Right Side Up: A History of the Space Transportation System
- Thread starter Polish Eagle
- Start date
Because the F-1 engine had its role ITTL. It might be less justifiable in, say, Eyes, but that's about five years in the past and to do anything about it now would require rewriting basically the whole TL. However, it is one reason this TL is focusing much more attention on the exact reasoning behind the alternate Shuttle decision. Given that PoD and the selected approach, the F-1's use is sort of inevitable, but we'll get more into that in this week's post.
Patupi's got it. To quote the post: "A particularly revolutionary innovation in this study was the concept of “propellant ballasting.” By carrying more propellant than strictly necessary for lower-end payloads, and burning it off in a second post-staging burn of the first stage, reentry velocity could be reduced considerably for smaller payloads (like those needed to service a space station), extending stage life. Indeed, with sufficient ballasting, a payload of 25 tonnes could be delivered with such minimal heating on the booster that the existing aluminum skin of the S-IC would suffice for thermal protection."
This gets to one reason you might favor a 5-engine with more propellant ballasting (and thus more delta-v after separation and lower entry velocity) over a smaller version with fewer engines or a short-fueled booster: it dramatically simplifies the TPS problem. I think that addresses most of the rest of your post, Shevek, at least what I can without specs.
Who said it had to glide?
Pictures....we want pictures....
Have no fear, both are coming. Images are waiting while Nixonshead is on a well-deserved vacation from the Blender mines, and specs are waiting to be posted until NASA ITTL has selected a plan and rolled it out. Stay tuned!
Well, if it masses in the ballpark of 300 tons after all rocket burns (not to say "dry" because now we need fuel for jet engines) it will need some massive jet thrust installed to stay airborne, whether it cruises back supersonic or subsonic. The latter would probably be best for overall weight and fuel economy and make it more manageable landing. One might get away with less cruise thrust than a comparable subsonic long range transport, but highest thrust is needed for the trickiest maneuver any airplane performs--landing! However I suppose this need not necessarily be thrust entirely from the cruise engines, because you could install an auxiliary rocket. (Even a single F engine would be overkill, though a small LOX reserve with RP could enable the mighty 750+ ton thrust to save the stage from a crash in a dicey situation). So perhaps we can get away with say half the thrust installed in a 747, say two of the same Rolls Royce engines used on early 747s. They can't be installed in underslung pods of course, or can they? It would create drag, and risk ripping the things off, and they'd be exposed to reentry heating, so I would guess they have to be buried in the wing with a lot of ducting, as no doubt Boeing explored for the SST. The engines and perhaps their fuel (which could be RP-1 I suppose, and kept in the main rocket fuel tankage, though that's a waste of money since rocket fuel is an expensive grade of jet fuel) are yet more "dry" stage mass to consider and make it likelier the whole thing is heavier than 300 tons than lighter!...Patupi's got it. To quote the post: "A particularly revolutionary innovation in this study was the concept of “propellant ballasting.” By carrying more propellant than strictly necessary for lower-end payloads, and burning it off in a second post-staging burn of the first stage, reentry velocity could be reduced considerably for smaller payloads (like those needed to service a space station), extending stage life. Indeed, with sufficient ballasting, a payload of 25 tonnes could be delivered with such minimal heating on the booster that the existing aluminum skin of the S-IC would suffice for thermal protection."
This gets to one reason you might favor a 5-engine with more propellant ballasting (and thus more delta-v after separation and lower entry velocity) over a smaller version with fewer engines or a short-fueled booster: it dramatically simplifies the TPS problem. I think that addresses most of the rest of your post, Shevek, at least what I can without specs.
Who said it had to glide?
All right I think I may understand the "fuel ballast" concept after all. I assumed the goal was to guarantee first stage burnout at the same speed and altitude for all launches and thus dead weight had to match exactly, with more or less of it being in the first stage. Now I see this is not the case at all. I suppose that indeed we do wish for the first stage burnout altitude to always be the same, and that the vertical component of velocity should also always be the same, though it too can be arrested after separation. But now my guess is, you load the first stage with maximum propellant in all launches, meaning a fixed cost for every use of the booster. A lighter upper stage would mean that net delta-V at burnout is higher, but instead of following a fixed ascent profile, the lower the all up launch mass was, the more relatively depressed the launch trajectory is--we turn over sooner and faster, so a lower amount of thrust is along the vertical vector, so that it rises to the same height and vertical speed with the reduced mass. But the horizontal integrated component of thrust is greater and the mass is lower so we reach a considerably higher horizontal speed, which saves the upper stage considerable delta-V and thus enables a given mass of upper stage to lift a bigger payload. But we must reserve a portion of the total first stage rocket propellant, since this higher horizontal speed represents a more severe burden on reentry if we just went with it. We could have auxiliary rockets facing forward for braking, but I guess the thing would just flip over 180 degrees to brake hard and fast on its F engines, then flip again to put its airplane vertical axis in line with the line of the trajectory when it falls down to wherever the air is thick enough to provide major resistance, and belly-flop to a suitable speed, low supersonic (and slowing from massive shock wave drag) or subsonic, where the pilots have good control, then nose down into the slipstream for lift and control. This would be the time to start banking to turn back to the base too.
I can see right off Silverbird Calculator is useless for this. SBC, I find, is not an iterative program or spreadsheet, rather it is sort of a multidimensional slide rule calibrated by empirical real world rocket launch data. So I can believe it for the baseline Super-Saturn (that is, Saturn V upgraded with F-1A engines and thus raised 18 percent in overall mass. Standard rocket ascent profiles apply so the empirical data that calibrate SBC are analogous and the result is reliable. Not so at all for any of these Boeing Booster profiles! I think I can reasonably assume the maximum payload launch profile, with an upper stage essentially identical to the S-2 used for Skylab, would be accurate enough, though optimistic since the higher air drag of the wing would slow down the boost phase a bit. But for lower masses of upper stage, the profile would be far off that a straight rocket would use, being depressed.
I've been trying to work it out iteratively but with all the variables and things I don't know it is pretty wooly as well as difficult.
I could try and make some art, if nixonshead doesn't beat me to it first
Nixonshead is definitely better than me, but I consider myself a fairly decent Blender artist.
I'd be interested to know exactly how much delta V you need to spend to slow a craft from orbit to make the re-entry not need heat shielding. Obviously this would vary depending on starting orbit, and I'm assuming it'll be a slow burn (fewer engines firing), or a two stage burn, to put deceleration right up till it starts cutting air, but from a 200Km orbit roughly the kind of speed it needs to shed. It'd help a lot with my own TL to know what you can get away with.
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You have to get down to 1.5 km/s or so, which isn't really an option if you're orbital.
Chapter 2: Rollout
The question, therefore, is, "is there a phasing of the shuttle or, alternatively, a cheaper shuttle that will not reach the very high expenditures in the middle of the decade?"
Chapter 2: Rollout
Chapter 2: Rollout
The rollout between the Booster Processing Facility and the Vehicle Assembly Building was not a high-profile event for any Lifter mission. For this phase of her preparation, Constitution was escorted by only a handful of photography enthusiasts with large tripod-mounted cameras, junior journalists from the Orlando Sentinel, the Huntsville Times, and the Houston Chronicle, and some of the engineers at Kennedy Space Center stepping out of work briefly to watch one of the world’s biggest flying machine drive by. Security guards kept them all at a safe distance as the airport tug pulled her south along the curving road to the VAB. Too wide for the doors at the end of the transfer aisle, Constitution was rolled in through the massive doors on the west side of the building. As the tug pushed the vehicle through a three-point turn to align the tail of the booster with the doors (only the widest, horizontally-opening portions currently open) the onlookers were presented a closeup view of the sides of the vehicle--generally clean, but yellowed and stained in some places from the heat of suborbital reentry. Her handful of admirers saw a vehicle that had already proven herself in tests and in operational missions.
On the other side of the VAB, a narrower shape was being prepared for her own stacking. This one was much more familiar to the Apollo veterans who still made up a large share of the Kennedy Space Center workforce--an S-IVC stage, the stretched descendant of the S-IVBs which had sent men to the Moon. She’d been at the Cape for months, barged in with three identical sisters from California. Rolled in through the south entrance to the VAB, she was thoroughly checked out in preparation for her mission. Her J-2S-2 engine received particular attention, as it had not been test-fired after attachment to the stage--only before, as part of the lot of engines sold by Pratt & Whitney to McDonnell-Douglas. Unlike the RS-ICs, S-IVCs did not receive names, and any battle scars they earned were short-lived, as the stage ended its mission by burning up in the atmosphere over the Pacific or Indian oceans. This vehicle had never flown before.
The third vehicle in the VAB was the most exotic of the three. Sleeker and smoother than the RS-IC, this last one had a black underside, a new tile-based thermal protection system to protect her from the greater thermal stresses of orbital reentry, and a set of Apollo- and Titan-heritage rocket engines on her rear for orbital maneuvers and, if the worst happened, to boost the crew to safety. As her larger cousin had years earlier when she’d first been unveiled, this one had a crowd of admirers eager to snap a picture with America’s newest spaceship. Engineers from both NASA and Rockwell who worked on her at the Cape were joined by busloads of tourists from the Visitor’s Center, bedecked in track jackets despite the Florida heat, though the latter generally remained behind a rope barrier to stay out of the former’s way. Polaroid camera flashes illuminated her from every angle as engineers and technicians checked her even more thoroughly than Constitution. Umbilical cables and air hoses (maintaining a constant positive pressure within the vehicle, to ensure that no contaminants entered) trailed from access panels all around the vehicle.
Unlike the RS-ICs, whose tube-and-wing shape reflected their origins as disposable rocket stages, this vehicle, an Orbiter Vehicle, had a smoothly curving body, with no clear boundary between wing and fuselage--the entire body generated lift. Augmented by sharply-angled control surfaces, this lifting body design gave the spacecraft the atmospheric maneuverability to return to the US from any orbit at almost any time--which was why one of the other Orbiters, still in production at Downey, bore an Air Force star-and-bar instead of a NASA worm.
The Flax Committee’s attempts to hammer out an affordable way forward for NASA must be considered against the backdrop of the budget situation for 1972. The OMB had proposed to reduce NASA’s budget to $2.8 billion for that year, which would have meant the reduction of piloted spaceflight to Apollo capsules on disposable boosters for the rest of the 1970s. Only the timely intervention of Caspar Weinberger and then President Nixon himself kept the budget at a relatively safe $3.3 billion. Before this happened, however, NASA Deputy Administrator George Low sketched out a proposal to replace the Apollo CSM with a manned, engine-less glider, which would have a small payload bay and significant cross-range, allowing it to service NASA space stations and pull off the single-orbit missions so interesting to elements of the USAF. Unfortunately, while far cheaper to develop, such a glider would have been reliant on disposable two-stage boosters, keeping its per-flight costs unacceptably high. The idea did not gain traction within NASA’s leadership, though elements of the Flax Committee were more receptive. NASA’s leadership switched focus back to the winged boosters and large orbiters favored at both Marshall and the Manned Spaceflight Center by this point.
Both of these preferred options, however, came under fire as the Flax Committee systematically dismantled NASA’s entire economic rationale for the Space Shuttle. Even using NASA’s optimistic estimates of $5.5 million to $9 million per Shuttle flight and sixty flights per year (an estimate that one committee member said must have been made “on hemp”), the Committee concluded that the program would still cost the nation more than it saved. Many of the supposed savings came not from the direct savings in launch cost--which by themselves were barely equal to the task of paying off the tremendous development costs even at high flight rates--but instead from the benefits of less-specialized, less-compact, and heavier satellites and space probes which could be checked out in orbit instead of on the ground and use a standard set of structures and systems. However, while the studies depended on such “payload effects” to justify the massive sticker price of the fully reusable shuttle, companies buying or building payloads were less-enthused with the concepts.
The Flax Committee took NASA to task on all these assumptions, criticizing the minimal projected startup costs and the speculative nature of the payload effects. By the time they were finished, the economic rationale for the Shuttle was dead in the water, but all was not lost. The Committee criticized both Mathematica and NASA for neglecting to study (or neglecting to publish) different phased development and interim operation schemes. The prime contractors had all suggested interim options in their reports to NASA and the committee, naturally giving their own preferred options primacy. Each of them offered the chance to reduce the non-recurring development costs of the program, even as the per-flight cost went up, but despite specific requests few had seen intense focus in the economic studies.
Under pressure from the Flax Committee and Administrator Fletcher, NASA set out to rectify the issue. Mathematica Inc. studied different phased development programs in an effort to find one that gave NASA the capability it wanted while fitting under the OMB’s price cap. By October, the company released a new comparison with a much greater variety of options for NASA, ranging from the desired fully-reusable two-stage vehicles to Big Gemini on an uprated Titan III. The most promising candidates on the list, in the opinion of Deputy Administrator Low, were options called TAOS and ISRS.
TAOS (Thrust-Augmented Orbiter System) called for a large Shuttle orbiter with a disposable propellant tank, its own engines, and either pressure-fed or solid rocket boosters, all of which ignited on the pad and fell off in flight. The vehicle was supposed to have a payload bay big enough for all NASA payloads, and for all commercial and military payloads on the drawing boards. It offered the benefit of a reusable spacecraft (in essence, a reusable upper stage) while putting the winged first stage off until the 1980s or even 1990s.
ISRS (Interim Semi-Reusable System) was the exact opposite approach. Combining Boeing’s INT-22 study with Martin Marietta’s and Boeing’s glider studies, ISRS proposed a system with a flyback first stage built using Apollo heritage technology and a new, much smaller Orbiter designed for Space Station servicing. Its main disadvantage was the inability to recover large payloads--while TAOS could land with large and bulky recovered satellites, and recover payloads in the event of an abort, ISRS could not recover any but the smallest satellites, and any loss-of-mission meant a loss-of-payload. However, by keeping an existing liquid booster in production (albeit in a heavily modified form) while also calling for a new orbital spacecraft, ISRS satisfied more of NASA’s internal political concerns--Marshall Space Flight Center was pleased by building on the foundations they had laid during Apollo, while the Manned Spaceflight Center preferred the idea for keeping crew further from newly developed boosters than the TAOS side-mount concepts. NASA overall benefited from the absence of an expensive dedicated naval recovery force, as all components either burned up or flew back to the United States. Very importantly, the development cost of the winged S-IC was only half that of the TAOS orbiter (the glider’s development, drawing as it did on existing X-20, X-15, and lifting body research at NASA, was cheap enough that it fit comfortably into the difference).
With the full two-stage system clearly unlikely to be approved, the fall of 1971 saw proponents for each system bombard NASA’s leadership and the Flax Committee with ever more detailed studies demonstrating the virtues of TAOS over ISRS and vice-versa. Gradually, committee members and administrators sympathetic to Big Gemini and Titan III or still stubbornly clinging to two-stage full-reusability came to one side or the other.
The committee’s discussions ultimately came down to “intangible benefits” and room for growth in each architecture, as well as architecture cost. “Intangible benefits” refers to the research and operational experience value of the architecture--how much the architecture lays a foundation for future development. Despite all the economic analysis, it was still generally understood that the end-game of the Space Shuttle system was a fully-reusable vehicle with “airplane-like” operations that could perform a wide variety of tasks in space. The system that most directly contributed to that vision was held to have superior “intangible benefits.” In this regard, the full-sized TAOS orbiter and the smaller ISRS glider actually had roughly the same value--experiments with satellite servicing and payload bay operations could be performed as well in a 10’-by-20’ bay as a 15’-by-60’ bay, and hypersonic flight data from the smaller vehicle could probably be generalized to the larger one; the ISRS glider provided those same benefits at a fraction of the cost. For larger NASA and USAF cargo missions, the ISRS could be flown without the glider, and would in fact exceed the targets both for mass to orbit and payload envelope. The intangible benefit of recovering a satellite was deemed minimal, as the communications satellite industry itself had previously been found to be lukewarm to the idea. As far as intangibles went, TAOS could not deliver anything to justify its greater cost.
As far as room for growth, ISRS could, at some point, replace its second stage with a fully-reusable Orbiter, as initially envisioned by NASA, while the first stage continued to see incremental development and improvement, eventually yielding the desired two-stage fully-reusable system. TAOS, by comparison, seemed a dead-end, and an expensive one at that. There was no way to make the system fully reusable without a complete rebuild, and to get to the point of partial-reusability, it required gigantic solid or pressure-fed boosters, advanced new cryogenic engines, advances in thermal protection, and a host of other innovations. ISRS, on the other hand, used off-the-shelf engines and operated mostly in a flight regime fairly well characterized by tests conducted with the X-15 in the early 1960s, and a size tested by the XB-70 shortly thereafter. For these reasons, the development cost of the ISRS was only half that of TAOS, while delivering the same per-mission cost savings and equal intangible benefits.
Until this point, the President had been fairly divorced from discussions between NASA and the OMB regarding the details of the program and its required budgets, leaving it mostly to deputies like Fletcher and Weinberger to mediate the details. However, it became increasingly clear that without a direct presidential decision, the Flax Committee might be on the verge of rejecting any of these options or demanding yet more studies, which could in turn halt the momentum which had begun to build for the proposed program. The effects for NASA and for the aerospace industry could be cataclysmic, a fact which worried Nixon for two reasons. As already demonstrated, he had no interest in being remembered as the president who “cancelled the space program,” and had already been willing to step in to arrest the budget’s descent when it seemed it might imperil the operation of the agency’s manned space program. He wanted to give NASA a new grand vision all his own, though one on a budget. In addition, Nixon worried that further delays in the Space Shuttle program and the continued wind-down of Apollo could exacerbate job losses in an aerospace industry already reeling from the failure of the Lockheed L-1011 and the cancellations of the American Supersonic Transport program. With a mind set on taking some decisive action soon, Nixon waded into the details of the program personally in late November, after taking a week to digest the OMB’s summary report.
In this summary report, following a detailed comparison of both systems presented by George Low, the Flax Committee finally ruled in favor of ISRS, with a small 10’ by 20’ payload bay for the glider. The decision to go with ISRS over TAOS was hotly debated, and there remains to this day a small but vocal community insisting that solid rocket boosters or pressure-fed rockets fished out of the ocean would be cheaper than refurbishing the 1950s-designed F-1, while a larger orbiter would have offered substantial benefit from having crew available to assist in satellite deployment. The budget projected for ISRS was within the OMB limits--if barely--and Nixon would be able to offer NASA both its booster and its orbiter. While they might not be the visions which NASA had originally developed, they would be indistinguishable to the public if sold carefully, and offered enough roles for centers and corporations in key states to address Nixon’s other concerns.
This combined program won official presidential approval December 23rd, 1971, with the development of the booster to be included in the FY 1973 budget. The orbiter, whose design had evolved chaotically during the closing weeks of the debate over the design of the system, would require further study before it could be awarded, as would the upper stage which would complete the ISRS, but the program would shortly be on a firm footing to proceed. With the administrative details set, the program was officially rolled out to the public by President Nixon in an early January address from the White House.
“I have decided today that the United States should proceed at once with the development of an entirely new type of space transportation system designed to help transform the space frontier of the 1970s into familiar territory, easily accessible for human endeavor in the 1980s and '90s.
This system will center on two space vehicles. The first, the Space Lifter, will draw on the rich legacy of the Apollo program and will lift payloads to the very edge of space, with the journey to orbit and back completed by the Space Shuttle. 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....
Views of the earth from space have shown us how small and fragile our home planet truly is. We are learning the imperatives of universal brotherhood and global ecology-learning to think and act as guardians of one tiny blue and green island in the trackless oceans of the universe. This new program will give more people more access to the liberating perspectives of space....
"The reason many people fail is not for lack of vision,” said the great American rocket pioneer Robert Goddard, “but for lack of resolve and resolve is born out of counting the cost." Let it never be said that the United States lacks the resolve to lead the world in the exploration and development of space.”
Nixon’s staff had initially chosen the name “Space Clipper” for the program as a whole, with the individual components named “Uranus” (for the booster) and “Argo” (for the Orbiter). Nixon, however, was adamant that the point of the program was to open space to economic development--such poetic names were fine for the glory-seeking days of Mercury, Gemini, and Apollo, but the simpler, utilitarian names captured the everyday nature toward which the program aspired. The launch vehicle would be the “Space Lifter,” carrying the “Space Shuttle” for manned flights, with the two together being the parts of the “Space Transportation System.”
With Nixon’s speech and Congress’s authorization of funding for Space Shuttle development, NASA and its prime contractors had crossed the Rubicon. They had committed themselves to the successful development of the Space Transportation System. Now “all” that remained was to define, design, build, and test the largest and fastest flying machines ever.
Fantastic chapter except:
or at-last pronounce it Oo-ron-uhs...
really Uranus ? poor booster, getting all those joke the Planet with same name has to endure...
or at-last pronounce it Oo-ron-uhs...
yes, RS-1C enter the VAB by High Bays door, because do it wing span and tail fin hight, it not fit the Original gate, build for Saturn V stages like the S-IVB.
the Saturn Shuttle from 2001: A Space-Time odyssey face same problem,
do it's wing span of 133 ft or 40 meters for F-1 booster and orbiter
do better maneuvering the F-1 Booster in VAB, i took V tail fins to limit the hight to 50 ft or 15 meters.
it fit better in high bay and on it's launch pad that move true VAB doors build for a wingless Saturn V
I'm curious how in this TL the RS-1C is looks like and how it's installed on Launch pad.
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In my normal fashion I began a long and speculative reply which upon reflection might better wait on unfolding events. I may go over it and extract some summarized questions or may not. Life events drew me away from a conclusion as yet other questions occurred to me, and here goes with that instead:
I'm wondering now about DoD's involvement in the STS project as a whole and with the Lifter in particular.
OTL as most of us know all too well, NASA, even with the TAOS proposal in hand (the "right side up" option we tend to agree in retrospect should have got more attention instead being left by the wayside, though the author and consultants may know of interesting historical sidebars pointing at it) had difficulty squeezing under OMB's unaccustomed low budgetary bar, and (I may have it telescoped and mangled here) tossed a Hail Mary Pass at the Air Force. Or the Air Force inserted themselves, whatever. The OTL Shuttle Decision did not go forward without Pentagon assistance and advocacy. Believing as I do, or anyway suspect, that the Air Force had the institutional wherewithal to make a serious and honest assessment of the probability that TAOS would actually lower the launch costs enough to justify making a Saturn V sized vehicle to deliver Saturn 1B sized loads despite some obvious aspects of waste, I find it hard to believe the Air Force seriously hoped for greater economics for their payloads. OTOH, within very very broad limits, the military can afford for programs to be gold-plated and costly versus the most hard-nosed economics, and the "intangible" economics mentioned but (in the ATL) debunked by Flax commission and other critics may have had some appeal. What I think explains Air Force willingness to give influential backing to NASA at this point was not the chimerical lure of launch economics but rather the prospect of a manned spacecraft that could also perform aerobatics in the hypersonic regime--a successor of course to the ill-starred X-20, a spaceship with what might have construed by a mind like Curtis LeMay's (long out of the picture himself but surely his legacy lived on in the officer corps) to have the bomb bay he was looking for. In short, that the Orbiter, if you squinted right, could be the Air Force's long lusted after aerospace plane and perform various military stunts. (I've long poured both derision and horror on the instances of such stunts I've heard of, but maybe there would be some others, less useful as trash talk to scare the Russkis but perhaps legitimate in a subtle way as military missions that have been kept quiet and rarely speculated on? In any case the question is, what was the mindset of the Pentagon officials who did back STS in its OTL TAOS form?) In return of course the Air Force added demands to the capabilities of the Orbiter that arguably cost more than the Air Force's advocacy was worth--or if they did in fact enable the program to go forward and STS owed its life to the Air Force, then anyway the cost was still high.
And of course we also know that when push came to shove the Air Force had second thoughts about abandoning their evolved, mainly Titan based for large payloads, capability in favor of total commitment to using STS, and with the Challenger disaster, revived their claim to launch payloads these evolved Titans and other rockets indefinitely, leaving STS's budget without the boost of Air Force purchases of service. Given that the practical launch capabilities of the actual set-up at Canaveral were hardly underutilized, but on the contrary in retrospect were far oversold and straining to keep up with the anemic schedule that became routine OTL, it would hardly seem reasonable to postulate a TL in which the Air Force stuck to the promise to use STS exclusively even if (improbably) NASA evaded a Challenger type loss of mission by sheer good fortune. (Or less improbably though hardly probable, the O-ring fix had been insisted upon from the get-go, perhaps at Air Force behest).
My belief is that the Air Force wanted both the Shuttle and to keep their evolved launchers too. Why not? It's all for defense!
Perhaps under the pressure of achieving the high launch rate laid out in advance on paper, someone might have managed to figure out institutional ways to streamline processing without raising the probability of LOM somehow or other, but this seems a long shot at best, more like wishful thinking. Or if you will, "success-oriented management."
Now that was OTL. But here, with the alternative of "ISRS" on the table and with the Lifter phase of development being projected as significantly cheaper than the TAOS package, and perhaps leaving enough money left over to justify stretching the budget for a much simpler Orbiter as well, NASA has been successfully bludgeoned into considering a path that is within OMB guidelines and thus does not need to call in their big brothers in blue to back them up. The project can stay 100 percent NASA
However, if the Nixon Administration, having coaxed NASA off the ropes the shock of the budget reduction put them on, is committing to purchasing a powerful yet reusable and hopefully economical booster system in the form of the Lifter, would people higher up than the Pentagon perhaps look at the military/security complex launches and wonder, "why not boost them on the Lifter as well?" It would mean procuring more Lifters, or else in essence robbing NASA of some capability developed on its turf to make a "gift" to the Air Force, NRO, etc that they might not even want. But if the argument for the Lifter is that (despite development of a colossally massive first stage structure and prodigal expenditures of propellant) it will overall lower the cost of each launch, why not apply it to national security launches as well?
One very obvious "I'll tell you why not!" explaining a lack of linkage to DoD in this ATL's STS program (which I presume) is that before the system is developed and proven, it would be dangerous to force the Air Force to abandon tried and true launch systems well understood by the airmen operating them in favor of something that might turn out to either fail completely, or at any rate fail of its promise at economics, being more expensive and risky and therefore reducing national security capabilities.
But once the system has shaken down, will the economics be so compelling that it is more cost-effective to abandon Titan derivatives and get on the STS bandwagon? If not so compelling the Air Force itself desires it, then enough to make say Caspar Weinberger, he who was head of OMB under Nixon and to be Secretary of Defense under Reagan, accede to such a proposal in the name of economy? Or indeed given the gold-plated military budgets of the Reagan years, not to supplant Titan but to add to it?
Looking just at the Lifter, the only point in it is to achieve superior launch economics--although another is that with a single type of booster, one can design a wide variety of upper stages to fit on it for various missions.
As OTL, I think what might tempt the Air Force--and get them gumming up the design work in NASA perhaps--is one of the payloads, namely the Orbiter. As with the OTL version making a spaceplane with moderately high hypersonic lift to drag ratio (only 1:1, but for hypersonic entry systems that is fairly high, and the theoretical limit I gather is at most 5:1) mainly for gentler and more flexible reentry profiles also holds out a prospect of something that can do what passes for aerobatics for hypersonic craft.
Thus I suppose the time for the Pentagon to horn in on STS would not be its developmental decade, but the decade it goes at least partially operational, the 1980s. By its nature the Lifter is presumably man-rated, in that it actually requires its own flight crew to operate it, so even before the Orbiter is ready for testing, the Air Force could design their own manned spaceplane to be boosted on the Lifter and a custom second stage. That's probably extravagant even for Pentagon budgets, but anyway the Air Force could take a keen interest in the Orbiter design process and perhaps as OTL influence the product to be more suitable to their own interests, and possibly procure some for Air Force use exclusively.
This is dubious for the same reason X-20 and MOL and Blue Gemini were all cancelled--because generous budgets or not, the Air Force has yet to make a case for any particular military space missions requiring crew.
But Blue Lifters are not so dubious. No one denies the Air Force needs a launch capability, and if the Lifter proves to be even marginally cheaper per launch overall than evolved expendable booster systems, it would be best for the Air Force to procure some for themselves leaving NASA's free for NASA civilian work. Surely the Air Force will also get some involvement in some Orbiter missions, some of which will be classified from beginning to end. But ironically in this TL where the "sexiness" of STS's Orbiter component is deferred and STS as a whole might proceed with no, or anyway limited, Air Force interference, the Air Force may wind up buying in to NASA's design. Conceivably the contractors will wind up making more Lifters for the military than for NASA...
...wild speculations deleted.
It comes down in the end to just how much money per average launch the Lifter boosters will save, all things considered.
One of my earlier postponed remark/speculations hinged on the development of a later generation of smaller Lifters. Much discussion on space threads here asserts that a comprehensive space program can proceed indefinitely with maximum payload to LEO of 30 tons or so; if so, then the 100+ ton maximum payloads one can get from a Saturn V derived Lifter with 5 F class engines is clearly overkill. It may be economic compared even to EELVs to simply underuse the maximum capability of a standard big Lifter with recourse to "propellant ballasting," but surely then it would be more economic still to downsize the booster to optimize for the largest payloads typically demanded, and have just a few big ones on hand for the really big payloads one rather rarely wants to launch. But of course the more we can save per launch, the larger the overall demand for tonnage to orbit becomes and this justifies a somewhat bigger lifter--or even using the full capacity of the original big size by launching in batches.
But any savings achieved by downsizing the Lifters is offset by the cost of a whole new development program. So this evolution would wait for the day the first generation Lifters are nearing their end of life and must be replaced anyway--and it would still be cheaper, in first cost terms, to simply make another batch of the proven design.
I'm wondering now about DoD's involvement in the STS project as a whole and with the Lifter in particular.
OTL as most of us know all too well, NASA, even with the TAOS proposal in hand (the "right side up" option we tend to agree in retrospect should have got more attention instead being left by the wayside, though the author and consultants may know of interesting historical sidebars pointing at it) had difficulty squeezing under OMB's unaccustomed low budgetary bar, and (I may have it telescoped and mangled here) tossed a Hail Mary Pass at the Air Force. Or the Air Force inserted themselves, whatever. The OTL Shuttle Decision did not go forward without Pentagon assistance and advocacy. Believing as I do, or anyway suspect, that the Air Force had the institutional wherewithal to make a serious and honest assessment of the probability that TAOS would actually lower the launch costs enough to justify making a Saturn V sized vehicle to deliver Saturn 1B sized loads despite some obvious aspects of waste, I find it hard to believe the Air Force seriously hoped for greater economics for their payloads. OTOH, within very very broad limits, the military can afford for programs to be gold-plated and costly versus the most hard-nosed economics, and the "intangible" economics mentioned but (in the ATL) debunked by Flax commission and other critics may have had some appeal. What I think explains Air Force willingness to give influential backing to NASA at this point was not the chimerical lure of launch economics but rather the prospect of a manned spacecraft that could also perform aerobatics in the hypersonic regime--a successor of course to the ill-starred X-20, a spaceship with what might have construed by a mind like Curtis LeMay's (long out of the picture himself but surely his legacy lived on in the officer corps) to have the bomb bay he was looking for. In short, that the Orbiter, if you squinted right, could be the Air Force's long lusted after aerospace plane and perform various military stunts. (I've long poured both derision and horror on the instances of such stunts I've heard of, but maybe there would be some others, less useful as trash talk to scare the Russkis but perhaps legitimate in a subtle way as military missions that have been kept quiet and rarely speculated on? In any case the question is, what was the mindset of the Pentagon officials who did back STS in its OTL TAOS form?) In return of course the Air Force added demands to the capabilities of the Orbiter that arguably cost more than the Air Force's advocacy was worth--or if they did in fact enable the program to go forward and STS owed its life to the Air Force, then anyway the cost was still high.
And of course we also know that when push came to shove the Air Force had second thoughts about abandoning their evolved, mainly Titan based for large payloads, capability in favor of total commitment to using STS, and with the Challenger disaster, revived their claim to launch payloads these evolved Titans and other rockets indefinitely, leaving STS's budget without the boost of Air Force purchases of service. Given that the practical launch capabilities of the actual set-up at Canaveral were hardly underutilized, but on the contrary in retrospect were far oversold and straining to keep up with the anemic schedule that became routine OTL, it would hardly seem reasonable to postulate a TL in which the Air Force stuck to the promise to use STS exclusively even if (improbably) NASA evaded a Challenger type loss of mission by sheer good fortune. (Or less improbably though hardly probable, the O-ring fix had been insisted upon from the get-go, perhaps at Air Force behest).
My belief is that the Air Force wanted both the Shuttle and to keep their evolved launchers too. Why not? It's all for defense!
Perhaps under the pressure of achieving the high launch rate laid out in advance on paper, someone might have managed to figure out institutional ways to streamline processing without raising the probability of LOM somehow or other, but this seems a long shot at best, more like wishful thinking. Or if you will, "success-oriented management."
Now that was OTL. But here, with the alternative of "ISRS" on the table and with the Lifter phase of development being projected as significantly cheaper than the TAOS package, and perhaps leaving enough money left over to justify stretching the budget for a much simpler Orbiter as well, NASA has been successfully bludgeoned into considering a path that is within OMB guidelines and thus does not need to call in their big brothers in blue to back them up. The project can stay 100 percent NASA
However, if the Nixon Administration, having coaxed NASA off the ropes the shock of the budget reduction put them on, is committing to purchasing a powerful yet reusable and hopefully economical booster system in the form of the Lifter, would people higher up than the Pentagon perhaps look at the military/security complex launches and wonder, "why not boost them on the Lifter as well?" It would mean procuring more Lifters, or else in essence robbing NASA of some capability developed on its turf to make a "gift" to the Air Force, NRO, etc that they might not even want. But if the argument for the Lifter is that (despite development of a colossally massive first stage structure and prodigal expenditures of propellant) it will overall lower the cost of each launch, why not apply it to national security launches as well?
One very obvious "I'll tell you why not!" explaining a lack of linkage to DoD in this ATL's STS program (which I presume) is that before the system is developed and proven, it would be dangerous to force the Air Force to abandon tried and true launch systems well understood by the airmen operating them in favor of something that might turn out to either fail completely, or at any rate fail of its promise at economics, being more expensive and risky and therefore reducing national security capabilities.
But once the system has shaken down, will the economics be so compelling that it is more cost-effective to abandon Titan derivatives and get on the STS bandwagon? If not so compelling the Air Force itself desires it, then enough to make say Caspar Weinberger, he who was head of OMB under Nixon and to be Secretary of Defense under Reagan, accede to such a proposal in the name of economy? Or indeed given the gold-plated military budgets of the Reagan years, not to supplant Titan but to add to it?
Looking just at the Lifter, the only point in it is to achieve superior launch economics--although another is that with a single type of booster, one can design a wide variety of upper stages to fit on it for various missions.
As OTL, I think what might tempt the Air Force--and get them gumming up the design work in NASA perhaps--is one of the payloads, namely the Orbiter. As with the OTL version making a spaceplane with moderately high hypersonic lift to drag ratio (only 1:1, but for hypersonic entry systems that is fairly high, and the theoretical limit I gather is at most 5:1) mainly for gentler and more flexible reentry profiles also holds out a prospect of something that can do what passes for aerobatics for hypersonic craft.
Thus I suppose the time for the Pentagon to horn in on STS would not be its developmental decade, but the decade it goes at least partially operational, the 1980s. By its nature the Lifter is presumably man-rated, in that it actually requires its own flight crew to operate it, so even before the Orbiter is ready for testing, the Air Force could design their own manned spaceplane to be boosted on the Lifter and a custom second stage. That's probably extravagant even for Pentagon budgets, but anyway the Air Force could take a keen interest in the Orbiter design process and perhaps as OTL influence the product to be more suitable to their own interests, and possibly procure some for Air Force use exclusively.
This is dubious for the same reason X-20 and MOL and Blue Gemini were all cancelled--because generous budgets or not, the Air Force has yet to make a case for any particular military space missions requiring crew.
But Blue Lifters are not so dubious. No one denies the Air Force needs a launch capability, and if the Lifter proves to be even marginally cheaper per launch overall than evolved expendable booster systems, it would be best for the Air Force to procure some for themselves leaving NASA's free for NASA civilian work. Surely the Air Force will also get some involvement in some Orbiter missions, some of which will be classified from beginning to end. But ironically in this TL where the "sexiness" of STS's Orbiter component is deferred and STS as a whole might proceed with no, or anyway limited, Air Force interference, the Air Force may wind up buying in to NASA's design. Conceivably the contractors will wind up making more Lifters for the military than for NASA...
...wild speculations deleted.
It comes down in the end to just how much money per average launch the Lifter boosters will save, all things considered.
One of my earlier postponed remark/speculations hinged on the development of a later generation of smaller Lifters. Much discussion on space threads here asserts that a comprehensive space program can proceed indefinitely with maximum payload to LEO of 30 tons or so; if so, then the 100+ ton maximum payloads one can get from a Saturn V derived Lifter with 5 F class engines is clearly overkill. It may be economic compared even to EELVs to simply underuse the maximum capability of a standard big Lifter with recourse to "propellant ballasting," but surely then it would be more economic still to downsize the booster to optimize for the largest payloads typically demanded, and have just a few big ones on hand for the really big payloads one rather rarely wants to launch. But of course the more we can save per launch, the larger the overall demand for tonnage to orbit becomes and this justifies a somewhat bigger lifter--or even using the full capacity of the original big size by launching in batches.
But any savings achieved by downsizing the Lifters is offset by the cost of a whole new development program. So this evolution would wait for the day the first generation Lifters are nearing their end of life and must be replaced anyway--and it would still be cheaper, in first cost terms, to simply make another batch of the proven design.
Smaller Lifters might be more reasonable down the line, but, as with OTL Shuttle and it's 25-tonne payload, the thinking with RS-IC is that it's better to standardize on one size than to have a mixed fleet with different development programs, and whose vehicles aren't all always amortizing their costs. In other words, an electric motorcycle might be a more efficient vehicle to use when buying milk from the grocery store--but if I already have an SUV, I'm probably more likely to shell out $2.50 for gas than buy a motorcycle.
Again, propellant is cheap--if you're recovering the engines, there's a certain logic to flying with 5 F-1s rather than 3, for those handful of payloads that really need 5.
As to the impacts of cost savings and the USAF's utilization of the unique capabilities of the Flax Glider...stay tuned. The USAF still wants to at least put the payload effects argument to the test, and 40+ tonnes of payload under a 6.6-meter-fairing--I've never heard of an engineer who would refuse payload margin! And once the capacity exists, there's the temptation to utilize it...
Before 1971, though, their involvement in the actual design process is basically as IOTL.
With option of 40 metric tons payload under a 6.6-meter-fairing to Orbit
i know what USAF will say "Shut up and take our money"
On first generation orbiter, who gonna build it ?
Grumman and Lockheed proposed a Lifting body as orbiter during Shuttle design phase
Martin Marietta build for NASA the X-24
Northrop build the M3-F3 and HL-10
The last two were heavy lobbing to get there Lifting bodies space born.
i know what USAF will say "Shut up and take our money"
On first generation orbiter, who gonna build it ?
Grumman and Lockheed proposed a Lifting body as orbiter during Shuttle design phase
Martin Marietta build for NASA the X-24
Northrop build the M3-F3 and HL-10
The last two were heavy lobbing to get there Lifting bodies space born.