensate. As commander James Weatherbee and pilot Eileen Collins worked through checklists to complete the shutdown and confirm the throttle-up, Houston controllers worked through the implications and assessed the other engines. To all inspection, the data from the other four engines looked healthy, and none wanted a repeat of the Magellan accident with a critical payload arcing into the sea. However, there was still almost a minute left before staging and pushing on with multiple engines out could mean something worse: the loss of the booster, and possibly the crew, should there be any issues with the deployment of their cockpit entry pod.

These were unprecedented but not unanticipated decisions. With the loss of an entire F-1B engine, the STS-240 controllers immediately went from a routine mission into deciding which of innumerable contingencies, exhaustively modeled flight profiles, and extensively simulated procedures applied. At more than a minute into the flight, the Space Lifter had sufficient reserve thrust that it could still make the nominal flight profile even with one engine out by running the others longer before main engine cutoff--the so-called "press to MECO" option. The next-best option was an "abort to orbit," pushing to separation on the remaining engines, aiming to leave the payload in some orbit, if not the intended one. If that couldn't be managed, it might be all the crew could do to jettison of the unfired upper stage and payload and return to Kennedy. The last, worst case option would be if the engine's failure had damaged the stage's structure, and might mandate the first ever manned use of the Lifter's ejection pod to pull the crew to safety as the booster failed. The booster controllers scrambled to review their data and pre-analyzed procedures to determine which contingency applied. The decision was rendered more fraught by the speed with which engine #3 failed: the Lifter had gone from five healthy engines to four in less than five seconds. Could the remaining massive engines be trusted? Quick but intense debate followed between the Flight Dynamics Officer and the three Booster operators. As the Flight Director weighed the decision, Weatherbee and Collins called down their own encouragement. "Houston, CDR. Number three out, but pilot say all others are solid. Are we go through MECO?" From the back of the line of consoles, the Flight Director could see as the Flight Dynamics Officer nodded to herself emphatically and the booster controllers exchanged a look. He made the call. "CapCom, tell them go to press to MECO. Flight Dynamics, get working updated retro procedures."

The decision crackled up to Weatherbee's headset, and the crew set up the most optimistic of contingencies they'd hoped to never need. With the decision made to trust the remaining four F-1Bs, engineers hunched over consoles, as if by being closer to the screens they could get the telemetry slightly faster or wring just a bit more meaning from the data on their screens. Even the usual marker of main engine shutdown and a successful ignition of the S-IVD didn't bring relief. It was only after the required three F-1 engines relit and held through the retro burn that tension truly began to abate. The burnout of the S-IVD at an orbit several kilometers outside Lifter's usual delivery accuracy was only noted for later work. As their tasks on the main ascent finished, controllers paused, waiting for the updates as Constitution descended back to Florida. The appearance of the giant winged Lifter on the tracking cameras brought scattered whispers, then the touchdown of all three landing gear brought cheers to a degree rare among controllers in a program with more than 200 nominal landings under their belts. As Constitution rolled out along the Spacecraft Landing Facility's runway, scoring damage to the #3 engine fairing could be clearly seen, and investigators converged as soon as she came to a rest and the crew were extracted.
Chapter 18: Chasing
“If you can walk away from a landing, it's a good landing. If you use the airplane the next day, it's an outstanding landing.”​

Chapter 18: Chasing

Like a newborn whale swimming after its mother, the T-38 chase planes rose to meet Constitution as she descended toward Cape Canaveral. By now, the Lifter was cruising almost placidly, subsonically down the coast, well within the Talons’ ability to match its speed. The two Talons met it, trailing it, one to port, one to starboard, each with a clear view of the Lifter from the edges of its engine bells to its bulbous, hollow nose. Cameras in each airplane span through their film, capturing the Lifter’s descent over the scrub and ocean for posterity, and for inspection by engineers on the ground. The Lifter had made this descent several times before, but now she’d carried a new payload up, with new possibilities for failure, be they falling chunks of ice or simply different scorching patterns due to the unpredictable airflow around the Shuttle’s complex lifting surfaces--so they inspected her again, just in case.

The untrained eye would have lumped the two kinds of flying machine into the same class. Both bore delta-wings, allowing them to maneuver well above the speed of sound, and large rudders to manipulate the tenuous air high above Earth’s surface. The Talons, with their jet nozzles at their aft end, looked almost like juvenile Lifters, newly hatched, eventually to grow into mature space-planes. Even their paint schemes were not too dissimilar, each painted in the same glossy white, a NASA logo emblazoned on their flanks and tails. The black paint around the Talons’ cockpits, which protected their pilots from reflected glare, even matched the same marks painted into the coatings of the Lifter’s cockpit capsule for the same purpose.

But these similarities were barely more than skin-deep. The Talons were high-performance jet airplanes, essentially an engine with control surfaces attached, designed for the maximum possible aerodynamic performance. They could remain in the air far longer than the immense Lifter, which was nearly done with its jet propellant after a mere half-hour of flight, but they could never match its speed or altitude, or the terrific heat and pressure of atmospheric entry. The Lifter, by contrast, was by now, aerodynamically, a brick--her immense volume was mostly empty, and as she plunged into the thick troposphere she seemed scarcely more maneuverable than a submarine. Her 10 jet engines were enough to let her fly, but not to fly well. Her power lay instead in the five now-silent F-1Bs at her aft end, stained with soot and scorched from the monstrous heat they’d generated, which had sent her beyond the realm of aerodynamics altogether.

The Talons continued to tail their target, which had gone faster than they ever could and returned from a place forever beyond their reach. They could support her in these last moments of her mission, but, cosmetic similarities aside, they were fundamentally different creatures.

Until the moment that Constitution's landing gear touched the runway of the Spacecraft Landing Facility, the situation had struck observers as frighteningly similar to the loss of Magellan: a critical exploration payload at risk as a Lifter stack struggled to power past a major propulsion anomaly. News networks had stayed with the launch coverage longer than they usually did, and continued to check in as Constitution made her way back to Florida. However, with the booster safely landed and the payload inserted into a stable (if slightly off-target) orbit, the excitement faded quickly. NBC, CNN, and other networks carried the post-launch press conference live,, but the followup press conference the next day covering the beginnings of the investigation received less than a five minute story. With the payload on orbit, the crew safe, and the hardware already being torn down, there was less of a story. NASA and STC announced quickly that the issue had been a major failure of the turbopump of the #3 engine, but the details of the causes rapidly exceeded the interests of many news organizations short of Aviation Week. The question was what had caused the failure, how to resolve it, and how long it would take.

With direct access to the failed hardware, NASA, STC, and Rocketdyne were able to trace the root causes of the problem much faster than they could the Magellan failure. Instead of having to pore over the telemetry of a malfunctioning J-2S-2 and compare to engines in the same production batch, Rocketdyne and NASA were tearing down the very same engine which had failed while STC and NASA catalogued the effects in the surrounding engine compartment. The task was simple: catalog the smoke and char and the torn and twisted metal. The investigators could, in some cases quite literally, follow their noses to the problems’ sources. While industry engineers converged on the wounded booster at Cape Canaveral to evaluate damage and plan repairs, NASA investigators spread from Florida to production sites across the country to investigate the causes. The problems they’d find would determine how long it would take for Lifter to return to flight this time. Eager to divert attention to successes and with public interest in the near-incident falling off, NASA instead turned the focus of their public outreach to the new spacecraft Constitution had managed to launch.

The excitement of Constitution's engine-out ascent was remote 295 km above the Earth's surface, as the S-IVD fired separation pyros and Siegfried and Roy detached from the cradles of their launch adapter. Though lower than intended, the altitude of their resulting orbit was sufficient for weeks of orbital life, and the LTVs were--if they worked--nimble orbital maneuvering vehicles. As NASA engineers set to work investigating the causes of the ascent anomaly, another team began the process of opening the tug's heat shields, deploying their solar arrays, and checking communications, power, navigation, and radar systems. For two days, the two ships coasted in formation, briefly testing their thrusters and using each other as calibration targets for their rendezvous and docking radar. Finally, in their first major burn, both stages fired to adjust their orbital altitude to the originally-planned 400 km base orbit, then set to work on a series of docking tests. Under autonomous control, Siegfried and Roy took turns as the active and passive spacecraft, testing docking at both forward and aft ports under varying lighting and equipment conditions. One early approach, testing the procedures for a single-radar-out maneuver, failed when the active tug, Siegfried, began to register non-existent relative motion to Roy, and aborted automatically. The issue, caused by an erroneous routine attempting to parse data from the disabled radar to check the active one, was corrected by a software uplink and the remaining 10 docking attempts were all successful.

With the tug's orbital navigation and basic functions verified, it was time to confirm the function of the Lunar Transfer Main Engine in space for the first time. Roy loitered in the initial parking orbit, holding station, monitoring the measurable but tiny boil-off of methane and oxygen. While it marked time, LTV-2 repeatedly deployed and retracted its heat shield and solar charging systems to verify that the actuator issues encountered at Plum Brook were well and truly resolved. For its part, Siegfried lit its LTME cluster for its first extended burn of all engines, first with a small burn of a few hundred meters per second to check function, then, after a two-orbit pause to allow ground confirmation of the vehicle's onboard navigation, a larger burn which raised its perigee nearly to the Van Allen Belts. After a cross-check from the ground, Siegfried made one final burn, raising its apogee solidly into the lower Van Allen Belt. Siegfried lingered in the high energy flux for ten days, testing how the belt’s charged particles influenced its systems, and confirming that the radiation hardening installed would be sufficient for the nominal 5-day duration of a 30-pass aerobrake from lunar return trajectories. The boiloff from Roy was compared to Siegfried's tank pressures to determine how different heating and cooling cycles impacted the performance of the real LTV tanks on-orbit for comparison to ground data from Plum Brook.

Once this loitering period was complete, it was time for Siegfried to return to LEO. However, unlike its previous adjustments, this wouldn't be an entirely propulsive maneuver. The use of aerobraking for the LTV was critical to getting sufficient performance from a stage which could return in the Shuttle payload bay. However, to date the entire body of knowledge on aerobraking which did not result in immediate descent to a planet was the 1991 orbital adjustments of the MUSES-A spacecraft Hiten from Japan's Institute of Space and Astronomical Studies. In two passes in that year, the spacecraft had adjusted its lunar flyby orbits by skimming the upper reaches of Earth's atmosphere, shedding more than a kilometer per second of velocity to tailor its apogee height. This braking on a more-than-translunar trajectory was a remarkable achievement for a spacecraft protected not by insulation blankets, metallic heat shields, or ceramic tiles, but instead by foil sheeting and exposed solar array segments. However, while Hiten was a remarkable demonstration, and an achievement NASA and McDonnell had eagerly observed and offered some assistance analyzing, MUSES-A was barely two hundred kilograms, where the LTV would be fifteen times larger and would have to not simply skim the atmosphere, but dive deep into it in order to make its return to low Earth orbit. On its return to Earth from its initial Van Allen belt passes, Siegfried demonstrated its ability to carry out this braking by performing the last 250 m/s of braking purely aerodynamically.

As LTV-1 dove into the atmosphere, the mood in Houston's Mission Control Room was tense. This early in the demonstration mission, Siegfried was still ballasted with enough propellant to be more than three times heavier than it would be on return from a nominal flight. While the braking pass was relatively small compared to Hiten's attempts or passes planned later in the mission, the extra ballast would raise the stresses on the vehicle significantly, providing a test to prove the safety margins at nominal levels. In order to protect it from the heat of entry, LTV-1's main communications antenna was retracted within the aerodynamic flare. Telemetry would have to come from status tones passed at low bandwidth over smaller omni antennas and on what data could be collected from the ground. In order to maximize the data return, the pass was timed to take place in the early morning over the Eastern United States. A NASA P-3 Orion served as an airborne camera platform to record the pass visually, while military radars would track the spacecraft's position and velocity during the five minutes of peak heating. Siegfried carefully adjusted its perigee to skim the atmosphere at 95 kilometers--barely within the Von Karman line--then bored in on its entry trajectory. The pass was tense for engineers who had worked months and years to prepare for the mission, with more in common with a probe landing than a normal launch or a manned mission. There was nothing to do but watch the minimal telemetry which could come back on the secondary antenna, a simple condensed "attitude" and "temperature" return played alongside video from the Orion and radar tracking on the main screens. The minutes ticked past with agonizing slowness as Siegfried swept down the nominal trajectory.

Then, almost without noting, the perigee was past and Siegfried was rising once more. It was headed out of the atmosphere, but the question was how far above the atmosphere it would be after the adjustment. Finally, LTV-1 passed back over the Von Karman line and tracking radar confirmed than its apogee had been adjusted to within fifteen kilometers of the nominal planned distance. A pre-scheduled burn at apogee stabilized the perigee back above the atmosphere, then data began to be down-linked from the on-board recorders. Thermal data had been reported by dozens of thermocouples embedded in the backside of the heat-shield, sidewall insulation, and flare, as well as pressures and temperatures in the internal passages for circulating boiling methane as an active cooling system, and at carefully selected points on the outer skin of the LTV. Siegfried's armor had protected it, and LTV-1 was healthy. Another pass two orbits later confirmed it, then two more completed the return to the orbit where Roy had waited.

However, one test was insufficient data to retire the risk from lunar entry velocities which would need to burn off ten times the velocity Siegfried had started with. Transferring much of its stored propellant to fill Siegfried's depleted tanks, Roy tested its own engines with fully propulsive maneuvers, then set to work on a series of tests of the aerobraking technique under more and more aggressive initial conditions. First, Roy would boost to a planned initial apogee, then over an appropriate number of passes brake down to LEO again, simulating the tail end of a multi-pass return from translunar booster or lunar return trajectories. The apogees rose from 1,200 kilometers on Siegfried's first test to 2,500 kilometers on Roy's first, then to an altitude above 7,250 kilometers which would require sweeping through the entire inner Van Allen Belt, and finally to an apogee just above geostationary orbit.

What had been tense on the first trial quickly became routine, as each multi-pass return required a multitude of passes and the knowledge of purely atmospheric orbital adjustments expanded by multiple orders of magnitude. The LTV demonstration controllers settled into a routine as grueling as a manned mission, but with the duration of an unmanned probe: a series of passes starting a few times a day, then rising to every few hours forming an intensive period in the middle of every week, followed by a few days of propellant transfers while the data was digested and the go-ahead given for another set. For a mission which had started with concerns it might not reach orbit, the routine was appreciated. The worst headache came during the highest energy initial passes, when meteorological models estimated elevated upper atmospheric density. While relaying instructions to LTV-2 to raise the perigee to reach the right density altitude for braking, an invalid command sequence was uplinked by accident. Attempting to parse the commands in preparation for the burn lead Roy’s computers to interpret the result as a radiation failure of its computers resulting from the pass through the Van Allen belts. The spacecraft tripped into “safe mode.” LTV-2 automatically adjusted its orbit ensure its perigee even in the worst case wouldn't result in an overly aggressive path, then switched to low-level operations to await a resolution. With the brake opportunity missed, NASA engineers on the ground spent the time to perigee diagnosing the problem and reworking procedures for command uplink on time-critical maneuvers. With updated commands uploaded, Roy made the proper braking pass on the next orbit and every one after it until it returned to its rendezvous with LTV-1 in LEO.

Other than the one headache, Roy held up under the trials as well as Siegfried had, and data from both continued to confirm expected boil-off rates. With almost ten weeks of evaluations under their belts, McDonnell and NASA engineers carefully assessed the health of both vehicles. The remaining propellant had been carefully husbanded for a fool-proof flight of both tugs. For the first time, both tugs departed LEO together as a stacked unit. Roy's engines were called upon one more time to push both tugs to an apogee near that of GPS satellites. As Roy cast off and adjusted its perigee for a four-day return to LEO, Siegfried lit its own LTME cluster, burning nearly all its remaining propellant to push itself onto a circumlunar trajectory. Not only would LTV-1 make the most aggressive test yet of the system's aerobraking, but it would also become the first LTV to fly--however briefly--past the body they were intended to reopen to human access.

Engineers monitored the status of the vehicle on its outbound trajectory, as Roy settled with little notice into a long-term parking orbit to await pickup by Shuttle for inspection. Images from LTV-1's docking and navigation cameras captivated many audiences back on Earth as they captured the Earth shrinking behind it, then the growth of the moon from a disc to a ball and finally into a rugged, rubble-strewn surface spread out beneath. Siegfried shot past the limb of the moon, beyond the view of Earthbound observers and communications, past the point on a full flight where it would have fired its engines to enter lunar orbit, then flew once more into view. The spacecraft's communications reassured controllers: LTV-1 was on course and speed, headed for the first of the 60 passes which would distribute its braking energy. The originally planned 90-day LTV Demonstration mission drew comparisons to Apollo 9, playing a similar role to the mission which had come nearly thirty years before. It was, in some ways, even more ambitious: not just the LTV's first flight in space, but a full demonstration of nearly every capability of the entire system. Once LTV-1 and LTV-2 were returned to the ground, the final preparations could be made for the launch of the Lunar Transfer Vehicles still being finished: their near-twins, LTV-3 and LTV-4, already test-fired at Stennis and in final assembly at the Cape, and LTV-5 and 6 still under construction at McDonnell's plants. However, before they could return home aboard the Space Shuttle, the Space Lifter’s issues needed to be resolved. The stages waited, circling in a low Earth orbit, for their ride home.

The major details of the Engine #3 failure on STS-240 emerged quickly, almost as soon as the first responders were able to examine the engine and spot the gaping holes in the turbopump assembly. The failure had been the result of a catastrophic failure of the pump’s turbine assembly, which NASA knew was one of the oldest in the F-1B fleet. As NASA, STC, and Rocketdyne tore down the remains of Engine #3, the initial leading explanation was fatigue cracking of the turbopump impeller blades--a major concern with the long-term life of rotating hardware. As a precaution, the turbopump’s turbine and impellers were routinely inspected after every flight with a borescope. However, as the F-1 family had a history of nearly two thousand in-flight firings without issues, engines with no other warning signs were typically only removed and fully torn down during the ongoing SLIP inspections, which had quietly transitioned from a “Spacecraft Lifespan Investigation Program” to a“Spacecraft Lifespan Improvement Program”. Engine #3 had been inspected and reinstalled at Constitution’s SLIP IV inspection in 1993, and was due for replacement at SLIP V in 1996. As a prime area of concern in a SLIP inspection which NASA engineers might have been overdue, the chunks of turbine blades were carefully extracted from the aft end of Constitution’s engine bay and catalogued and the impeller’s violent disassembly carefully reconstructed. By comparing the length of each blade remaining on the hub, the engineers could reconstruct the order of the blades’ failure, finding which had failed first and which had failed as shards of other blades was blown into them by the pressure gradient.

As the engineers attempted to reconstruct the failure order, they made an interesting observation: the pattern showed multiple initial points of failure. Moreover, when sections of the blade were subjected to metallurgical testing and visual inspection, looking for signs of fatigue crack initiation near the failure point, none were found. The inspections turned towards the unusual pattern of damage to the blades, looking for other explanations. Fatigue of the impeller blades had apparently not been the root cause--instead, the blades had been broken by some other fault. Once this was understood, other evidence that had been accumulating was recontextualized, and the truth emerged: the damage to the seals between the fuel and oxygen impellers wasn’t a side effect of damage, but the cause. Unusual wear to the seals between the turbine shaft and the case had allowed a leak between the two impellers. Sensors registered the worsening mismatches in fuel and oxidizer flow, resulting in uneven gas generator power and main engine thrust. However, before the stage could take action, the mixture had ignited, damaging blades and rotor bearings, driving the shaft out of alignment and balance. This had caused otherwise healthy blades on the impeller to contact and clip the case wall. The result had been a catastrophic failure of the impellers and an explosion of shrapnel and shards as the engine’s sensors belatedly reacted to close off propellant flow.

Locating the cause of the failure had ultimately taken a mere 11 days, as technicians and engineers had worked side-by-side around the clock. Resolving it would take several times longer. Every available flight engine was scheduled for teardown and inspection of their turbopump assembly, and other seals throughout the engine were re-evaluated. Intrepid, which was in for her own SLIP IV inspection, already had had her full suite of engines removed and made the main subjects of the inspection. One seal turned up similar damage. Though not serious enough to cause a major leak, the confirmation of the cause caused mixed feelings. The confirmation of the source of the issue came as a much-desired relief, but the issue was also a wake-up call that suggested that other issues might lurk within the Space Lifter’s RS-IC fleet. The F-1B design was nearly twenty years old, based on a design closing in on forty. Much as had been revealed six years prior on the S-IVC assembly process, familiarity had bred complacency. Major inspections were scheduled for every RS-IC booster in the fleet over the next months. RS-IC-604 Liberty was the first to be certified as clean. As the youngest Lifter, her SLIP schedule had her most recently out of SLIP’s hands and with her most recent inspections she already had a set of freshly torn-down and rebuilt engines installed.

NASA investigators reviewed every available scrap of documentation regarding her inspections before finally certifying Liberty as fit to fly. When STS-240 had caused shades of Magellan’s failure to swim before NASA observers, there had been worries a similar year-long stand-down might result. Instead, Liberty and the STS-241 mission were rescheduled for March 4, 1996. The payload was a pair of Hughes communications satellites, paid for by a satellite television supplier aiming to build out their global market. The customer had willingly accepted the risk of the mission in exchange for being bumped to the head of STC’s launch queue and a highly secretive discount on launch price. The launch went off without a hitch, and inspection of the engines after the mission showed no issues. While this would delay the typical rapid RS-IC turnaround, the rest of the RS-IC fleet was finally being cleared of the turbopump issues. The Space Lifter began to ramp back up to operational status with the launch of the Space Shuttles Discovery and Destiny aboard STS-242 and 243 mere weeks apart, with STS-242 retrieving LTV-1 and STS-243 retrieving LTV-2 in twin missions. The return of the stages to Earth marked a dramatic end to a test mission which had seen, aboard its launch vehicle, a dramatic benefit of both the lifecycle risks associated with reuse and the safety benefits enabled by the return of hardware for inspection.

With the success of the mission and the transition of LTV from a test phase to a man-ready transport system, the vehicles were all to be given names. Originally, the Public Affairs office had selected the names Lewis and Clark to be bestowed upon LTV-1 and LTV-2 upon their recovery by the STS-242 and STS-244 missions, named for the famous American explorers. Unfortunately, the high profile of the LTV Orbital Demonstration in the wake of their barely-successful launch worked against them. Despite official injunction, Siegfried and Roy remained in common usage among the LTV support staff, a fact which delighted the public, and the magicians themselves, when Popular Science revealed this fact in a human interest article in 1996 titled “Lions and Tigers and Rockets, Oh My!" The NASA PAO eventually gave up on trying to institute the new names, quietly retroactively authorizing the original call-signs and assigning the original planned names to LTV-5 and -6 instead. LTV-5 and -6, in turn, passed their planned names on to the planned LTV-7 and -8, to enter service in the early 2000s. Those, eventually, would take the names Amundsen and Scott. The first four LTVs to be named were gathered for their christening, with the space-flown LTV-1 and LTV-2 presented on dollies next to their pristine pre-flight counterparts, which were with due ceremony named Tenzing and Hillary after the mountaineers who summited Everest. Once launched in July, these would await only the launch of an eCRV and crew to bring astronauts to lunar orbit for the first time since Apollo 17 had departed. In the meantime, the two spacecraft conducted their own more routine break-in period, testing their capabilities by carrying the first TDRSS-L satellites to lunar space.

The first flight of a Hermes capsule on the LTV would have to wait until 1997, when the Space Shuttle Destiny delivered an unmanned capsule to a docking with the LTV-3/4 stack, returned to LEO and refueled from their proving flights to deploy TDRS satellites to cislunar space. This mission, ILP-1, was doubly notable for the first demonstration of cryogenic propellant transfer from Trans-Pacific Launch Industries’ Sierra rocket, which transferred a small quantity of methane and oxygen from a tank in its payload bay into LTV-3 and back, cycling it back and forth several times to demonstrate TPLI’s ability to service the Lunar Transfer Vehicles, and to help prepare for TPLI’s coming propellant resupply missions. Coming on the heels of TPLI’s maiden launch of a full Sierra rocket from their initial test site at Vandenberg, these early propellant transfer missions were a critical part of TPLI’s process of proving out their new Sierra launch vehicle as they prepared for its entry into the commercial launch market. Indeed, the same mission which carried the test propellant transfer hardware for the ILP also carried another test payload: the first orbital demonstration of the new smallsat bus intended for use with Geostar’s Arachne LEO communications constellation. With confirmation of the bus’ functionality, Sierra began to work up their flight rate launching batch after batch of Geostar’s new constellation from Vandenberg while they completed final commissioning of their launch site at LC-40 in Florida.

TPLI’s successes in ramping up the Sierra flight rate over 1996 and 1997 would have been worrying enough for Boeing and the Space Transportation Corporation if their ambitions had been limited to low Earth orbits. However, Martin and Mitsubishi also had their eye on the same geostationary market which had, for years, been the nearly exclusive domain of the Space Lifter. For decades, the only payloads for which the Space Lifter had not been the first choice were those too small to economically use it or those customers with institutional concerns which prevented the use of an American launcher. The Russian Groza system had been some competition when it became to be available on the commercial market, but the cost savings over Lifter had been matched by concerns about Russian quality and export/import restrictions. In the wake of Groza’s muddled international debut, STC's expectation of a near-monopoly had only intensified in the early 1990s, culminating in their attempt to sabotage the memorandum of understanding between NASA and TPLI to eventually even consider certifying Sierra for ILP propellant.

Now, Sierra could not only match Lifter on cost for the mid-sized payloads which were STC’s bread and butter but reach even lower cost levels Lifter couldn’t hope to match. Worse, the Sierra debut mission had flown directly between the STS-240 failure and the Lifter’s return to flight--an issue caused by an aging rocket cast against the newest wave of reusable launchers. Though press releases were carefully polite, a small wave of geostationary service providers announced contracts with TPLI for “schedule assurance” backup slots aboard Sierra for payloads with scheduled Lifter missions in coming years. These might also draw on a new capability for Sierra-launched payloads to access this lucrative, higher-energy orbit: though initial GTO launches by Sierra were served with an Aerojet expendable solid third stage, news emerged in late 1996 of negotiations between TPLI, NASA, and McDonnell-Douglas to use portions of the LTV fleet in a single-stage commercial role delivering satellites to GTO or all the way to geostationary orbit between ILP missions. Now, Boeing was disquieted to not only face growing domestic competition but also to see their STC partner McDonnell-Douglas rapidly moving to take advantage of the situation. Though Lifter improvement, augmentation, or replacement plans had percolated within Boeing and Marshall Space Flight Center for years, the rapid emergence of Sierra as a real competitor meant that 1997 saw these plans rapidly gain support at the highest levels of Boeing’s space division.

While the competition between two of the launch vehicles which enabled it heated up, the unmanned Hermes flight to Low Lunar Orbit was a marvel of international co-operation: a European capsule launched by an American Space Lifter, with demonstration fueling from a joint American/Japanese launcher, and support from other nations around the globe. The mission carried a handful of scientific instruments and experiments (mostly radiation sensors to validate the capsule’s polyethylene shielding and a handful of student experiments focusing on either life sciences or lunar observation) in addition to its crash-test dummy passengers, and during its month-long quiescent stay in a near-polar lunar orbit, it demonstrated the use of high-efficiency electric thrusters like those intended for the Low Lunar Orbit Platform for station-keeping in the Moon’s extremely lumpy gravitational field (which, while mapped in greater detail by the Lucky 7 mission, remained a hazard to long-term missions near the Moon). However, its chief focus was the shakedown of the improved heat shield. Not since 1972 had human passengers reentered the Earth’s atmosphere at such a fantastic rate, and as much as computer models and hypersonic wind tunnel tests indicated that Hermes could withstand the challenge, no engineer or manager on the ground was willing to approve a crewed mission without a successful unmanned shakedown. The heady “waste anything but time” days of Apollo had given way to a more safety-conscious attitude, criticized by some as “overcautious,” “wasteful,” and even “effeminate.” These voices were few and far between, however--even the most enthusiastic advocates for the immediate conquest of space generally recognized that celebrations of heroic martyrdom would not sway congressional investigators if the worst did happen.

As it turned out, the unmanned Hermes capsule completed its month in Low Lunar Orbit without incident, and the LTV to which it was docked, LTV-4 “Hillary”, relit its engines successfully after a month of slowly orbiting the Moon. This marked the longest time yet between LTV engine burns, and testified to the efficacy of the spacecraft’s power and thermal control systems, as the month of rapidly-shifting temperature extremes had not seemed to impact its propellant supply. Several hours before Hillary came in for his (in a break from tradition, the LTVs had been addressed by male pronouns, a practice begun when First Lady Hillary Clinton toured Kennedy Space Center while LTV-4 was in the midst of pre-launch processing) first aerobraking pass, the capsule retracted its umbilical connection and oriented itself for a much hotter, deeper entry to Earth’s atmosphere. Drawing on Russian experience with the Zond program, Hermes used a “skip” reentry technique, to allow the capsule to maneuver in Earth’s atmosphere to its landing site at Edwards Air Force Base in California. This was the first of many technological innovations the ILP would demonstrate over the Apollo program, and eliminated the need for a large, costly fleet of naval vessels for regular recovery.

No sooner had the unmanned capsule been recovered in the Californian desert than NASA announced a launch date for the next mission in the ILP, ILP-2. Unlike ILP-1, ILP-2 would not fly a Hermes capsule at all, but deploy the Low Lunar Orbital Platform to the same polar orbit that the first Hermes had occupied. The LTVs assigned to ILP-2 would return without any payload. ILP-2 would also be propelled by LTV-3/4, after those vehicles were refueled by a series of Space Lifter and Groza flights. The final Lifter propellant flight also carried the LLOP, which, separating from the propellant tug, briefly maneuvered to its own docking with LTV-4. This operation was one of the more complex actions the LLOP would have to take during its lifetime--it was designed to primarily operate as a passive target for docking spacecraft, or to use its small robotic arm for payload transfer with docked lunar landers. While capable of maneuvering to a docking on its own, in the event of a lander failure at close range, its control systems were not optimized for that. Still, after one false start, the LLOP successfully docked with the fully-fueled LTV stack.

Departing Low Earth Orbit on September 9, 1997, ILP-2 entered Low Lunar Orbit four days later, and the LLOP separated from Hillary on-schedule. Extending its small set of solar arrays and radiators, the LLOP took its position at the same polar orbit that the ILP-1 Hermes had occupied months earlier. Like the earlier capsule, the LLOP was equipped with a set of electric thrusters for station-keeping. Though NASA public relations material played up the significance of this equipment, as it was the first use of electric propulsion on a manned spacecraft, its use was almost evolutionary, not revolutionary. Similarly-sized systems had been developed for stationkeeping at geostationary orbit for the larger busses a Space Lifter could dual-launch. Indeed, the LLOP’s system was the standard set of four thrusters with which Hughes had been equipping its geostationary satellites for years--which should come as no surprise, given that the LLOP was, ultimately, a Hughes commsat bus mated to a Grumman MPEM and equipped with a spare Spacelab robotic arm.

Though primarily intended for logistical support of manned and unmanned lunar surface operations, the LLOP did have one instrument for Earth observation. At the suggestion of Vice President Gore, inspired by the influential “Blue Marble” photograph taken by the crew of Apollo 17, LLOP was fitted with a telescopic camera that could photograph points of interest on the Moon’s surface, and also capture whole-planet views of the Earth. It was Gore’s hope that a steady stream of earthrise pictures, regularly uploaded to the NASA website for public consumption, might spur greater interest in environmental sciences. Though engineers at JSC and Hughes had griped about the late change to the spacecraft’s design requirements, the LLOP had enough power, communications bandwidth, and thermal control capacity to handle a camera and some smaller instruments. Like Spacelab before it, LLOP would serve as an anchor for opportune science experiments, even those with no connection to its original purpose.

All things considered, the Russian space program weathered the fall of the Berlin Wall far better than might be expected. Though budget cuts had been a fact of life after 1985, the military and civilian (though, in truth, the distinction is blurry) branches of the new Russian Federation’s program survived the period of 1989 to 1991 without catastrophic losses. The satellite constellations the Russian military had planned to support their overseas power projection were not growing, but Russia was in no condition to operate in Africa anymore anyway. The domestic satellites continued to provide communications and meteorological service even to the Russian arctic. No cosmonaut had been killed in space. Most importantly, Ukraine continued to supply Groza stages to its former master.

The situation began to change in 1994. The start of the Chechnyan War brought a sudden chill in Russo-Ukrainian relations, already tense due to disputes over Crimea and Sevastopol, and had suddenly thrown the availability of Groza stages into question. The Russian Federation was willing to invest money into securing the independence of its space assets from its western neighbor. The most immediate goal was the replacement of the Groza core stage with an indigenous Russian design. Energia rose quickly to the challenge, proposing a new, fully-reusable core stage powered by their state-of-the-art RD-701 rocket engine, an engine unique in that it could burn either hydrogen or a mix of kerosene and hydrogen. The proposed stage would be cross-fed from modified (stretched) Raskat boosters, off-loading a great deal of the core stage’s structural mass onto the boosters, which, staging at a lower velocity, had less impact on overall payload. The system was elegant, leveraged the best innovations in Russian aerospace engineering, and was far beyond the means available to the Russian Federation in 1994.

When Roskosmos told Energia as much in later 1994, the company took a while to get the memo. Yuri Semyonov, the company’s President, submitted designs for a Mir-2 that would be launched by the proposed rocket, and for 18-tonne communications satellites that it could deploy with a full complement of four Super Raskat boosters. Eventually, the Russian government’s patience wore out, and, with heavy government pressure, he was forced out. He was replaced with Oleg Sribielnikov, a former manager at NPO Salyut, which had manufactured the Proton rocket before that program’s cancellation.

Sribielnikov proved far more reasonable, and revised the core stage proposal into a staggered development scheme influenced by the American Space Transportation System, which did, sooner or later, reach its original goals. As Phase I, Energia would replace the Groza core stage with an RD-701-fired expendable rocket stage of the same diameter, which could be serviced with essentially the existing Groza support infrastructure in Russia and Kazakhstan. Phase II would involve the Russification of the Raskat system, building modified stages in Russia and modifying the Ukrainian-built stages to the new specifications. Phase III, ultimately, would replace the disposable core with a reusable one, along the lines of the original Energia proposal. The new vehicles would bear the names “Baikal,” for the booster, “Kama,” for the expendable core, and “Volga” for the reusable core. These good, Russian names would expunge the influence of the Banderites from the most visible symbol of Russia’s continued potency.

Unfortunately, it took longer to get the vehicles to the launch pad than the Russians initially hoped. While the RD-701 was essentially off-the-shelf in 1994 (having reached the test stand shortly after the dissolution of the USSR), corruption, budget-cuts, and poor quality-control, together with a brain drain of former Soviet engineers to the West and, to a lesser extent, saber-rattling minor powers, conspired to delay the first flight of the Kama booster until 1999. By then, however, a new administration had taken power in Russia. Led by charismatic authoritarian Vladimir Putin, and experiencing a new spike in revenue from gas sales to Europe and China, Russia endowed Energia with considerably more funding for the Baikal booster, which reached the launch pad in 2002.

To this point, the Russian engineers had been, to some extent, simply duplicating the work of the Yuzhnoye Design Bureau. The final phase of the Energia development scheme, the development of the Volga core stage, involved developing a winged vehicle that would reenter from orbital speeds. This was new ground for the Russian engineers, and worse, it was ground more important to the civil and human spaceflight programs than to the military space program. The Russian military had, with the launch of the Baikal-Kama system, regained its independent space access--the Volga core stage was, while interesting commercially, not worthy of funding from the Russian military. Despite a heavy investment from Gasprom and attempts at a partnership with China and with India, Volga appears far from the launch pad, and her future is uncertain.

The Mir space station was the most at-risk part of the former Soviet space program. As the most visible part of the Soviet space program, manned spaceflight was not going to disappear from Russia entirely, but flights to the station were cut back drastically. Plans to have the station permanently crewed were shelved in 1992, as the Russian manned space program became little more than a “show the flag” effort. The upgrade to the Uragan fleet's heat shields, replacing the original time-saving ablative coat with a tile-based system similar to the American Shuttles, seemed hopelessly optimistic in retrospect, as the long stand-downs between Uragan flights left more than enough time for complete TPS replacement.

This situation persisted, with Russia just proud enough to continue funding annual Uragan flights to Mir but not rich enough to do more, until late 1993, when American entrepreneurs Jeffrey Manber and Walter Anderson re-entered the picture. Through contacts Manber had gained in Russia in 1988, the two pitched a novel revenue stream for the Russian space program: orbital tourism. Under their proposal, an American company (named “MirCorp”) would purchase a 45% interest in the space station, with Energia (the Russian design bureau reorganized into a semi-private corporation) holding the remaining 55%. MirCorp would finance the modification of one of Mir’s laboratory modules (of which two remained in Energia’s warehouses, not fully outfitted) into a habitat module for visiting tourists, as well as partially subsidizing flights of tourists on Uragan flights to the station, similar to the way commercial comsats were loaded onto Shuttle missions with excess payload by STC in exchange for booster cost reductions. The company would also sell laboratory space in Mir’s other laboratory modules to customers in the US and Europe (and, later, India and China), taking advantage of low Russian flight costs and a wide-open flight manifest to market to scientists anxious to get their data before retirement. The arrangement would, for the first time, enable Russia to actually fly Uragan at something approaching the frequency of its American counterpart.

MirCorp found considerable support in the US State Department, which was eagerly looking for ways to slow Russia’s brain-drain. For a long time, the Soviet Union had cooperated with anti-American regimes, however questionable their actual Communist credentials, and with the demise of the Soviet economy, many of those regimes (like Iraq, Iran, and Libya) were inviting Russian rocket scientists to settle full-time and take positions as chiefs of their missile development programs. The US State Department was willing to assist any effort to keep Russian engineers in Russia, provided that it did not compromise America’s premier space power status. With NASA setting its sights beyond Low Earth Orbit and microgravity research, there was no obvious roadblock to cooperation between American and Russian companies in space. In partnership with the US Department of Commerce, the State Department established the Office of International Space Commerce, to regulate the import and export of orbital technology, in order to better regulate payloads as distinct from launch vehicles.

The first MirCorp flight, designated KU-1 (Kommercheskiy Uragan, or “Commercial Uragan”), launched in 1996, carrying a crew of two Russian cosmonauts and two MirCorp engineers, along with space tourist Dennis Tito (an investment manager who had bought a seat as one of the first MirCorp tourist customers). Their task was to prepare the space station for the delivery of the new MirCorp module, dubbed Kommertsiya, or “Commerce.” Over the course of their 14-day mission, the crew members installed power and cooling system cables to connect the new module to Mir’s core power and thermal control systems, and tested communications with MirCorp’s corporate headquarters (and primary technical support center) in New York City. Tito, meanwhile, used Mir’s Spektr module to test an optical communications experiment sponsored by the Space Studies Institute and Geostar, in which Tito was a shareholder. The experiment, which demonstrated high-speed communication by means of a laser to a spacecraft, involved signals from a station on Earth reaching a reconfigured sensor on Spektr, and demonstrated data transmission rates of over 100 megabits per second.

The second MirCorp flight, KU-2, launched in early 1997, carrying the Kommertsiya module, which was attached to Mir’s hitherto vacant starboard docking port. The crew, again two Russian cosmonauts and two MirCorp engineers, saw to the module’s installation and its startup, verifying that the microgravity exercise facilities, the new, American-designed “observation deck” (a very large window attached in place of an experiment bay), and the Visitor Airlock (a second airlock, complementing Mir’s core module airlock) were in working order.

KU-2 brought Mir up to a “fully operational” status, in the words of Roskosmos, and provided the additional revenue stream necessary for the station to be permanently manned. Shortly after that mission departed, the Russian government launched a new crew of four cosmonauts to the station, the first of a new class that would permanently occupy Mir. Their Uragan carried in its payload bay the Mir Escape Capsule, a stretched derivative of the Almaz capsule that had begun development in the late 1980s to provide emergency escape from the space station, allowing crews to occupy it between Uragan flights. The capsule, with six seats, was spacious enough to accommodate the planned full-time Russian crew of four, together with up to two MirCorp occupants. Settling in for a nine-month tour on Mir, Russia’s newest class of cosmonauts picked up the torch dropped by their Soviet forerunners.
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I thought this week's chapter started off a little abruptly, like where does this engine failure come from, but I think it speaks to the clear and incremental writing style that it didn't confuse too much. I think that means you did a good job! Also this is a wonderful accident, why don't you accidentally post the whole thing eh ;)

Edit: now that I have actually read the update, it turns out to be a great one, though unfortunately the tension built up at the end is now lost. The lunar lander is finally on a development track, and I'm eager to see how it is refined and ultimately used. Also, now that the full program of an ILP landing is laid out, it would be nice to have a diagram for all the missions needed for a succesful mission, akin to the one for the program in Eyes Turned Skywards: https://www.alternatehistory.com/wiki/lib/exe/fetch.php?cache=&media=timelines:artemis_conops.png
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Chapter 19: Gear Down
“MAKSimized Performance, with the MAKSimized record. MAKSimize your Career with Boeing.”--Boeing/STC Promotional Pamphlet, handed out at university career fairs between 1997 and 1998.​

Chapter 19: Gear-Down

With her engines throttling back for landing, Constitution shed speed quickly in the last minutes of her flight. As she fell, her onboard systems made the final preparations for touchdown.

The winged rocket may have been as large as a Boeing 747, but her aerodynamic qualities much more closely resembled the Concorde, or the XB-70 Valkyrie--like the other two supersonic planes, she cut through the atmosphere with a huge, swept delta wing. Unfortunately, while a delta wing worked superbly in the supersonic and hypersonic flight regimes, it could lift the Lifter only with difficulty as she bore down on the runway, crawling along at barely 200 miles per hour. Like all delta-winged planes, she had to point her nose to the sky, thirty degrees over the horizon, to achieve a high enough angle-of-attack for her wings to function.

Constitution’s nose in the air, her precariously perched pilots found their view of the runway blocked by the Lifter’s bulbous nose, leaving them landing virtually on instruments alone. This was no difficulty at all for trained naval aviators like Young and Crippen, who had cut their teeth on nighttime carrier landings, but that didn’t stop the engineers at Boeing from building into every Lifter a prosthetic eye, a tiny television camera mounted in a well under the nose along the spacecraft’s centerline, relaying a view of the runway up to a small CRT display on the dashboard between the two crewmen. As did the other instruments, that screen augmented the astronauts’ senses, giving them information that the classical five could not have discerned, integrating them ever so slightly deeper into the great machine whose brain they were.

When the Lifter reached an altitude of 500 feet, Young threw a switch to deploy the landing gear. With another loud whine, hydraulic motors driven by power bled off from the Lifter’s eight jet engines pushed the gear well doors open and extended the almost comically-frail legs beneath the Lifter’s immense bulk. Compared to the gear on a heavy transport plane or an airliner, these landing gear were thin and weak. Had the Lifter attempted to stand on them when fully loaded with RP-1 and liquid oxygen, they would have snapped like toothpicks. Only now, when most of the Lifter’s volume was mere vapor and air, could they support her weight.

Frail though they might have been, they had to bear the force of the Lifter’s impact with the Spacecraft Landing Facility runway soon, very soon. The pilots could not risk losing the spacecraft because they weren’t securely in place. Even as their dashboards lit up the indicators for “Gear Locked,” they called the Kennedy Space Center tower to confirm.

“Tower, this is
Constitution, can we get external confirmation that gear is down and locked?”

Constitution, your gear looks good from here. You are clear to land. Welcome back.”

The consolidation of the American aerospace sector reflected the changing face of orbital transportation in the US. As Sierra reached first its ground tests and then its flight tests, and as McDonnell-Douglas and NASA put the Lunar Transfer Vehicle through its paces in flights first between LEO and other points in cislunar space, the last major players in American space launch--Boeing and STC, half of which Boeing owned--took stock of their options for the future. The early attempt by STC to lock TPLI out of the launch market for SEI propellant launches had, somewhat predictably, backfired, and NASA committed to developing a launcher-agnostic propellant transfer mechanism that would enable the agency to launch propellant for its Lunar Transfer Vehicles on any reasonably large launch vehicle. This was the first chink in Lifter’s armor, though many more would become apparent later in the 1990s. The Russian Raskat-Groza system did, by some margin, beat the American launch system on cost, and a handful of new commercial satellites signed on with the ex-Soviet launcher. On the horizon, Europe’s interest in air-breathing propulsion was also a potential competitor, but not one STC took seriously.

TPLI was another story. Unlike Russia, Japan had the capital to invest in a new launch vehicle, and unlike the Europeans, TPLI’s backers had chosen a technically very conservative design--conventional chemical engines and two stages. Between that and Martin-Marietta’s ample experience with vertical landing, TPLI was well on its way to fielding an operational launcher in 1993, when the new satellite telephone company Iridium announced that it had contracted a dozen flights with TPLI to deploy its 72-satellite constellation to polar orbits. The company’s Sierra launch vehicle, while much smaller than the Space Lifter, was fully reusable, allowing TPLI to offer considerably lower per-kilogram costs to Low Earth Orbit than STC could offer on the Space Lifter without an outright government subsidy.

The combined threats of foreign launchers and the half-foreign Sierra led STC and its parent companies to explore successors to the Space Lifters, which, after 15 years of service, were beginning to grow long in the tooth anyway. Increasing pressure to make a decision came from the spate of Sierra bookings of Lifter payloads following the 1996 STS-240 turbopump failure. Like their European rivals, the American consortium at first flailed about without a clear direction as to what exactly could replace Lifter. They explored options as varied as air-breathing SSTOs, second-production-run Lifters carrying atomic, winged upper stages, conventional chemical TSTO designs, and even more obscure concepts like laser propulsion.

What finally precipitated a decision on the future of the Space Transportation Corporation, however, was a chance discovery outside Moscow by representatives of the Rocketdyne corporation, who were in Russia to evaluate claims about advanced staged-propulsion technology. Many of them had worked on HG-3, which had been planned to become the Space Shuttle Main Engine decades earlier, and so were America’s experts on staged combustion. While they did indeed find what they were looking for, in the form of N-1 heritage NK-33 engines, the more interesting discovery was a set of test-stand-qualified tripropellant rocket engines developed by the Glushko Design Bureau in the 1980s. These engines, designated RD-701 and RD-704 (two-chamber and single-chamber, respectively), could burn a mix of hydrogen and kerosene and used the highly efficient staged-combustion cycle that the Soviets had perfected for the RD-170. Rocketdyne’s managers struck while the iron was hot: as Energomash was looking for any source of income, they secured an exclusive contract to manufacture copies of the engines in the US, and brought the prototypes back to the US for qualification testing.

Word of the remarkable new engines spread quickly upon their arrival in the US. It did not take long for Boeing’s engineers to conclude that they answered a great many of the company’s dilemmas, and to incorporate them into a plan for a successor to Lifter. Boeing’s new plan called for a Lifter-derived first stage, stretched somewhat and incorporating more advanced thermal protection systems to survive much higher-velocity reentry than the first Lifter could handle, powered by 12 RD-701 engines (license-built by Rocketdyne under the designation RS-40 to satisfy the USAF’s skepticism toward about whether Russia could or would supply enough engines). Carrying kerosene and liquid hydrogen, the proposed Lifter II could loft a considerably larger upper stage and stage at a much higher velocity than the original Lifter. Boeing also proposed a new upper stage, powered by a modified hydrogen-only RD-701, which would bridge the gap in size between the Space Shuttle Orbiter and the Lifter. Incorporating internal hydrogen and oxygen tankage, it would match the role of the “Fuji” orbital stage from TPLI’s Sierra and finally realizing the dream of a reusable, winged second stage. Crucially, both stages would mostly fly unmanned, eliminating the risk of a loss-of-crew on routine cargo delivery flights (though a crew pod was one of the possible payloads for the new second stage). The near-miss during the launch of the Lunar Transfer Vehicles on STS-240 and the brief debate about whether an abort-to-orbit or an immediate return-to-launch-site should be attempted underscored the importance of that particular innovation, as both Energia and TPLI made a point of saying that, if it came down to their launch vehicle or their payload, they’d sacrifice the LV every time.

STC announced this Lifter II design (referred to in many early STC promotional materials as “MAKSimized Lifter,” in reference to the program for which RD-701 had originally been designed) in a major press event in early 1997, but the changes precipitated a reorganization of the relationship between Boeing, McDonnell-Douglas, Rocketdyne, and STC. The wave of consolidations in the 1990s and the new Space Exploration Initiative had given new strength and focuses to each of the firms. McDonnell had gained a new focus on on-orbit operations through the LTV, and was strengthening its investment in satellite manufacturing and operation. Boeing, in turn, had through its acquisition of most of Rockwell International become the leader of American manned spacecraft construction and operation, and it planned to tackle both stages of the Lifter II alone. Rocketdyne shareholders used the company’s rights to the RD-701 as a bargaining chip, and secured a large profit when the company was finally bought out by Boeing. With essentially the entire vehicle constructed in-house on new blueprints by Boeing, the new system had almost no Saturn or Apollo heritage. Instead of bearing the RS-IC or S-IVD designations, the new vehicles would simply be called Lifter II and Shuttle II (to be eventually condensed down to just Lifter and Shuttle when they supplanted the older vehicles).

The partnership between McDonnell-Douglas and Boeing began, then, to break down. WIth McDonnell primarily operating the LTV (which would provide, eventually, the majority of flights for American payloads to geostationary orbit) and no longer having a stake in the flight from the ground to LEO, the company planned to contract with TPLI to provide propellant for the LTV and even to recover it for servicing. As this situation developed, Boeing proposed the radical step of dissolving their old partnership and simply buying out McDonnell’s share in STC, which would become a wholly-owned subsidiary of Boeing. With the Commerce Department’s blessing, the deal went through in 1997, and the Space Transportation Corporation became a Boeing trademark that year. McDonnell-Douglas, however, continued to provide S-IVD stages for Space Lifter operations until the final retirement of that system in 2002.

The development of the MAKSimized Lifter proved a surprisingly straightforward program. With the engines essentially completed, the primary challenges were fabricating an entirely new airframe and testing the autonomous RTLS software. For a company as experienced as Boeing, these were straightforward challenges, and the Lifter II swiftly met its development milestones, reaching powered atmospheric flight tests by late 1998. Early in 1999, the first Lifter II arrived at Stennis Space Center for a static fire test. Emplaced on the same stands that had once tested the first Lifters and their Apollo-era progenitors, its twelve RD-701 engines roared to life together for the first time, finally demonstrating on American soil the full potential of the staged-combustion cycle.

The Lifter IIs would spend much of 1999 and early 2000 in atmospheric tests alone, unfortunately. The reusable second stage proved a tougher issue, as it faced the far rougher challenge of reentering from orbital velocity. Weight overruns frequently threatened to doom the program, and Boeing’s engineers had to work relentlessly to shave off excess weight while, at the same time, not compromising the new vessel’s structural integrity. Subscale test articles, launched on sounding rockets and, once, as a Shuttle secondary payload, helped to validate the aerodynamic design and the performance of the lightweight (but somewhat fragile) metallic heatshield, which promised lower maintenance costs than those which had dogged the original Shuttle.

The biggest hurdles that the Lifter replacement effort had to clear were not technical, but administrative. The Lifter was, for a long time, the only launch vehicle that could loft the US government’s heaviest payloads, military and civil. By the late 1990s, the system had demonstrated an unmatched flight record, with well over 200 successful orbital insertions and only one loss-of-payload event. The National Reconnaissance Office had come to depend on the Lifter, as no other American launcher could orbit KH-12 satellites or service them (as the Lifter could when it launched the Shuttle). NASA depended on it for crew access to space (though an effort to develop a Commercial Crew Services contract foundered after opposition from Texan congressmen). The contracts between STC and the US government, going back to that venture’s foundation, had insisted on the company keeping Lifter services available to the government even in the absence of commercial customers. While the Lifter dominated the commercial launch market, this was never a problem.

By the late 1990s, the changing economic picture in space meant that Lifter’s flight rate would fall by 50%, mostly US government flights. The Lifters were also growing long in the tooth after between fifteen and twenty years of operation. Constitution’s engine loss was only the most dramatic example of a growing list of maladies reported at every SLIP inspection, from failing hydraulics to unreliable electronic to fatigued structural members. STC began to suggest that Lifters would have to be overhauled more often to maintain reliability, at greater expense. While the company could, technically, have operated Lifter and Lifter II in parallel, it would have had to rely on a fairly large US government subsidy to do so.

It was these considerations that led STC and then Boeing to pursue a revision to their launch contract with the US government. The biggest sticking point, raised by the Astronaut Office in Houston, was the lack of an abort system on the crew pod to be carried within the Shuttle II payload bay. There was simply no identifiable survivable abort mode in the event of a second-stage breakup; even if the crew pod had the ability to independently reenter the atmosphere, it would have to break its way out of the Shuttle II payload bay first, requiring a complex system of explosives that would, most likely, damage the capsule itself on the way out. Boeing preferred instead to give its fully-reusable system a much more extensive flight-test program than any rocket but Sierra had received before, a flight test program much closer to that which their airliners underwent than any previous manned spacecraft. Though the astronaut office remained conservative, it eventually signed off when Boeing proved that the probability of a loss-of-crew would be the same or lower on Shuttle II as it had been on the original vehicle. With that issue settled, the Launch Contracting Office signed a revised contract with Boeing, allowing for the gradual phase-out of Lifter services from 2000 to 2002, and the reopening of manned flight service with Lifter II in 2001.

The USAF took longer to persuade, and for time the service considered a new Complementary Reusable Launch Vehicle contract, allowing it to retain a Lifter and a set of S-IVD stages in storage in the event of a Lifter II stand-down. The biggest concern for that service was its fleet of KH-12 satellites and the manned craft that serviced them. Every few years, a replacement satellite did have to go up, even if the all-digital KH-12 had a nearly-indefinite orbital lifetime. Ultimately, they decided against that--as Boeing’s lobbyists argued, the Lifter would not be retired until Lifter II had completed a flight-test program that would certify it for airplane-like reliability. Once that happened, the risk of a Lifter II fleetwide stand-down became very small--even if a single vehicle failed, the rest of the fleet would not necessarily have to stand down. After all, even catastrophic aerial disasters did not ground the entire Boeing 747 fleet. Finally, even if the worst should happen and the entire Lifter II fleet had to stand down, the actual risk of losing satellite coverage was small. There were enough KH-12s in Low Earth Orbit to survive even the loss of a single satellite, and they could survive a delay in maintenance. The risk, Boeing argued, was manageable.

For a while, the USAF still wanted to hedge its bets. The Gulf War and the later US interventions in Yugoslavia and elsewhere demonstrated the importance of real-time satellite reconnaissance in the modern battlefield, and the Joint Chiefs of Staff did not want to lose that critical advantage. However, as the National Reconnaissance Office’s budget shrank in the absence of the Soviet threat, the desire to not waste funds maintaining a mothballed Lifter I backup fleet overcame their caution, and the USAF agreed to shift to Lifter II launch services beginning in 2002.

While Russia’s space companies worked to leverage their experience in space vehicles and human spaceflight to survive in the 1990s, Ukraine inherited the Soviet Union’s launch vehicle industry, and had to find a way to make that pay dividends in a world where the US, Japan, and Europe were all working to lower launch costs. While the Raskat-Groza system was partially expendable, low labor costs in Ukraine and at Baikonur helped keep the system’s launch costs noticeably lower than those of the American Space Lifter. That Russia’s military and civil space programs, even downsized, demanded dozens of flights per year helped even more by providing an economy-of-scale that reduced manufacturing costs for Groza even further. Unfortunately, the ‘brain drain’ problem that afflicted the entire former Warsaw Pact did not spare Ukraine--as the 1990s dragged on, young and talented Ukrainians tended to leave home in greater numbers, emigrating to Russia or Poland or the West, as the Ukrainian economy could not provide them with the standards of living to which they aspired, nor properly fuel their professional ambitions. Quality-control, never as exacting in the USSR as it was in the West, suffered noticeably after the demise of the Soviet Union, and a number of payloads were lost in the 1990s.

Complicating matters was the fact that the Raskat-Groza upper stages were manufactured in Russia, not Ukraine, and the launch pads for the rockets were in Russia or in Kazakhstan, the latter of which negotiated a leasing agreement for individual pads at Baikonur Cosmodrome, allocating Sites 41 and 45 to Ukraine and 250 and 110/37 to Russia on a 20-year lease agreement. Launch services, then, had to be negotiated with at least two, and more often three, governments, a bureaucratic headache that made Western satellite builders reluctant to jump ship from Lifter to Ukraine (particularly with TPLI on the horizon, promising still-lower costs without the diplomatic complexities). More nationalistic Ukrainian politicians often condemned this dependence on Russia, but could not find a good solution for the problem--no launch pad in Ukraine could avoid sending payloads over Russia or another country, even if one were available, and money was scarce. A somewhat quixotic Polish proposal, wherein Raskat-Groza would be mated to a new Polish-built upper stage and launched off a converted oil platform (to be manufactured in Gdansk and towed to the mid-Atlantic) briefly gained traction but foundered on the lack of investor interest in Poland, and the fact that Poland had never built a rocket of such size (while Polish engineers at PZL Mielec insisted they could do as the Russian Kuznetsov Design Bureau had done and shift from turbojets to rockets easily, Ukraine’s engineers, remembering the difficulty with which NK-33 had come into existence, were more skeptical). Even so, the sheer number of rockets launched by Russia kept the Ukrainian launch industry afloat, giving the Ukrainians more time to seek foreign customers.

The beginning of MirCorp operations was a boon to Ukraine’s launch vehicle industry, increasing the demand for Groza core stages and spare parts for the Raskat boosters (needed in greater numbers to launch the heavy Uragan orbiters) and providing a healthy infusion of capital to the Yuzhmash company. The added capital allowed Yuzhmash to invest in a heavier degree of automation of the Groza manufacturing process, reducing manufacturing cost while also improving quality control by eliminating dependence on skilled craftsmen who were, by the mid-1990s, retiring without replacement.

Ukraine’s success in manufacturing and operating a reusable launch vehicle did not go unnoticed outside the country. As the European Space Agency ran into delays and budget overruns in the development of Alan Bond’s hypersonic air-breathing engine, a desire emerged for an interim booster for Europe’s LR program. Raskat, combining high-performance engines with a long history of successful recovery and refurbishment, was an early favorite, even though it was not manufactured in an ESA member state. The booster promised low development costs (as its use on the LR would require some modest structural changes for attachment to the hydrogen-burning LR core stage) and suggested a way to entice Ukraine to seek closer ties to the European Union and NATO, in the manner of the Visegrad Group. Though Ukraine’s government had been reluctant to antagonize Russia, the outbreak of the Chechnyan War in 1994 led to a reevaluation of Ukrainian foreign policy in Kiev. Combined with a sudden wave of corruption scandals, the Ukrainian government of Leonid Kravchuk was voted out and replaced with a new, Western-oriented government under former Yuzhnoye Design Bureau engineer Leonid Kuchma that emphasized a combination of the Shock Therapy reforms that were beginning to bear fruit in neighboring Poland and a focus on high-technology capital investment, which, according to their rhetoric, had propelled Japan and the other Asian Tigers to great heights. In this context, the proposal from Arianespace to Yuzhmash to modify Raskat as an interim booster for the LR found support among powerful officials in France, Germany, and Ukraine.

With the LLOP deployed to its target orbit and happily sending back new Earthrise pictures every two hours, and LTV-4 on its way back to Earth, NASA gave the go-ahead to prepare for the first manned mission beyond Low Earth Orbit since 1972: ILP-3. Launching on February 24, 1998, the crew of ILP-3 would transfer from the Space Shuttle Discovery to their Hermes, carried in the Shuttle’s payload bay. Their craft’s callsign remained secret until they reached Low Earth Orbit, but when they did, and when the Shuttle arrived at the LTV-5/6 stack that would hurl them to lunar orbit, the first manned Hermes spacecraft, Challenger, presented itself to the world with a successful undocking from the Shuttle’s payload bay and an unsurprisingly flawless rendezvous-and-docking with LTV-6.

For the first time since Apollo 17, a human crew rode a rocket’s column of fire through the Earth’s energetic radiation belts and out of the protective embrace of its magnetic field. Lighting up the evening sky over the Pacific with the familiar headlights-in-fog glow of a rocket in Low Earth Orbit, the four crewmembers, three Americans and one Russian, began their long journey back to the Moon.

ILP-3 was a minor media sensation. Every day on the outbound flight, the entire crew gave a televised interview carried by the major American TV networks, while the Russian cosmonaut Sergei Avdeyev gave longer personal interviews on RIA Novosti, reflecting on his role as the first Russian to travel beyond Low Earth Orbit and emphasizing the enabling role of Russian biomedical research on Mir and the Salyuts and of Russian propellant launchers to the success of the International Lunar Program. However, it was, in many respects, a by-the-numbers mission. The Hermes, after all, had already had its shakedown on ILP-1, and the LTVs, by now, had a half-dozen missions under their collective belt. LLOP had verified its own power, thermal control, and communications systems a dozen times over since its own launch. The only real tasks for ILP-3’s crew were to verify the Hermes life-support system on a two-week cruise, to verify LLOP’s life-support systems for the few days they would spend in lunar orbit, and to test certain communication equipment that the Jet Propulsion Laboratory was developing for use on teleoperated lunar rovers that would take advantage of the low signal latency between LLOP and the Moon’s surface as it passed overhead. In other words, their job was to not die, and to not break the radio equipment before it had been tested. They in fact filled a great deal of their outbound flight with educational demonstrations videotaped for NASA’s education office to send out to schools across the United States. Still, crew morale was high during the outbound flight, and the (literally) otherworldly experience of gazing at the Moon from only one hundred kilometers away dispelled the tensions that had begun to build on the cramped voyage uphill.

The teleoperation equipment passed its diagnostics tests with flying colors, to the relief of engineers at the Jet Propulsion Laboratory who were, in 1998, hard at work on the first American unmanned rover. Since the Apollo and Viking programs of the 1970s, JPL had lobbied for a mission to send large (several-hundred-kilogram) nuclear-powered rovers to the Moon and Mars, to follow up on the discoveries made by the J-Class Apollo missions and the stationary Viking landers. The Soviet Union’s Lunokhod program had proven the concept, as had the manned Lunar Roving Vehicle packed on the last three Apollo missions, but with NASA’s attention focused firmly on the Space Transportation System and enthusiasm for Mars surface exploration at its nadir following the inconclusive results of Viking’s biological experiments, the idea had never caught on. The Space Exploration Initiative had breathed new life into JPL’s efforts, as the new focus on the Moon and Mars--the only near-term destinations for human explorers--brought with it a new interest in funding for robotic missions to blaze the trail. Following the successful orbital insertion of the Mars Observer spacecraft in 1993, Congress approved for NASA’s FY1994 budget the Planetary Rover Program, as a complement to the Observers.

In accordance with Dan Goldin’s “Faster, Better, Cheaper” slogan, the Planetary Rovers would rely on a common bus developed for both the Moon and Mars, to encourage some degree of mass-production and to minimize development time between funded missions. The Rovers would all have a mass, depending on payload, of between 500 and 550 kilograms, which would allow them to land on Mars using Viking-heritage landing systems or on the Moon using a lander fueled by a single LTV stack. As JPL’s engineers worked longer on the Planetary Rover design, they settled on a configuration that they believed would suffice for any near-term planetary environment: each rover would consist of a single chassis, equipped with a rocker-bogie suspension system, a platform on the rear bed on which different power supply systems (RTGs or solar arrays) could be mounted, a robotic arm, and a camera mast, both of which could mount a variety of scientific instruments.

In an interesting deviation from traditional American spacecraft, the specified power source for the Lunar and Planetary Rover series was neither photovoltaic panels nor plutonium RTGs, but new RTGs designed to use strontium-90. The cessation of American plutonium-238 production in 1988 made the latter material a valuable commodity, one that NASA preferred to hoard for missions to the outer planets, where plutonium-238’s very long half-life was crucial to maintaining a spacecraft for the many years it would take simply to cross the vast interplanetary gulf. While strontium-90 had a lower power-density and half-life than plutonium-238, it was far cheaper than the heavier isotope, as it was produced as a waste product in commercial nuclear reactors, from which it was already commercially harvested for use in radiotherapy. The Department of Energy’s acquisition of a license to copy a Soviet strontium-90 RTG design streamlined the change-over at NASA, freeing at least some of the agency’s planetary exploration dreams from the logistical constraints plutonium imposed.

The first such rover was planned for deployment with the first LSAV, scheduled for early 1999. Though Martin-Marietta had brought their considerable experience to the table, the lander’s broad outline still closely resembled the design that NASA outlined in 1995: a ring of spherical propellant tanks, wrapped up in foil insulation, encircling a pair of Lunar Transfer Main Engines. Atop the propellant tanks was an aluminum mesh platform with a folding ramp, to which payloads could be bolted. Four spring-loaded legs marked out the corners. The entire spacecraft was just over 6 meters in diameter, which meant it could not be retrieved in the Space Shuttle payload bay, though it could be fit into the Sierra payload bay. For the moment, NASA had no plans to return a LSAV to Earth; all servicing on that vehicle would be performed at the LLOP.

The original NASA plan for testing the LSAV had called for an Earth-orbit demo flight prior to the actual first mission to the Moon. However, the LSAV’s ground testing program (particularly tethered landing tests at the Space Power Facility near Sandusky, Ohio) had been so straightforward that the decision was made to condense the first two missions into one and excise the planned quiescent period in Low Earth Orbit between missions. As a result, the ILP-4 mission would see not only the first flight of the new LSAV, but its voyage directly to the Moon’s surface and then back to Low Lunar Orbit.

Launched on February 2, 1999, the first LSAV, named “Albatross” after the migratory bird renowned for its endurance and the distances it travelled, and as an homage to the Lunar Modules Eagle and Falcon, was launched with its lunar rover payload by the Space Lifter Independence. Albatross was put through her paces in Low Earth Orbit, deploying and retracting her landing gear, maneuvering in formation with her S-IVD, transferring propellant back and forth to a small extra tank mounted to the forward end of that stage, and, finally, burning her main engines just long enough to prove that the design already validated on the LTV was still functional. With that done, Albatross departed her booster and chased down her waiting LTV stack (LTV-1/2, Siegfried and Roy), which carried her on the next leg of America’s return to the lunar surface.

After a (by now) routine transfer to Low Lunar Orbit, Albatross separated from Roy and took her first independent flight around the Moon. Her first destination was the LLOP, where she autonomously approached the small space station until the platform’s robotic arm latched onto her flank, bringing her into an unpressurized berthing port on the LLOP’s nadir side. The arm then performed an all-around inspection with high-definition cameras, beaming back signals to Earth. Though TPLI had built a support framework so that it could fit into Sierra’s payload bay, the cost of shipping the LSAV back to the Moon from Earth was high enough that NASA had no desire to ship it down as often as the LTV’s had been during their testing program. Its main moving parts--the LTMEs--had racked up many hours of flight time and hundreds of hours on the test stand before Albatross ever took flight, and the LTVs had proven remarkably resistant to damage from radiation, micrometeorites, and the variable thermal environment in space. Though the LSAV was taking the next small step, both NASA and its contractors were confident enough in its durability that its first few inspections would be done at the LLOP, in orbit around the Moon.

Fortunately, neither the spacecraft’s diagnostics instruments nor LLOP’s visual inspection revealed any obvious flaw with Albatross, and when the spacecrafts’ orbit around the Moon precessed far enough, NASA and JPL gave the authorization to undock from the LLOP and begin America’s first descent to the Moon in over twenty-five years.

Like the Apollo planners before them, the planners at JPL for the first Lunar Rover mission had to balance accessibility with scientific value when choosing their landing site. They had the added complication of having to choose a site of secondary interest, so as not to waste resources by going to a site slated for a manned visit. In effect, they had to choose a site that was interesting, but not at the top of most geologists’ wish lists.

Luckily, they had new information at their disposal for which their forerunners might have killed. The Lunar Observer satellite, which had entered lunar orbit in 1994, had revealed new and surprising information about the Moon’s chemical composition, indicating that a strange mix of elements called “KREEP” (for Potassium, Rare Earth Elements, and Phosphorus) was mostly present in two regions on the lunar near side--in Oceanus Procellarum, the Ocean of Storms, and Mare Imbrium, the Sea of Rains, the (relatively) new impact crater on top of it. Geologists were eager to study these terrains up-close, to get at a reason for that concentration, and to perhaps find the reason for the great dichotomy between the Moon’s far and near sides. Why, after all, must almost all the lunar seas be on the Near Side?

Many of the sites with high KREEP concentrations, like the craters Aristarchus and Copernicus, were already slated for manned missions, but there was no shortage of regions of interest for the first Lunar Rover. Ultimately, JPL settled on the Montes Jura, the rugged mountain range around the Bay of Rainbows (Sinus Iridum) at the north-west corner of Mare Imbrium, a region that the Lunar Observer’s spectrometers had indicated was high in thorium and other rare-earth elements, suggesting an abundance of KREEP.

It was toward the Montes Jura, the furthest point from the Moon’s equator that any spacecraft, manned or unmanned, had ever visited, that Albatross descended, carrying her still-dormant cargo. Approaching from the north, over the rugged terrain around the Moon’s north pole, she had de-orbited herself and fell most of the way down toward the Moon, in a sweeping elliptical orbit that just happened to pass within the Moon’s surface. As she approached her final destination, the lander relit her engines, cancelling almost all of her velocity, narrowing that ellipse ever further until it was almost a straight line between herself and the Moon’s core. As engineers at JSC, JPL, and Martin-Marietta held their breath, she beamed back crystal-clear video of her descent, the colors of the Moon resolving from their light-and-dark-grey appearance to a collection of tans and browns and greys, terrain sculpted only by volcanism and meteorite impacts once again receiving visitors from the world of wind and water.

Soon after the Bay of Rainbows, the broad, flat plain south of Albatross’ landing site, slipped below the Moon’s near horizon, the lander was in its terminal descent. Her two engines had throttled back as far as they could, blasting only a thin wisp of smoke and steam down to the Moon, as her radar altimeter counted off the last few meters until she touched down.

When she at last lit upon the Moon’s dusty surface, it was almost an anticlimax--her terminal descent had been so gentle that the only indication of landing was a contact light going off on her support team’s consoles, over a second after the fact. It took a moment for the reality to sink in, that for the first time since Apollo 17 the US had soft-landed a payload on the Moon. Mission Control in Houston exploded in a celebration that lasted a good hour, though not everyone could join in--some engineers had to remain at their desks, watching Albatross’s telemetry and that of the Lunar Rover, ensuring that nothing critical had broken on the way down, that the payload was in shape to roll out.

After a 6-hour checkout period, Control gave the order for Albatross to unfold her ramp, and for the Lunar Rover to unfold its six robotic wheels. In total silence, an aluminum mesh descended to the Moon’s surface, forming a 45-degree ramp (insanely steep by Earth’s standards, but safe enough in the Moon’s weak gravity) down the three meters that separated the Rover from her destination. Then the Rover came to life, unfolding her six wheels, extending her radio and television masts, pointing her high-gain antenna at Earth (and communicating with the LLOP through her short-range omnidirectional antenna), and giving each of her moving parts a diagnostic spin before she could actually begin her mission.

When JPL was satisfied that she had made it from the Earth to the Moon intact, they sent her commands to roll down the ramp. In almost real-time, they watched as the Moon came up to meet the rover, until the television camera gave a light jolt when the wheels met the dust and the rover’s suspension absorbed the impact. Once her six wheels were all on the Moon, the real work began.

Over the course of her mission to the Montes Jura, Lunar Rover 1 would set new records in planetary rover endurance and range. During her first lunar day, she only drove one kilometer, but as her operators gained confidence in themselves and in the new machine, they pushed her farther. On her fourth lunar day, she drove almost 17 kilometers, breaking Lunokhod 2’s record of 16.5 kilometers in a single day. Her travels took her from the level of Sinus Iridum to the heights of Point Laplace on its eastern “shore,” and her geological instruments greatly improved scientists’ understanding of the distribution of rare minerals on the Moon’s near side. Daily updates on her progress became the single most popular feature on NASA’s website, despite the agonizingly slow download times necessary to download the immense, multi-megabyte photographs, and her lunar sojourns would become the basis for a very successful IMAX film, shown in aerospace museums across the United States even a decade after her landing.

Most relevant to later lunar missions, though, was an experiment carried out by the ILP-5 crew during the Rover’s third “day” on the surface (two months after landing). During the 10 minutes they were within line-of-sight of the Rover, they communicated with it and controlled it directly from the LLOP, demonstrating the principle of teleoperation--the control of unmanned vehicles from a manned spacecraft. While this was not necessary for operations on the lunar near side, teleoperation made possible lunar rover missions to the far side, or to other regions that could not maintain a line-of-sight to Earth. It was also during the ILP-5 mission that the LLOP acquired its unofficial call-sign: “Collins Base.”

The second lunar rover mission would go on to prove the utility of teleoperation, when the crew of ILP-7 teleoperated the first spacecraft sent into the Moon’s South Pole-Aitken Basin. Since the Lunar Observer spacecraft had hinted at the presence of ice in the permanently-shadowed craters at the southernmost parts of the immense crater, the focus of engineers designing In-Situ Resource Utilization (ISRU) systems had shifted from baking lunar rocks at immensely high temperatures to the much easier task of electrolyzing water. However, before any of those plans could be brought to fruition, it was first necessary to prove that the ice existed at all. Lunar Rover 2 (dubbed “The Buzz Bot” after the last Apollo 11 crew member, who had not yet had a new vehicle named in his honor) would do just that, providing the first in-situ look at the Moon’s hidden hoard of cometary scraps.
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Real quick-

There was simply no identifiable survivable abort mode in the event of a second-stage breakup; even if the crew pod had the ability to independently reenter the atmosphere, it would have to break its way out of the Lifter II payload bay first,

Did you mean the Shuttle II payload bay? Or is Shuttle II carried in the Lifter II payload bay?
Real quick-

Did you mean the Shuttle II payload bay? Or is Shuttle II carried in the Lifter II payload bay?
It seems clear to me that the Shuttle II rides atop the Lifter II (though a parallel stack would be possible, with all engines burning and the Shuttle II's drawing kerosene and oxygen from the Lifter II tanks). Either way they are separate vehicles that stage together for a time, with the Shuttle either riding atop as a passive payload of the Lifter or parallel burning which would allow the Lifter to have fewer engines and lighten the whole stack a bit overall. Either way in theory if something goes wrong with the Lifter, the Shuttle could peel off and attempt to control its separate landing--either way with the Shuttle having internal tankage, when it separates it is full of propellant not intended to be there when it reenters and lands as designed.

The old Shuttle did not have an escape capsule either, but it had extra engines providing so much emergency thrust that the whole thing could separate from both the Lifter and the second stage propellant/engine stack, and having separated would be no heavier than usual for entry and landing, hence it had a viable escape mode. In theory the OTL Shuttle could drop its external propellant tank and be in the same position, except that first of all, this was too dangerous to attempt while the SRBs were firing, and secondly it was far more massive than the first generation Shuttle of this ATL, so attempting to give it a mode of rapidly separating from the tank would be challenging and compromise its already marginal payload capacity. The ATL design had superior mass budget available and could afford to splurge on such things.

Clearly here, Shuttle II has got an internal payload bay, much as the ATL Sierra second stage or the OTL proposal for Skylon do, and any passengers to orbit must ride in a structure to fill that bay with a habitable module. We saw the idea of incorporating a capsule that could be blown free of the bay and then contemplate entry at orbital speeds considered and rejected.

So what we have here is a design that is inferior even to the OTL Orbiter design. Not by much since Orbiter's OTL abort options were so marginal as to be practically useless, but here there is absolutely no survival mode save riding the Shuttle II to orbit or near orbit, and then reentering. Shuttle II can prematurely separate from Lifter II, at least in theory, if Lifter II can be designed to guarantee shutdown of its engines without blowing it up, and maybe a more robust separation mechanism can be designed that allows forced and rapid separation despite major Lifter malfunction that causes it to ignore engine shutdown commands. (If that were possible, then I suppose it might have been possible to design the OTL Orbiter to rapidly separate from the tank/SRB stack even while the SRBs continue to fire).

Once separated, the Shuttle II is as I said full of oxygen and hydrogen propellant. Having to contain a lot of that stuff it will have a high volume which I think makes it kind of fragile for drastic maneuvers like high-G separation from the Lifter. Unlike the OTL Orbiter, being full of fuel means it has very extensive delta-V available, the majority of the delta-V required.

Recall that the old Lifter is designed to reach separation speeds, with a light upper stack, of I forget how high, 2500-3000 m/sec at most, and then use reserves of ker-lox propellant to brake down below 1500 m/sec so that when it falls back to levels of significant atmospheric density (between 60-70 km altitude) it is only moving at 1500 m/sec, and then aerobrake down to low supersonic speeds where it deploys its jet engines and flies back on their thrust. We are told in this post Lifter II will endure considerably higher airspeeds, twice as fast and thus twice or more the initial heat flux from drag while aerobraking. They said nothing about whether propellant ballasting would continue to be practiced or not. My impression has been Lifter I always did some prop ballasting, even when launching with maximum upper stack load, while the impression I get here is that the largest loads will involve no propellant ballasting. Smaller loads can be launched with propellant ballasting, except that the Shuttle II has got a limited mass range--if its minimum is high enough, there will be no propellant ballasting ever, and the weight range of Shuttle II launches is much reduced, minimum loads being much nearer maximum in absolute tonnage or percentages.

This means Shuttle II can be smaller since it will routinely separate from Lifter II at a higher speed after a longer burn and require less delta-V to reach orbit. Still, we are dealing with hydrogen propellant for the upper stage I believe--conceivably a significant volume reduction is achieved by burning the Shuttle II engines with a mix including kerosene for a while, which I believe trades off Isp for higher thrust and much reduced volume flow rates, though increased mass flow rate.

But upon separation before completion of the Lifter burn, the Shuttle tanks are full and it cannot land that way. It must either burn off the propellant or vent it effectively. For separation near liftoff, I suppose it would be sensible to burn up about 60 percent of the propellant continuing to ascend, probably more steeply than usual, then turn around to do a propellant ballasting burn to use most of the rest up braking and reversing speed to head back to the launch site. Later in the burn it can instead just keep burning to achieve a once-around orbit, or until it has enough downrange to land at an emergency field in Africa, perhaps again relying on excess speed and propellant ballast burning to burn off excess propellant. Venting seems pretty risky to me!

This might seem superior to OTL's Orbiter, which had no more delta-V after separating than its orbital maneuvering reserve would allow, that at low thrust and perhaps useless in the sea level atmosphere. But it depends on the nature of the emergency; with propellant integrated into the hull, there is nothing to be done about engine failure that might cascade if initially undamaged engines continue to burn after perhaps being damaged by the first failure, nothing to be done about losing hull integrity, which with the lightweight propellant containing structure seems more likely to me than damage to the OTL Orbiter or the first generation ATL Shuttle.

Basically the same decision as OTL is being made, something explicitly referred to in the text--"the new Shuttle is so reliable failures will be as rare as with modern certified commercial aircraft!"
I see we're approaching a certain date and year (9/11/2001) ITTL...

Good TL on an alternate transportation system, BTW...
Chapter 20: Landing
“America’s challenge of today has forged man’s destiny for tomorrow. And as we leave the Moon at Taurus-Littrow, we leave as we came, and God willing as we shall return, with peace and hope for all mankind. Godspeed the crew of Apollo 17.”​

Chapter 20: Landing

St. Augustine. Daytona Beach. Edgewater. Constitution devoured mile after mile of Florida beachfront as she dove down to her landing strip at Kennedy Space Center. Carefully, her pilots lined her up with her runway, the 15-thousand-foot Spacecraft Landing Facility, her great rudders easily deflecting the thick, slow air near Earth’s surface. Her jet fuel tanks were far lighter now than they had been at launch, but she retained enough kerosene to make another attempt if the first one should prove unsuccessful, or even to hold, briefly, until cleared to land.

That wouldn’t be necessary today. All air traffic around Kennedy Space Center was clear for her return. Welcome words came to Young and Crippens’ ears: “
Constitution, this is LLF Tower. You are cleared for landing.”

From afar,
Constitution was almost invisible against the blue background of the sky. Between her slightly charred underside and her still mostly-white dorsal surfaces, she blended neatly with the thin haze of the seaside atmosphere. Only as she approached did she grow into a discernible point, and then into a clearly winged shape, and then into a white-colored winged shape.

As she approached for a landing, her pilots throttled her engines back, and traded altitude for velocity for the last few miles of her journey.

From their perch almost on top of
Constitution, Young and Crippen guided her in, flying over the last scraps of wetland before the runway.

As Young throttled back the Lifter’s array of jet engines, a memory of a debate with Deke Slayton as to whether the Space Shuttle should have engines at all came back to him. In truth, despite the decision to go without engines on the smaller craft, Young was perfectly happy to have engines at his disposal on the Lifter. Haise and Truly would have only one shot at their landing, whereas he…

Constitution, Kennedy Tower. We read you go for landing. Do you copy?”

He had a choice. With a single word and a push of his hand, he could throttle back up and send
Constitution around for another pass, going around if conditions weren’t just right now. But he couldn’t do that indefinitely. Some laws could not be broken. Sooner or later, Constitution would finish this journey, and there was nothing he could do to stop that.

Even as Lunar Rover 2 demonstrated the utility of teleoperation, JPL’s engineers were also preparing the next in their long and wildly-successful line of fully automated probes. Following closely on the heels of Cassini, and indeed developed in parallel with the earlier spacecraft, the Le Verrier spacecraft was aimed at Neptune, and lifted off from LC-39B aboard the Lifter Liberty in 2002. A virtual clone of Cassini (most of its instruments being simply copies and spares of those developed for the Saturn orbiter), Le Verrier had in fact been partially completed in 1995, and NASA contingency plans in the event of a Cassini launch failure involved accelerating the spacecraft’s completion and launching it to Saturn in time for the 1997 launch opportunity. As the earlier mission had gone off without a hitch, Le Verrier instead became the first spacecraft launched to orbit an ice giant.

Of the two large planets beyond Saturn, Neptune took priority over Uranus because of its much more visually dynamic atmosphere (with icy cirrus clouds and pale storms and dark, cloudless vortices), which was expected to increase the value of optical imaging of the planet’s cloud decks, and because its large moon, Triton, with a tenuous nitrogen atmosphere and documented surface geyser activity, was much more interesting than any of Uranus’s (apparently) inert, undifferentiated moons. The moon’s retrograde orbit also indicated that it originated outside the Neptune system entirely, suggesting that it originated further out in the solar system (and making it extremely valuable for comparison with Pluto and other outer solar system bodies when data on those came in).

The other major factor that prevented a mission to Uranus was the availability of launch trajectories to the seventh planet. Le Verrier was launched on a complex trajectory highly dependent on gravity assists in the inner solar system. Whereas Galileo had been launched directly to Jupiter and Cassini had only had to fly by the King Planet once to reach Saturn, Le Verrier’s mass and the great distance to be crossed between Earth and the Ice Giants made a winding trajectory past Venus (twice), Earth, and Jupiter both faster and less-demanding on the spacecraft’s delta-v. Unfortunately, Jupiter was uncooperative through the 1990s--there was no apparent trajectory to Neptune for which the giant planet’s momentum could be harvested. Though Le Verrier could, theoretically, have been launched directly to Jupiter and from there to Neptune using the Lunar Transfer Vehicle, such a mission would have added considerable complexity to the mission’s operations near earth and would not have saved any significant amount of time (as the window for such a mission would open only in 2004, for arrival at Neptune in 2020).

The multiple flybys also gave an opportunity to test Le Verrier’s instruments with observations of Venus, Earth, and Earth’s moon ahead of its long interplanetary cruise. In an experiment proposed by Carl Sagan before his death in 1997, the spacecraft searched for signs of life on Earth during its flyby of the home planet, analyzing the atmosphere, surface light absorption characteristics, and radio emissions to determine whether a spacecraft could find definitive proof of life and technological civilization from a great distance. The experiment was a success, with the spacecraft reporting clear signs of molecular oxygen (an unstable chemical that cannot exist in high concentrations without constant replenishment by organisms), an absence of reflected red light (a sign of chlorophyll), and artificial radio waves. The spacecraft also performed a close flyby of Jupiter’s moon Callisto and photographed volcanic activity on Io, and studied Jupiter’s long magnetospheric tail, which the Galileo spacecraft had not been in any position to observe. After that, the spacecraft began the longest leg of its journey--the 14-year cruise between Jupiter and Neptune, during which it performed low-power heliophysics and astronomy experiments and studied the Sub-Neptunian Comet (SNC) Chiron from a great (though still scientifically useful) distance.

Le Verrier and Cassini, between them, represent the greatest triumphs yet for the American unmanned exploration program. Though Le Verrier has yet to reach its target, the smashing success of Cassini hints at the treasure trove of new knowledge it will bequeath to Earth, revolutionizing our understanding of planetary evolution and even the origin of life.

Despite these triumphs by the teams at JPL, it was ILP-6, the first manned return to the Moon’s surface, that attracted the most interest from the public and the most attention from NASA. The last components of the entire lunar architecture, the manned cabin that would be attached to the LSAV to shelter the crew on the way down and the laboratory/shelter module that would be pre-positioned on the surface, had been developed by Johnson Space Center and their prime contractor, Boeing. Delivered to Low Lunar Orbit by a two-stage LTV stack in March of 1999 along with a supply of methane-oxygen propellant for the second LSAV (“Goose”), the laboratory/shelter was very similar to the cabin that would eventually transport astronauts down to the lunar surface. The inflatable cabin was filled to the gills with consumables and laboratory equipment, equipment that would allow the crew of ILP-6 to make a detailed survey of their landing site, the crater Aristarchus. After the LTV second stage delivered the laboratory/shelter to the LLOP, it backed away for a rendezvous with Goose, transferring propellant to the lander before its own return to Earth. Goose then approached and docked with the LLOP, and the delicate dance by which the outpost’s robotic arm attached the laboratory/shelter to the lander began. In a series of delicate maneuvers painstakingly programmed into the arm through the long communications lag from Earth, the arm carefully fitted the cabin to the LSAV’s payload bed. When the latches were confirmed secure, the command to undock and deliver the payload to Aristarchus Base was sent.

After a brief delay, during which the landing computer was rebooted because the altimeter radar began to return nonsensical results, JSC gave the GO for terminal descent, and the LSAV “Goose” began her first descent to the Moon’s surface. Loaded with enough supplies to maintain a crew through the entire two-week lunar day, she plunged down to Aristarchus, targeting the crater’s northern rim, which had the gentlest slope and which was closest to the interesting lunar valleys to the crater’s north and northwest. Using the latest Lunar Observer landing site data, she automatically navigated to the smoothest site in Aristarchus’s debris field--”smooth” being a relative term here, as, in an episode that gave the oldest JSC mission controllers an eerie sense of deja vu, she overflew a great many boulder fields on her way down. Ultimately, though, her landing was just as smooth as Albatross’s landing in the Montes Jura five months earlier, and, though her cameras picked up a few large chunks of anorthosite a few hundred meters away, her autopilot had sent her into a fairly smooth, gently sloping field of dust.

For all the high-technology reputation of the space program, the final leg of the laboratory/shelter’s journey was done with perhaps the oldest machines known to man: rollers. When the LSAV deployed its ramp, the laboratory/shelter simply rolled down, a highly advanced descendant of limestone bricks for the modern pyramid. The cabin had been deployed in an uninflated state, her tough kevlar skin stored within an aluminum shell for now, to protect her from the dust that Goose kicked up as she ascended. Though the first seconds of the LSAV’s ascent were done on a low thrust setting, she still kicked up great airless sheets of lunar regolith, scattered on ballistic arcs for kilometers around. But the laboratory/shelter weathered this storm without difficulty, as the Apollo lunar surface instruments had before her.

With the laboratory/shelter’s successful deployment, Aristarchus was ready to receive its first human visitors. Goose ascended back to Low Lunar Orbit, to her station twenty kilometers behind the LLOP. The more dramatic half of ILP-6 would fall to Albatross, which at that moment was receiving her own fuel load and her own payload: the crew cabin.

The launch of the ILP-6 crew had been a multi-mission affair. In addition to the Space Shuttle Destiny, which launched the crew, their landing cabin, and their Hermes capsule, there were almost a dozen Sierra and Raskat-Groza flights that fueled the LTV stack, preparing the system for departure. With the growing emphasis on refueling in space and reusing hardware, the definition of a “mission” was becoming blurry; gone were the days of single-launch flights to the Moon. Now, the first launch for a mission may take place months or even years before an astronaut strapped in.

At last, the crew of ILP-6--Commander Eileen Collins, LSAV Pilot Charles Precourt, and mission specialists Michael Massimino and Chris Hadfield--was finally launched on May 4, 1999, and performed their Trans-Lunar Injection burn the following day, on May 5. After a 3-day transit rich in television broadcasts to Earth (and the first blog posts written in space, by Chris Hadfield), they entered Low Lunar Orbit, separating their capsule and the landing cabin from the LTV that delivered them. After another delicate dance with the LLOP, as the cabin was moved to the LSAV, which then undocked, turned around, and re-docked to allow crew entry, the four astronauts christened their landing cabin, the one which would be reused for many missions ahead of them and which would open the Moon to repeated, economical exploration and development: Sojourner.

Boarding their newly-christened vessel, the crew undocked from the LLOP and began their own descent maneuvers. Following Goose’s path closely, Albatross, bearing Sojourner upon her back, traced a path south-to-north across the lunar far side, then ever lower, north-to-south, as it neared its final destination. As it approached Aristarchus, the LSAV lit its engines again to come down for a landing in the same smooth field Goose had chosen before. The autopilot had made great strides since Neil Armstrong’s hairy descent to Tranquility Base; neither Collins nor Precourt had to take control of the vessel themselves as they fell to Aristarchus Base.

Soon the great crater filled Sojourner’s forward landing windows, and the LSAV throttled down to deliver her precious cargo to the meteor-blasted lunar plain. As the spacecraft drew nearer to the Moon, the rilles and the other craters slipped below the near horizon, and even Aristarchus ceased to be a bowl and became a cliff, its far edge invisible. The lander’s twin engines soon began to kick up streaks of dust, smoke and steam disturbing this surface for the second time in a month, a brief flash of volatiles amid an eons-long rain of micrometeorites.

Every moment was beamed continuously to TV sets across the US and the world, and Collins’ and Precourts’ voices reached the ears of millions as they counted off the last meters of the descent.

“Fuel is good; thirty seconds to reserve.”

“Radar and LIDAR in agreement; 30 meters.”

“Engine performance nominal; contact in fifteen seconds.”

“10 seconds; no drift.”

“10 meters. Descent rate dropping.”

“5 meters.”



The ILP-6 mission was the first of many, but as ILP's planners were considering where and how the next missions would explore and develop the Moon, by what means they would tame the Moon as their predecessors had tamed Low Earth Orbit and the higher orbits, the writing was on the wall for the launcher which had opened the way for the return to the Moon.

One of the less well-advertised books published in 1998, Hammering the Golden Spike: A History of the Space Transportation System, by T. A. Heppenheimer, marks an interesting milestone in the titular program. Written on a contract from the NASA History Office and released on the twentieth anniversary of the first orbital Lifter flight, the book, covered the STS decision and design process, its testing regime, and its triumphs and shortcomings through the 1980s and 1990s, and was well-received among aerospace historians and history buffs. However, as Heppenheimer himself joked at the “The Space Transportation System at 20” conference at the National Air and Space Museum later that year, a typically extravagant NASA gala featuring pep talks from Administrator Goldin and the crews training for International Lunar Program missions and retrospectives from veteran Lifter and Shuttle pilots, together with guest appearances from Apollo and Skylab managers and astronauts, “it seems a waste to have written the book before the last chapter plays out. We’re not going to have an ‘STS at 30’ dinner--its work will be done by then. I’m still happy to take your money, Mr. Goldin.”

Indeed, one must wonder why NASA didn’t wait for the equally-arbitrary 25th anniversary of Lifter’s first missions, as even by 1998 Boeing had set 2003 as the year for the final Lifter flight. As the situation stands, a second edition, with sections dealing with the wind-down in Lifter’s operations and the debate about the USAF’s efforts to prolong the program, will become necessary by that year, as will sections giving a complete retrospective on the Lifter’s place in the American space program and those around the world. Though Heppenheimer has yet to release his monograph’s second edition, it is worth discussing some of the Lifter’s legacy as the program approaches its end.

From 1978 to at least 1998, the Space Lifter and Space Shuttle were the most visible part of the American space program, piloted or otherwise. With a flight rate approaching 20 per year from both coasts, millions of Americans from all walks of life have made the pilgrimages to Kennedy Space Center or Vandenberg Air Force Base to watch the Lifter take off and return. Millions more, as schoolchildren, grew up with pictures of Lifter launches and photographs taken aboard the Space Shuttle Orbiters in their science textbooks. The Space Transportation System, like Apollo before it (indeed, perhaps even more so as movie budgets and special effects capabilities improved), left its mark in popular culture, appearing in films as varied as the (infamous) Lifter flight to orbit in 1979’s Moonraker and the (extremely loose) 1996 adaptation of The Andromeda Strain, set aboard Armstrong and Spacelab. The Space Transportation System, through its myriad of commercial and government payloads, has also shaped modern life in ways that would have seemed fantastic even in the 1960s, from the Global Positioning System to Geostar’s satellite communications business, which, depending on how cynical the observer, either revolutionized travel for millions and allowed unprecedented connectivity in the shipping industry or dumbed-down navigation while destroying the very concept of “vacationing.”

Perhaps the most divisive part of the Lifter’s legacy, among those who partake in such discussions, is its relation to the earlier Apollo program and to the International Lunar Program. Specifically, should Lifter have been built at all? One one side of this debate are those who insist that the Lifter’s missions to Low Earth Orbit and Geostationary Orbit were an unnecessary detour from the real work of opening the solar system through the Moon and going on to Mars. They point to the Apollo follow-on plans, for dual-launch missions and bases, and say that an early effort to develop the Moon would have been far better for the American space program. While most of O’Neill’s acolytes from the L-5 Society embraced the argument that lower launch costs opened the way to easier development of space, a minority argued that, since government action proved necessary for a return-to-the-Moon anyway, that commercial space operations were, in general, a wild goose chase. The Lifter, they say, was a waste of twenty years until the US redeveloped the capability lost with the end of Apollo (that the fully-reusable International Lunar Program missions each cost about $500 million for at least two weeks on the Moon, compared to Apollo’s cost of $1.7 billion for the Saturn V alone, is an argument most shrug off), or a waste of twenty years that could have been spent developing nuclear thermal propulsion and going on to Mars.

From the opposite side, armchair engineers (and some professional engineers) have pointed to Lifter II and Sierra as proof that a fully-reusable launcher would have been more economical over Lifter’s entire lifetime, and that it wasn’t necessarily beyond the technical capability of NASA’s engineers in the 1970s. They look at the legion of lost Saturn upper stages as millions of dollars dropped into the Atlantic and Pacific oceans, and speculate about how much sooner LTV might have been developed if the Lifter had been fully-reusable from the start, or whether Magellan (whose loss NASA only planned to correct with the launch of Venus Observer in 2004) would have been lost if her upper stage had been a frequently-inspected reusable vehicle. These idealists brush off concerns about the funding actually available to NASA in the early 1970s, and the difficulty of adapting an S-IVB-derived stage to winged recovery (some of them point to Bono’s SASSTO proposal, and to the later success of Sierra, as proof that it could have been done with VTVL technology, an example of the perfection of hindsight). Perhaps they are correct, and that way would have been the better route forward. However, none of their arguments differ from any of those put forth by the original fully-reusable TSTO advocates during the Space Shuttle decision--and all of them failed, not on technical grounds, but on development costs. The Space Lifter was, perhaps, the best that could have been achieved in the climate of the late 1960s and early 1970s.

On the whole, however, the Lifter’s legacy is one of successful trailblazing. The Space Lifter, sooner or later, did fulfill the original goals of the Space Transportation System--a fully reusable transport system to deliver payload anywhere in cislunar space--even if it needed to do so in three phases. It launched the first personal satellite communications service, and the first space station equipped with artificial gravity. It launched the first reusable manned orbital vehicle, which itself demonstrated a great many of the capabilities the new space age would require--orbital servicing, satellite retrieval, regular orbital logistics and frequent rendezvous-and-docking, in-space robotic arm control. Veterans from these programs applied their skills to the new lunar program, with its fleet of serviceable tugs, a logistics station, teleoperated rovers, and robotic arms. The Lifter was behind virtually every big-name American space program from 1980 to 2000.

Perhaps the best measure of Lifter’s success is how quietly it faded out. As public attention shifted to the International Lunar Program and NASA’s planning turned, in the early 2000s, to how the capabilities developed for the Space Exploration Initiative could be leveraged further, the Lifter’s descent into obsolescence as a forest of fully-reusable competitors rose from the launch pads south of LC-39 was remarkably below the public’s radar. When polled, most Americans were not even aware that the Space Lifter would soon be retired. The Lifter faded out quietly, gradually, because none of its capabilities were lost. American crews continued to fly to orbit, the space stations remained serviceable, satellite phones continued to ring, and the work of exploring the Moon was uninterrupted. The Lifter II picked up where its elder had left off seamlessly, as did Sierra and the Lifter’s international competitors. The Space Transportation System had accomplished the objectives outlined by President Nixon in 1972:

“These vehicles will revolutionize transportation into near space, by routinizing it. They will take the astronomical costs out of astronautics. In short, it will go a long way toward delivering the rich benefits of practical space utilization and the valuable spinoffs from space efforts into the daily lives of Americans and all people.”