Time After Time: Imprints of the Space Transportation System Booster

I'm not a rocket scientist but a lot of actual ones seemed to think it was dangerous, up to and including the NASA Astronaut Office.
Almost all of whom were JSC people, not Lewis people, who didn't know the Centaur hardware nearly as well and seemed to believe balloon tanks were risky despite decades of flight history. I'm not saying there weren't concerns, you can read through them in "Taming Liquid Hydrogen" or in some of those JSC advocates own words here ("Killing “Death Star:” Be persistent in advocating for safe" by Gary Johnson). However, it's striking to me that many of them appear to be more about documentation and testing on an abbreviated schedule, with the concerns about the hardware in general being more based on V I B E S and inter-center politcing.

OV-102 Enterprise as it appeared on the first ever Shuttle flight, completely clean and with white ETs.


OV-099 Independence on its second flight. This mission was a microcosm of the Shuttle program's differences from previous US space programs: it carried the first US woman into space, deployed two commercial satellites, and featured the first use of the retrievable SPAS free-flyer. Booster 604 would be the last one to have stripes reaching into the thrust structure due to heating and refurbishment issues.


OV-103 Discovery on its fifth flight. Besides launching commercial satellites, 51-G also rendezvoused with and fixed the failed Syncom-IV-3 satellite launched four missions ago. Note the replaced D fin and cable tray on Booster 605.


OV-104 Pathfinder on its third flight. Launching Galileo, this was the second Shuttle-Centaur mission, coming mere days after the last that launched Ulysses. Booster 606's LOX tank had been swapped out after a damaging last landing; this was a routine enough occurrence that Michoud usually had more LOX tanks than complete boosters.
You’re not skipping ahead on us,are you? 😉
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OV-102 Enterprise as it appeared on the first ever Shuttle flight, completely clean and with white ETs.


OV-099 Independence on its second flight. This mission was a microcosm of the Shuttle program's differences from previous US space programs: it carried the first US woman into space, deployed two commercial satellites, and featured the first use of the retrievable SPAS free-flyer. Booster 604 would be the last one to have stripes reaching into the thrust structure due to heating and refurbishment issues.


OV-103 Discovery on its fifth flight. Besides launching commercial satellites, 51-G also rendezvoused with and fixed the failed Syncom-IV-3 satellite launched four missions ago. Note the replaced D fin and cable tray on Booster 605.


OV-104 Pathfinder on its third flight. Launching Galileo, this was the second Shuttle-Centaur mission, coming mere days after the last that launched Ulysses. Booster 606's LOX tank had been swapped out after a damaging last landing; this was a routine enough occurrence that Michoud usually had more LOX tanks than complete boosters.
Very nice, I love the effects in the boosters, i can’t wait to learn more about the practicalities and economics of booster reuse .

Is the IUS still a thing ittl? Shuttle-Centaur in 86 means that the Nasa planetary IUS was cancelled, did the USAF one suffer the same fate? There were some serious calls to cancel it when it encountered development troubles irl around 1980 or so.

Glad Shuttle centaur is flying, I do believe it will eventually require mid-ascent fuelling to keep flying after an eventual first shuttle accident. The risks of having it fuelled at launch are too high and were also recognised by the USAF, not just within NASA.
I hope Shuttle Centaur had a successful commercial application, it’ll be the only way for the shuttle to stay competitive in the 21st century.
Adding cross feeds from the External Tanks into the cargo bay does not sound simple or easy while on orbit fueling with hydrogen is a technology that NASA is going to want to develop but also isn't simple or easy. Finally Centaur has a balloon tank meaning the strength comes in part from the pressurisation how it would handle launch while empty with a probe sitting on the top is an unknown question.
I think it's safe to assume that this version of Shuttle-Centaur is closely related to the OTL version, which was a deemed high risk.
It's not as bad as you'd think. Boeing dusted that idea off in the early 2000s and seemed quite confident they could retrofit it into existing Orbiters (though STS-107 means we never got a chance to see)--the change by then being that they wanted to load the tank only after SRB separation. The Orbiter, after all, already has most of the plumbing for running propellant from the external tank, and even IOTL carried smaller amounts of cryogenic liquid in the payload bay (Extended Duration Orbiter).
Act 2 Chapter 4: 80s civil and commercial spaceflight; Mir

Act 2: The Dream is Alive

Chapter 4: “All Over the World”

WALTER CRONKITE: Now Solar Max's circuits are checked out, and the Goddard engineers make certain that it works perfectly. T.J. holds it facing the sun until its batteries are recharged. Then, gently, he returns it to orbit.

[Footage from STS-41-A] TERRY HART: And we have release.

CRONKITE: As Independence and her crew pull away, they leave behind vivid proof that we can work in space. This repair is only the first step; already, people like you and me are beginning to travel into space. Some of our children will live in space, and their children may even be born there. Soon, we will use the Shuttle to build a space station in permanent orbit, operated by international crews.

CRONKITE: Floating free, we look back at the majestic panorama of Earth: our home. Like Columbus, we dream of distant shores we've not yet seen. Now that we know how to live and work in space…we stand at the threshold of a new age of discovery.


– Excerpt from the 1985 IMAX feature “The Dream is Alive”, narrated by Walter Cronkite


While Europe had been devastated by World War II, and remained fractured by the Cold War, it had rebuilt under these circumstances admirably. Although it was practically impossible to match the industrial capabilities of the new world powers within the short span of twenty years, there were hopes that the continent could make its own forays into the field of space. These efforts were spearheaded by France, which wanted to reclaim its former place (or some semblance of it) as a world power.

Under the growing ideology of internationalism in Western Europe, and with proof of collaborative success in other scientific endeavours such as CERN, the European Space Research Organization (ESRO) Convention was drafted in October 1961. When it came into force in 1964, formally acknowledging the ESRO’s existence, it encompassed 10 nations. All of these participated in the Commission Préparatoire Européenne de Recherche Spatiale (COPERS) conferences in early 1961, which examined considerations needed for such an organisation.

For the next decade, ESRO was responsible for most Western European space science endeavours, with instruments launched aboard member nations’ sounding rockets, and later indigenous orbital satellites borrowing launch services from the US.

In 1973, NASA approached the ESRO for possible collaboration in the upcoming STS program. After discussions, it was determined that Europe could make contributions worth at least 10% of the STS' cost. Advisory committees identified actions Europe was taking, and could continue in an increased capacity to make that contribution: build part of the Shuttle, develop the Space Tug, or provide the ‘Sortie Can’, a pressurised laboratory in the Shuttle's payload bay. The ‘Sortie Can’ was required, as the Shuttle had transformed from a mere orbital truck to the only crewed spaceflight component. With financing a space station being an increasingly untenable position, the Shuttle would also have to fulfil the role of an orbital laboratory, and its crew space would neither be sufficient nor optimal for the expected diversity of experiments.

While such collaboration fell in line with the Nixon Administration’s ideal national image, some voices on the American side objected to any European involvement in the Shuttle. First, there was the issue of dependence: Europe's preferred contribution was the Space Tug, which would have to handle all payloads to geostationary orbit, including DoD ones. Despite the Space Tug being increasingly unlikely to get domestic funding, putting a foreign actor in such a vital logistic chain was even more unthinkable. Secondly, giving away hard-earned spaceflight expertise would give Europe a head start in competing with the US in space endeavours and future space commerce. This was particularly acute if Europe built part of the Shuttle, as the resulting information exchange would allow them to glean their way to high technology; this option could also jeopardise the Shuttle if Europe pulled out. Finally, some thought that NASA was using international cooperation as collateral for funding, for it was internationally preferable to fund something to completion than risk losing face by pulling out, regardless of how much would be spent.

That left the Sortie Can for extracting an image of internationalism with the smallest sacrifice; it was relatively independent of the Shuttle and US interests, and also much cheaper. The Americans thus vetted down the options, and presented this singular offer to the ESRO.

Europe accepted. Later named Spacelab, this science suite would consist of three adaptable parts: pallets, used to hold and provide common interfaces for exposed experiments; a pressurised Habitable Module for the crew to conduct investigations and house experiments that need to remain inside, and a smaller cylindrical module, later called the ‘Igloo’ due to its thermal protection covering, to house controls for the pallets if a Hab is not present. In exchange for providing Spacelab, European astronauts would be given seats on the Shuttle. All of them would fly as a new type of astronaut, the Payload Specialist; these individuals are assigned only for their ability to accomplish certain mission objectives, and are not permanent members in the NASA astronaut pool.

While construction uneventfully started on Spacelab in 1974 at English, French and German contractors, the current European space efforts were beginning to show a variety of institutional problems. Within ESRO, there were issues with diverging interests, an inability of dreams to be based on technical reality, and a feeling that a few core members were the ones really running the show. Elsewhere and more significantly, the European Launcher Development Organization (ELDO) failed to deliver an operational launch vehicle. ELDO was even older than ESRO, having come into being in 1962, after Britain wanted to cut losses in its redundant Blue Streak missile by joining forces with other countries, to incorporate the Blue Streak into a collaborative launch vehicle. To address these issues, ESRO and ELDO were merged into a new organisation in 1975, the European Space Agency (ESA). Spacelab was inherited by ESA, under which it would be realised.

Through ESA, Europe also created its own orbital launch vehicle, the hypergolic and hydrolox-fuelled Ariane series. The Ariane program aimed to end Europe’s dependence on the US for launch capabilities. The first version, Ariane 1, made a successful maiden launch in 1979. To capture the largest market sector, Ariane 1 was sized to lift 1.9 tons to geostationary transfer orbit, which was the orbit and mass range most commercial satellites occupied. Moreover, Ariane 1 could carry multiple payloads in one launch with a special adapter, making it even more appealing for satellite constellations. Combined with national subsidies, this launcher would have a temporary near-monopoly over the launch market, before the Shuttle entered service to compete in the same niche.

The US soon realised that it was unable to contain the European space industry’s growth without harming itself. Thus, it gradually reversed its protectionist policies throughout the 1970s. Domestically, it now aimed to make sure it could compete with Europe. Internationally, it spearheaded legislation to prevent Europe or anyone else from gaining an unfair advantage in the new business of space.


Pieces of the Spacelab program first flew during the FMOF flights; one pallet was carried on STS-2. The habitable lab would only make its debut on STS-9 in October 1983, flying aboard Enterprise with Mission Specialist Ulf Merbold, the first of the ESA exchange astronauts. Following the landing, Enterprise was taken out of service, to be modified to incorporate improvements deemed possible after the first flights. With OV-103 still months away from completion, the Shuttle fleet once again dwindled down to one orbiter.

Thus, the period between October 1983 and early 1984 was Independence’s time to shine. Having been converted from the STA, Independence debuted on STS-6 in January 1983 [1], and would be flown almost consecutively for a few missions afterwards. This effectively stress-tested the Shuttle’s turnaround capability; at its peak, Independence was launched 1½ months after a landing. It also racked up many firsts for the US space program; STS-6 deployed the first TDRS satellite, a building block for NASA’s own relay satellite system, and hosted the Shuttle program’s first spacewalk. STS-7 carried Sally Ride, heralding an era of access to space regardless of identity. On this front, NASA’s new astronaut corps, Class 8 (Thirty Five New Guys) and Class 9 better represented the US’ demographics than the crew-cut male test pilots that preceded them.

The new era’s spacefarers were also dressed for spaceflight very differently. With the Shuttle operational, the SR-71 derived ochre launch and entry suits were dispensed with. Instead, all crews wore a blue shirt-sleeve coverall starting with STS-5, with a LEVSA helmet for an emergency air pack to function.

OV-103, christened Discovery, was soon delivered in early 1983. It was built to be lighter [2], with refinements deemed possible using FMOF data. This, along with a 1 second specific impulse increase in the J-2S engines delivered with it, gave Discovery a greater payload capacity than the other two orbiters. Discovery made its maiden flight on STS-41B in July 1984, joining Independence in delivering payloads to space.

41B should have been rightfully called STS-14 (actually the 12th flight, due to cancelled missions). However, the Shuttle mission numbering system was changed after STS-9; instead of straightforward numbers, missions would be denoted using a three-place alphanumeric code. The first digit would represent the year of a decade; the second would represent the launch site (1 for KSC, 2 for Vandenberg); the last, a letter, would represent the order in which the flight's mission plan was drafted for the year.

Soon, these letters began appearing out of alphabetical order due to processing delays, scrubs and reschedulings. Shortly thereafter, the first digit began bleeding into the next year. The Shuttle only managed to fly 4 times in 1984 and 9 times in 1985; while an impressive metric by Apollo standards, it was significantly less than what was outlined when the Shuttle was declared operational, and a far cry from the assumptions used in the 1970s economic studies. People stopped speaking about running out of letters; the Shuttle could not meet the expected flight rates, as there were too many bottlenecks in vehicle processing. Although many improvements were made throughout 1984-1985 as more facilities reached full operational status, orbiter processing time would soon plateau, and remain the limiting factor for flight rate. Expectations are changed accordingly to 10-20 flights per year, although this did not mean that NASA ever gave up on the fight for higher flight rates.

OV-104 Pathfinder was delivered in 1985; it was the last complete orbiter NASA could expect in the near term. It was decided in August of 1982 that the Shuttle program only needed four orbiters to reliably serve all national space launch needs by 1986. While deleting a fifth orbiter completely saved costs now, it would incur additional costs in the future; if orbiter processing rates did not improve, a fifth and sixth orbiter would be needed by 1986 and 1990 respectively, which meant reactivating the Rockwell production lines and logistics chains at great expense. It was thus decided to leave the fifth orbiter as an option; Rockwell’s Downey factory would produce a complete vehicle as unassembled structural spares, before closing down Shuttle production.

The boosters were another story, due to their relative cheapness and short design lifespan of 8-15 flights. The wear and tear incurred with each ocean recovery made frequent replacement a worthwhile tradeoff. Thus, Boeing was to supply one new booster approximately every nine months, in time to replace the oldest fleet member. Retired boosters would then be used as a source of spare parts. While in operational capacity, the fleet of six boosters would be scattered throughout the country; most would be stored at the KSC in the dormant VAB high bays, or be refurbished between missions at the newly built Booster Storage and Processing Facility (BSPF). Simultaneously, at least one would be at Michoud for a 6-month rebuild scheduled after every fifth flight. The operational boosters would be stored and processed under the same roof as the production lines for new boosters and ETs.

With the Shuttle’s lacklustre flight rate, ET production was intentionally slowed to avoid an excessive surplus of tanks. As for the boosters, current refurbishment times and fleet size ironically sufficed for the readjusted flight rate expectations; it was only foreseen to become a real problem when NASA strives for more than 20 flights per year.


Various commercialization policies enacted under the Reagan administration, through the newly established Office of Commercial Space Transportation (OCST), helped the commercial satellite market grow, and ensured a steady stream of payloads for the Shuttle. The last two years of operation saw around five commercial satellites launched from the Shuttle per year, which was comparable to Ariane’s tally in the same period. This demand was significantly smaller than expected, intensifying competition.

Ariane and Shuttle also shared a market with ELVs from the US. Companies such as General Dynamics, Martin Marietta and McDonnell Douglas leveraged their formerly nationally operated rockets to provide similar services. However, as government procedures and facilities were still significantly involved in a satellite ride, these companies had to provide their services through a quasi-governmental approach. This added paperwork and scrutiny, making any launch sale an expensive hassle, and profit margins slim.

Startups, such as American Launch Services (ALS) with their Percheron and Conestoga rockets, were also subject to the same tedious regulations. But they did not have the capital to survive non-profitability; in the case of ALS, they merged with other companies, before being done in by failed maiden launches in the 1990s.

The Shuttle was also not as profitable as expected, as it turned out to be much more expensive to fly; this was a mathematical consequence of its lacklustre flight rate. For example, the Shuttle flying just 9 times in 1985 meant amortising non-recurring costs over fewer flights, pricing each of the launches at around $200 million (1985 dollars). Estimates with “operational” flight rates of more than 15 launches per year yielded a better, but still high $140 million per flight. [3]

Thus, to permit market participation, non-recurring costs of Shuttle were subsidised by the government, limiting the amount passed on to commercial launch prices internally decided by NASA. This brought the prices to lows of $85 million per flight, amortised across co-manifested payloads according to how much mass and volume they take up. Ironically, this clashed with policy goals outlined in the 1982 Commercial Space Act; the sought after free market competition never materialised, as the Shuttle’s subsidised prices to compete internationally destroyed any hope for domestic entities to step into the market. But neither was raising the price an option, for analysis showed that customers could simply flock to the cheaper Ariane, instead of the nascent US ELV market. Worse, Ariane was tailored to commercial needs, instead of being ICBM-derived and pressed into such a role.

Ariane's success was seen as a sign that US commercial spaceflight was doing something wrong. Criticism of using the Shuttle as the sole US launcher grew, mainly in the Department of Transportation (which in 1985 had yet to hold complete regulatory power over commercial spaceflight). They argued that with current market demand and launch rates, funding the development of a modern ELV would be cheaper and more profitable in the long run. They also argued that splitting the Shuttle pie would actually rejuvenate the domestic space launch sector, which was struggling to compete with both Europe and NASA. Fewer commercial customers would also reduce the pressure on NASA infrastructure, allowing them to focus on missions that truly needed the Shuttle's unique capabilities.

In response, NASA tried to argue that the Shuttle could be more efficient and economical with higher flight rates, if they were just given the resources to attain them. With demonstrated turnaround times and some extrapolation, a four-orbiter fleet was deemed able to fly anywhere between 18 to 26 flights per year; lower rates would cause the per flight costs to balloon, while higher rates were unachievable unless more facilities were activated. Adding a fifth orbiter and more boosters could also increase the maximum rate to 32 per year, but as with opening new VAB High Bays, nobody on Capitol Hill wanted to cough up the money for another $1.7 billion orbiter, and additional S-1Ds at $35 million (more with associated facility expansion costs) each, once booster processing became the limiting factor.

The conflict was later resolved in NASA’s favour. Commercial satellite launches on Shuttle would continue to be sold, but according to prices determined through auction, and thus “market forces”. The point of contention now was how low the auction prices should be allowed to go; with overwhelming support from all agencies except for the DoT, the lower auction price floor of $80 million per payload was selected. These rules were signed into law in July 1985, giving free rein for the Shuttle to compete with Ariane. While the development of domestic ELVs would suffer greatly under this policy, it was not a major consideration in the decision.

The higher than expected costs of commercial spaceflight were not isolated to the Shuttle. A prime example of this was the Industrial Space Facility, a concept for a modular Shuttle-serviced orbital factory, advocated by Space Industries Inc (SSI). The inherent expenses and risk of investment forced SSI to seek out government users, which would guarantee a basic level of income regardless of their commercial relevance. The OCST thus insisted NASA to look into the ISF; NASA initially agreed, but in 1986 began to seesaw over the decision due to the ‘threat’ the ISF could pose to plans for a national space station, as the substantially cheaper (and thus more functionally limited) ISF could be used to argue for the station’s redundancy. But ultimately, the space industry economy simply wasn’t as big as imagined; many technologies once thought to require microgravity were proven to be workable on Earth. Moreover, ISF’s concept was limited by space access; the actual flight rate and cost per flight of all space vehicles were a very far cry from what the ISF needed to make economic sense. The ISF effort would wither over the next decade, despite influential supporters such as capsule designer Maxime Faget. The demise of ISF was but one symptom of the space investment bubble bursting. However, the Shuttle that initially inflated it would continue with business as usual.

With the Shuttle constantly launching satellites for various purposes, an increasing amount of civilian technologies, most notably communications, now depended on space. But despite this abundance of civilian applications, the Reagan administration felt that more had to be done for space to truly be visible as a realm of everyday life. Namely, everyday people would have to fly there and back safely.

In 1984, the Teacher in Space project was announced. Applications were sent to over 40 thousand schoolteachers around the country, and the 11 thousand who responded were vigorously vetted. Emerging from the ten finalists was high school history teacher S. Christia McAuliffe, and her backup, elementary school teacher Barbara R. Morgan. The following year saw the similar Journalist in Space project, culminating in legendary Apollo anchorman Walter Conkrite being slated for a flight sometime in late 1986. However, the first US “civilian” to fly in space preceded finalists from both projects: Utah Senator Jake Garn flew on 51-B in early 1985, although it can be argued otherwise with his significant piloting experience during his time in the Utah National Guard.

Come 15 January 1986, McAuliffe flew to space as part of STS-51-J’s seven-person crew aboard Independence. While in orbit, she gave two lessons that were televised to children around the country and globe. The mission also deployed the second TDRS satellite, and inaugurated LC-39B, which just finished its conversion to Shuttle configuration last December. Independence returned safely to Earth seven days later.

1986's commencement also saw Enterprise returning to service on STS-61B, staying in orbit over New Year's. With a full fleet finally available, the Shuttle had better chances of meeting the 1986 manifest of 16 launches, a much more realistic expectation.

And for the first part of the year, things were mostly on track to achieve this goal. 1985 and 1986 were thus sometimes retroactively regarded as the years in which NASA truly started mastering the Shuttle. NASA was learning and inventing new ways to get things done on time, in response to avionics gremlins, fuel leaks, payload issues, and other technical reasons that continued to jostle the schedule around. Using the MSS, a problematic classified payload could be switched for a civilian Spacelab right on the pad; extensive booster rebuilds, usually undertaken every five launches, were occasionally delayed by one flight as they proved more resilient than thought; ‘wet’ prelaunch dress rehearsals were abandoned entirely; parts were cannibalised from orbiters flying later in the launch manifest to make up for shortages; missions flew with redundant systems alone, while failures of noncritical main systems were waived from repairs; the mission before 51-J was even cut short by days to allow the next one to fly. All this reshuffling was meticulously tracked down with improved change control records. With these approaches, people were confident that the months-long standowns experienced in 1984 and 1985 were a thing of the past. A NAR manager later remarked in an interview that “an unsaid goal of the Shuttle program in 1986 was to not let a -6 fly in 1987.” [4]

In the midst of these successful gambits were a significant number of close calls, most involving the fragile heat shield. Missions returned with all manner of projectile damage, ranging from scratches to missing tiles, caused by anything from ET foam to wastewater icicles. This incredible survival rate can be attributed to the fact that no damage ever occurred to the underbelly, where the heating was the most severe. Statistically, the OMS pods suffered the most, followed by the payload bay sides and wing upper surfaces; thankfully, these are also the regions where tiles are being swapped out for Felt Reusable Surface Insulation (FRSI) blankets, which are much more resilient and easier to maintain. This change to FRSI, like many other modifications, was procedurally implemented on the orbiters during their post-flight refurbishments.

The digital avionics also continued to cause issues. During STS-61-D’s lifting reentry, outputs from two of the four main flight computers diverged. Due to the ‘voting’ system, had one more failed, the pilots would have needed to immediately press a red button on the joysticks to switch to the backup, as all four disagreeing would result in a loss of flight control. The problem was eventually traced back to Pathfinder’s lower equipment bay: ratty inputs were sent through faulty wiring abraded by an overtightened screw. Such translations of hardware issues to software faults would continue to occur throughout the Shuttle program, although the quintuple redundancy inherent in the avionics usually prevented things from escalating.

Then there were the outright failures and equipment losses, most notable of which was the destruction of Booster 604. After boosting STS-51-I, one of the GOX vent valves came unseated upon parachute deployment, causing the LOX tank to lose pressure. Without the proper forces acting from inside the tank, it instantly crumpled upon water impact, leaving the remains of the stage sitting engines-down in the ocean. What was left of 604 was recovered, and its salvageable parts were reused as structural spares or in the under-assembly Booster 610. Recovering 604’s remains also became the purpose-built MV Space Clipper’s first assignment; the obsolete Catamount was replaced by the much more modern and manoeuvrable Space Clipper in a move to save recovery costs. The valve would be redesigned to avoid a repeat incident. On the bright side, this incident validated the decision to have six operational boosters, as the schedule absorbed the loss without a hitch.

Yet, these mishaps were barely apparent on the outside, and to many within the space agency’s management. To them, the Shuttle’s operation just became more routine as more time went on, and more missions were flown.

Hughes HS-376 satellites, built to a standardised design and sold to a wide variety of groups (some changed owners while waiting for launch, typical of the immature market), spun out of sunshields, attached to PAM-S kick motors for a boost to GEO. GAS cans flew by the dozen, carrying experiments that had sizes and budgets too small to justify dedicated platforms. The TDRS network became increasingly functional with each satellite added, eliminating communication blackouts for NASA missions, while replacing expensive tracking stations and ships.

Uniquely configured Spacelabs stayed on orbit for weeks, with the science missions' relatively large crews (STS-51-I, flying Spacelab Mission D-1 in October 1985, set a single-vehicle record with its 8 person crew) running experiments on schedule. Despite being nowhere as long, these long duration missions benefitted from and built on knowledge gained during Skylab missions, in enabling groups of humans to work productively in space.

At the same time, Payload Specialists, originating from various nations allied with the US, flew aboard the Shuttles. Many European nations, and others such as Mexico, Saudi Arabia, and Indonesia, had their first spacefarers carried to orbit through these initiatives. These Payload Specialists often accompanied their respective nations' first satellites. Most non-ESA 'exchange astronauts' were the culmination of bilateral diplomatic agreements. For the others, as of 1986, the US had extended many more of these to the international community; talks were underway with China and Japan for their astronauts to ride aboard the Shuttle. [5]


The American practice of international Mission/Payload Specialists was in some ways similar to the Soviet Interkosmos program. Interkosmos had been around since 1967; while it had similar purposes of promoting international space collaboration, and the political goal of consolidating a sphere of influence, Interkosmos greatly differed in its scope.

Interkosmos consisted of both crewed and uncrewed collaborative missions; it was the USSR’s only institutional gateway to international cosmic cooperation. Assistance for uncrewed endeavours was offered through expertise, funding and launch services, allowing non-spacefaring nations to have their own space experiments or artificial satellites. The experiments were either carried aboard dedicated Interkosmos satellites or Vostok-derived Bions, the latter of which had a pressurised environment for biomedical investigations. In the spirit of space collaboration, the services were open to all countries; notably, US scientists flew experiments on almost all of the Bion satellites.

The crewed program also differed slightly; although most participants originated from communist and non-aligned states, citizens of capitalist countries, most notably France, did sometimes fly on such missions. Owing to the Soviets’ well-developed long duration spaceflight abilities, the Interkosmos flights were all visits to space stations. The earlier missions were hosted by Salyut 6 and 7, the country’s first modular stations constructed from DOS and TKS modules. The Interkosmos cosmonauts’ Soyuz rides were expected to be complemented by the Buran once it started flying; although the TKS/VA spacecraft was currently available, there was neither pressure nor universal support to bring it into crewed service.

Instead, the space program’s priorities lay with realising Buran, its associated rocket, and the YMOS as soon as possible. Either project often ate into the other's budget, necessitating work stops every now and then throughout the early 1980s; the YMOS was affected more due to Buran's relevance to national security. At the same time, Buran was lagging behind more severely; the original optimistic launch date of late 1983 slipped, first to 1985, then beyond. While there were no fantasies about it being easy, the mechanical and electronic complexity of the spaceplane and its launcher made engineers wonder how the Americans were actually coping with the Shuttle’s increasingly routine operation.

The first full-size Buran took to the skies in 1985; unlike Constitution, OK-GLI flew under jet power from four Lyulka AL-31 engines, which would also be included on the operational model for go-around capabilities. Built-in jets were required, as the Soviets did not have a big enough aircraft to carry it aloft. But like its Shuttle equivalent, OK-GLI was missing many of the systems necessary for spaceflight. Additional non-airworthy airframes also played their part in finalising the structure and testing out logistics systems. Thermal protection and the novel wing-folding mechanism were tested using BOR-5 vehicles lofted throughout 1984 to 1986.

On the launcher side, the RD-170 had decidedly been the source of problems; with its immense, barely contained power, a test stand explosion sent pieces flying 4km away. Things came to such a head that the N1’s NK-33 power plants were seriously considered as an alternative, despite the embarrassing reversal of decisions that would entail. Another approach involved developing the MD-185, an engine with a quarter of the RD-170’s thrust. However, these ideas were dismissed, as they would have potentially further prolonged the program.

As the engineers’ hard work would have it, both the RD-170 and the RD-57 were certified for flight in mid-1985. The engines first went on the 11K77 monolithic launcher, now renamed Zenit (“Zenith”). Capable of carrying 20 tons to LEO from Baikonur’s Launch Complex 45, this vehicle directly rivalled Chelomei’s Proton. The Zenit first launched on 13 April 1985 with a mass simulator; the second stage’s nozzle extensions were blown apart during hotstaging, critically reducing the engines’ specific impulse and causing the mass simulator to fall short of orbit. The nozzle extensions would be deleted for all Zenits thereafter, at a bearable cost to specific impulse. The second flight in June fared no better; one of the second-stage engines failed shortly after ignition, sending the vehicle into a destructive tumble. While this level of reliability was typical of all Soviet launchers during development, the Zenit would appear disproportionately terrible when compared to other 1980s launchers. Zenit would finally score a tentative success on its third launch, in October 1985. A few more test flights would follow, with mixed success; failures were no longer due to propulsive components shared with the 11K25.

By early 1986, the 11K25 had also completed its final tests. With the successes of fuelling and firing tests with vehicle 5S, it was decided to turn test airframe 6S into the first operational vehicle, 6SL. The original plan to expend 6SL on a boilerplate Buran was also changed, and it was instead flown in September 1986 with a military payload. [6] With the 11K25 separated from the Buran program, it also needed a new name; the type became Energia, taking after the organisation that built it.

The success of the 6SL launch in September 1986 proved the Energia’s reliability, and cleared the way for the first YMOS to launch on Energia 7SL. Had the launch still failed, the structurally complete YMOS-2 would have (hopefully) been flown as the replacement at a later date, with little mention of the first. Owing to YMOS-1’s meagre 50t mass, 7SL would use only two strapon boosters around the core, along with an under-fuelled (by 50t) upper stage with six out of eight engines installed.

On 12 October 1986, Energia 7SL lit its three first-stage engines, and ascended from the former N-1 launch complex. All RD-170s performed as expected before falling away; the side boosters were jettisoned 2 ½ minutes into the flight. While there had been plans to demonstrate recovering them on this flight, this was put off to the next due to budgetary issues. The expendable core throttled back up after booster separation, using up the fuel it previously conserved to outlive the boosters. The only problem throughout this launch arose after Stage 2 ignition, when one RD-57 engine exhibited reduced performance; it soon resolved itself as the burn continued.

Upon shutdown, YMOS-1, now COSPAR 1986-085A, was safely in a roughly circular 360 km orbit, with an inclination of 51.6°. It was the second heaviest and the largest monolithic object the Soviet Union launched to date. The module oriented its longest axis perpendicular to Earth, taking advantage of gravity gradient stabilisation to conserve attitude control fuel.

The first crewed mission to Mir launched on 7 November 1987, in time for the October Revolution anniversary; Soyuz TM-2, flying Mir Expedition 1 [7], was crewed by Aleksandr Serebrov and Vladimir Titov. Autonomously guided by the new Kurs rendezvous system, the spacecraft successfully docked to the YMOS nadir (Earth-facing) port, axially fitted to the module's three-port hub.


Once onboard, the two crewmembers activated the station, and unpackaged the 4t of cargo that was launched along to make better use of the Energia’s capabilities. They would spend a total of three months aboard the YMOS, putting various systems through their paces, and carrying out astrophysics experiments using the UV and X-ray sensing instruments aboard. Soyuz TM-2 then returned to the steppes of the Kazakh SSR, carrying the two men and a TM-3 crewmember, Syrian Interkosmos cosmonaut Muhammad Faris. TM-3 had arrived a week before the departure of TM-2, for a smooth changeover of command.

Mir was expanded in December 1987 with Kvant [8], a TKS-derived module. Kvant was launched aboard a Proton rocket, and flew itself to Mir. While it initially docked to the axial port on YMOS-1’s hub, the Lyappa arm was used to move it to the 'top' (with respect to the YMOS' pitch axis) port. Besides adding more astrophysics experiments and an airlock, Kvant would be Mir’s primary guidance and environmental control unit, to conserve equivalent systems on the less fungible core modules. Its solar panels would also provide supplementary power. Soyuz TM-3’s crew, Yuri Romanenko and Musa Maranov, was onboard when Kvant captured onto YMOS-1’s axial port, and failed to achieve a hard dock. The cosmonauts performed an EVA via the hub’s free ports; upon examination, a cloth sack was found jammed between the docking collars. Maranov removed it, and the modules came together with docking probe retraction. The episode once again demonstrated the importance of having astronauts on hand during orbital operations.

More modules were to be added to Mir, which was expected to be in service until the mid-1990s. The next module, expected to launch in mid-1988, was YMOS-2, now being outfitted as a materials science and Earth remote sensing laboratory instead. It would be followed in late 1988 by the TKS-derived Spektr [8], which contained equipment for demonstrating spaceborne surveillance and anti-missile defence technologies as a continuation of research aboard Salyut 7. Spektr would also carry two APAS docking ports, one axial and one lateral, to support Buran dockings in the near future.

However, increasingly apparent national economic difficulties meant that both modules were constantly delayed due to even more budget cuts and pauses. Spektr and YMOS-2 soon switched places in the queue due to the relative simplicity of the former. Thus, while in its two-module configuration, Mir would receive a consecutive string of seven visits (TM-3 inclusive), all flown using the Soyuz. In addition to the Syrian cosmonaut, three of those missions also carried Interkosmos cosmonauts from Bulgaria, Afghanistan and France (as a result of increased ESA-Soviet cooperation) respectively. With new crews often arriving before the departure of the last, Mir became host to the first permanent human presence in space. The crews also set duration records and pushed the boundaries of human habitation in space, with many Mir cosmonauts spending up to 300+ days in orbit.


After Skylab's demise, US space station proponents constantly tried and failed to get a space station approved.

From 1977 to 1982, a space station was out of the question, as the highly complex and expensive Shuttle swallowed the entirety of NASA’s budget, and no budget increases beyond the hard-fought $4 billion level were expected. However, this did not preclude concept studies, such as MSC's plans of procedurally expanding a station based around the backup Skylab or Shuttle ET wetlabs, concepts that all ended up stillborn.

Hope sprang anew in 1982 with the election of President Reagan. Reagan’s policy direction of going head on against Communism included demonstrations of the Free World’s technological superiority, and a space station that was bigger and better than the Soviets’ would do just that. Expressions of interest from Europe's ESA and Japan's NASDA were interpreted as a sign of solidarity with America, and tied into this purpose. However, as with all other projects, the station’s execution would come down to Congressional approval instead of ideological well-wishes.

NASA's new administrator, James Beggs, tried to amass supporters in Congress by approaching individual Congresspeople. The agency also commissioned eight aerospace companies to find purposes for the station, in mutually independent studies. The findings more often than not swivelled back to commercial applications, scientific possibilities and national prestige, perfectly in line with the Reagan Administration’s directions. However, they could not identify an overarching, convincing reason to justify the station. This fact would constantly hamper attempts to sell it to Congress, since for all intents and purposes of outsiders, the reasons only existed to justify a pointless continuation of the Skylab legacy. There was an element of truth to the accusation, as NASA still held onto the Integrated Program Plan dream of supporting manned exploration and Space Tugs with the station in a distant future. Thus, the station would remain multipurpose, making the design process and decisions extremely multipronged, which produced high cost estimates that only deterred supporters.

The Space Station Task Group was formed in early 1983, and one of its first tasks was to 'sketch out' a design that met the variety of needs. The resulting reference concept was the “Power Tower” station, named for the solar arrays and radiators held at the end of a 120m truss, out of the way from visiting Shuttles. The solar panels would provide the 75kW of power baselined for the station. Modularity was emphasised, especially in the pressurised modules, to reduce costs and permit switching modules for different capabilities. The pressurised modules would be clustered akin to a pendulum on the opposite side of the truss; the station could thus be gravity gradient stabilised, as the heavier pressurised section is tugged on more strongly by Earth, and thus naturally tended to point towards it.

In the interim, Memorandums of Understanding were signed with ESA, Japan’s NASDA, and the Canadian Space Agency (CSA). In exchange for incorporating and using their modules and parts on the station, these partners would shoulder part of the station's expected $16 billion construction cost, and 25% of the operating costs.

“Power Tower” was soon decided against due to the potential for microgravity experiments to be disrupted by its gravity gradient-stabilisation. “Dual Keel” concepts took their place in March 1986. These moved the pressurised modules in line with a horizontal truss, which in turn held the solar panels on its ends. On either side of the module cluster, the truss branched into bracket-shaped structures, to provide ample room for applications like servicing Mars transfer vehicles.

But in October, news of Mir's launch significantly splintered space station studies. [9] Concepts of large modules to match and exceed the Soviets' YMOS in size and mass gained serious traction. These modules would be launched aboard Shuttle-derived heavy lifters, to build stations of equivalent capacity within a few launches. However, the large module concepts barely matched the country's commercial needs, and thus a majority of support remained with 'Dual Keel' and similar modular stations.

In hopes of galvanising support for the station, Reagan named the station Freedom shortly thereafter, permanently assigning a patriotic component to its continuation. But giving a name did very little to change Congress' view of the station; it only served to alienate the more practical-minded congresspeople, and did nothing to consolidate the “directionless” proposals. Of Freedom's first budget request, Congress approved $902 million out of $970 million, after vigorous debate increased it from $200 million. Of the FY $13.3 billion 1990 budget for NASA, only $2 billion was earmarked for Freedom, barely enough for the spike in design work and hardware construction to get underway for the first module to be launched in 1993.

The station would only be given a clear, singular purpose after it was viewed as necessary to the Shuttle’s normal operations, a paradigm shift that perhaps only an accident could bring.

Author’s notes:
[1] ITTL, OV-099 did not suffer from the SSME hydrogen leaks that delayed OTL OV-099 to April 1983.
[2] Possible places of weight loss include the wing spars (as OTL), vertical stabiliser wing boxes (OTL, these parts sustained the worst thermal and mechanical stresses on other twin-tailed spaceplanes such as Hermes, and were thus likely to be significantly over-designed for ITL Shuttle).
[3] These cost estimates were done using data from the 1994 Zero Base Cost Study, and some S-1C manufacturing cost projections. It was done in an embarrassingly crude manner: I took per flight recurring costs by subtracting the 10 flight case from the 1 flight case and dividing, then added those back to the 1 flight fixed cost as a linear increase by flight rate. The results in 1994/5 dollars were converted to 1986 for these numbers here.
[4] Yes, all of these were things NASA did pre-Challenger in OTL to speed up turnarounds, albeit slightly adapted here for the different design ITL.
[5] The offer to fly a Chinese astronaut was a real thing OTL that never went anywhere after Challenger.
[6] Will be talked about in Chapter 6.
[7] Since the ITL core wasn’t (able to be) rushed to meet the 27th Communist Party Congress in February as the OTL one was, they were able to use the Soyuz-TM for the first mission. T-15 still flies ITL, albeit as a Salyut-7 only mission.
[8] ITL Kvant’s design is very similar to OTL Kvant-2. ITL Spektr’s design is a combination of OTL Spektr and Kristall; ITL Spektr has OTL Spektr’s equipment and purpose, but with OTL Kristall’s docking ports.
[9] OTL, single-module Freedoms were considered too, but neither this early nor strongly.

Illustrations of the 7SL-YMOS launch configuration and Mir as planned:

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I had a look at your mission log and you didn’t enter a landing date for one mission but the next one was three days long. What’s going on there?
I'm surprised that a "big module" space station got dismissed so quickly, with a Saturn derived booster the development cost is much lower than OTL STS-derived heavy boosters and by going for a "big module" station your overall cost is much lower as you have a higher fraction of usable space and don't have lots of expensive docking ports and inter module links.
I had a look at your mission log and you didn’t enter a landing date for one mission but the next one was three days long. What’s going on there?

One of them is still up there and what happened to it scared the other one down! Coming next summer as a Hollywood blockbuster! (Or "B" movie, it's a toss up at this point :) )

with a Saturn derived booster the development cost is much lower than OTL STS-derived heavy boosters
Would it really be? IRL most one-off large payloads like say those monolithic Alpha proposal used purpose-built side-loaded SDLV like that


But TTL’s STS has the two ET specifically arranged on both sides of the fuselage, restricting the diameter (or at least, one axis) of the SDLV’s bay without modifying the ETs, they’d have to be put somewhere else or put inline of the engine block.

While a proper, SLS style SDLV may eventually be easier once NASA gets enough funding for a completely new upper stage, a single use, purpose built SDLV actually seems harder to do.
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Would it really be? IRL most one-off large payloads like say those monolithic Alpha proposal used purpose-built side-loaded SDLV like that

View attachment 831578

But TTL’s STS has the two ET specifically arranged on both sides of the fuselage, restricting the diameter (or at least, one axis) of the SDLV’s bay without modifying the ETs, they’d have to be put somewhere else or put inline of the engine block.

While a proper, SLS style SDLV may eventually be easier once NASA gets enough funding for a completely new upper stage, a single use, purpose built SDLV actually seems harder to do.

Suspect that they'd look at is as a "Saturn Derived Launch Vehicle" as I noted above :) Cluster the ET's over a thrust structure or some such maybe? Then mount it on the Booster in place of a Shuttle?

Would it really be? IRL most one-off large payloads like say those monolithic Alpha proposal used purpose-built side-loaded SDLV like that

View attachment 831578

But TTL’s STS has the two ET specifically arranged on both sides of the fuselage, restricting the diameter (or at least, one axis) of the SDLV’s bay without modifying the ETs, they’d have to be put somewhere else or put inline of the engine block.

While a proper, SLS style SDLV may eventually be easier once NASA gets enough funding for a completely new upper stage, a single use, purpose built SDLV actually seems harder to do.

Suspect that they'd look at is as a "Saturn Derived Launch Vehicle" as I noted above :) Cluster the ET's over a thrust structure or some such maybe? Then mount it on the Booster in place of a Shuttle?


As @RanulfC says you have a perfectly good in line first stage in use. So either recreate the S-II stage from the Saturn V or build a "Big Centaur"/ET cluster/alternative new 2nd stage and bingo you have a heavy lift semi-reusable TSTO and the only development cost is that second stage and maybe some launch tower plumbing if you can't get it to use the STS launch tower unmodified. It's not going to have the payload of the Saturn V or be as efficient as a purpose designed clean sheet rocket but it'll be cheap to develop and with any system it's cost will be derived from its flight rate.
The added advantage of all this is you're perfectly set up for a Skylab style semi wet/semi dry lab station with your dry lab fixed onto your second stage which provides wet lab expansion space. Meaning you can potentially get a massive volume with only one launch.
The looks towards the real world and real people's thoughts, like what I did with Proxima, are the things that really sell these timelines. Great stuff today! It is very interesting to see how problems can creep into a system, and how we can work to solve them - those paths of divergence are what make timelines like this super interesting. Mir's dawn is also certainly a shock for the Americans, and you'd think would motivate us more.
The station would only be given a clear, singular purpose after it was viewed as necessary to the Shuttle’s normal operations, a paradigm shift that perhaps only an accident could bring.
As with a lot of shuttle timelines, the threat of an accident looms large. I am curious, nervous, and excited to see what you do here. Really really excellent work, as always.

Act 2 Chapter 5: 80s planetary science and space astronomy; Shuttle-Centaur

Chapter 5: “The Disunited State of Planetary Exploration”

Delta #144, a 2000-series Thor, breathes condensation into the wind at LC-17. Its slim core stage holds a measly hundred tons of kerosene-oxygen fuel; the rocket had no other cryogenic fluids, with all stages besides the first using storable or solid propellant. Yet, this combination’s cromulent efficiency sufficed for ISEE-3 (Explorer 59), the third vehicle of the NASA-ESA International Sun-Earth Explorer project.

“5,4,3,2,1.” With the solid strapon boosters igniting, smoke instantaneously blasted out of the flame trench.

“Zero, and liftoff the Delta with ISEE-3, on a mission to explore the boundary between Earth and the Sun.”

The Delta leapt off into the sky, perfectly injecting the payload into a trajectory bound for the L1 libration point; a region of empty space where the Sun, Earth and Moon’s gravitational forces are balanced. The probe would complete its primary mission and more; renamed the International Cometary Explorer (ICE), it would attempt to enter the plasma tail of comet Giacobini-Zinner. The extended mission would also pioneer the use of three-body orbital dynamics, used by ICE to obtain lunar gravity assists and get to the comet with minimal propulsion.

Delta #144’s successful launch continued counting down the expendable launcher’s numbered days. And nearly a full decade would pass before the United States launched another dedicated deep space probe, ending the streak of robotic explorers that defined the 1970s; much of that could be attributed to the mismatch of NASA’s old approach to grand unmanned missions with a new era of shoestring budgets.


The Centaur upper stage survived the end of its expendable progenitors, through a combination of great benefits for its costs, and onerous political lobbying.

With the idea of a reusable Space Tug dying out, an additional upper stage carried in the payload bay was necessary to preserve geostationary and interplanetary launch abilities. The former was particularly critical, as it was also required for national security payloads. Planetary scientists would simultaneously lobby for the latter; budget cuts have forced NASA to divert all funding to the Shuttle, leaving precious little for the grand Mariners, Vikings and Explorers that have defined the 1970s. It was a situation that remained just as dire under the Reagan administration.

In 1973, Convair (later General Dynamics) spent eight months performing the 'Reusable Centaur Study', which analysed twelve technical aspects required to make the Centaur-D, then used on Atlas and Titan, compatible with the Shuttle. It concluded that such a program was “extremely low risk” and that “no technology breakthroughs” would be required.

But Centaur was not the only way to go. Three other proposals were also on the table: a modified Titan Transtage, Boeing’s solid-propellant Inertial Upper Stage (IUS), and the Interim Orbital Transfer Vehicle (IOTV) that also ran on hydrolox. While the IUS could satisfy the DoD’s existing needs, it placed hard limits on future capabilities; the Transtage was no better, and had the additional problem of toxic hypergolic propellants. For more demanding military and science missions, the Centaur or IOTV were the ways to go. The IOTV was completely new, and thus introduced development risks; thus, in a cash-strapped environment, the Centaur was practically the default winner.

However, proponents of the IUS mounted a campaign to discredit Centaur, citing the operational risks of cryogenic propellants in the payload bay (especially during an abort), and deriding its eggshell-thin balloon tanks. They also argued that putting more solid-fuelled stages on IUS permitted it to do some of the things Centaur promised. The OMB was also initially on the IUS’ side, for they believed that Centaur would be too costly.

However, Europe’s plan to evolve Ariane rockets to eventually lift more than 3t to GEO changed their mind; without Centaur, the Shuttle could not capture this market. The planetary science community would also provide a crucial last straw to tip the scale in Centaur’s favour. Using the less capable IUS for missions such as the Jupiter Orbiter Probe (JOP, later Galileo) would mean spending years in deep space for gravitational slingshots, greatly shortening operational life around the destination and increasing the risk of failure. Impulse from liquid propellant rockets like Centaur could also be controlled, permitting more precise and optimal injections for both probes and military satellites alike. With congressional support for Centaur, the OMB reluctantly permitted NASA to go ahead with the stage, under the pretext that it saved $50 million more by abandoning an American spacecraft in the International Solar Polar Mission (ISPM, later Ulysses). NASA did just that, and the ISPM became an ESA single-vehicle project with some NASA instruments, with a substantial loss of scientific return.

Responsibility for realising Shuttle-Centaur went to the Lewis Space Center in Ohio, due to its role in initially developing the stage and later converting it for the Titan 3E. They would work in conjunction with General Dynamics, who would handle the practicalities of their ideas. This project rejuvenated the nearly-closed Center with new funding and activity, necessitating young talent in the form of 190 newly graduated engineers; many of them were inspired to work in the space program due to the Apollo landings a decade prior.

To efficiently use valuable cargo volume, the Centaur’s hydrogen tank would be fattened and shortened to make full use of the payload bay diameter. Two versions will also be developed: the shorter Centaur-G (at the USAF’s behest) for longer but lighter payloads, and the longer G-Prime, for shorter payloads that need maximum impulse.

The Lewis engineers’ most controversial change would reverse General Dynamics’ statement that Shuttle-Centaur needed "no technology breakthroughs": the stage would launch 90% fuelled, and make up for the remainder by drinking from ET residuals after SECO. This would necessitate development and demonstration of rapid on-orbit cryogenic propellant transfer. Fuel transfer is particularly tricky in microgravity, as the distribution of liquid propellants and ullage gases would be uneven in those situations; any pump would have to contend with cavitation, unless a constant acceleration is applied in the direction of the tank outlet. But if this technology was developed for Shuttle-Centaur, wasted mass (which on the final stage, cut pound for pound into the payload capacity) could be salvaged for a better purpose. It was also deemed easier than dealing with the complicated fluid dynamics of transferring fuel against the pressure gradients main engine operation created.

The budgetary and technological risks were further justified by extending it as a solution to other longtime fears about the stage. For example, transfer technologies would reduce the need to run the Shuttle at its bleeding edge; the Shuttle only had a 25t payload capacity, while a fully fuelled Centaur G-Prime without payload would take up 22 of those. Decreasing the payload mass also reduced the mass that needed to be cut from the Standard Weight Tank (SWT) ETs, to produce the Light Weight Tank (LWT) that Centaur-carrying missions required. It also increased the thrust-to-weight margins for a single engine failure, which was once a contingency that required thrust levels above the J-2S engines’ design level. With this change in requirements, the Rocketdyne engineers would be free to increase specific impulse without worrying about increasing thrust. The fuel lines through which Centaur drew its fuel from the Shuttle could also be used to load it on the pad, reducing the need for bespoke connections through the payload bay doors. Fuel venting during an abort was also rendered unnecessary, as the Centaur’s propellants could be fed into the ETs, increasing the Shuttle’s abort propulsive capabilities. The then-under development Shuttle could be designed to permit such modifications.

To bring cryogen transfer technology to fruition, a demonstrator would be carried on a Shuttle flight. General Dynamics figured out a way to create such a payload cheaply (at a then-unheard of $7 million), by maximising use of existing hardware and eliminating free-flight capabilities. Further sweetening the deal, the company also proposed using its own funds to shoulder part of the development cost. Said payload would come to be known as the Cryogenic Fluid Management Flight Experiment (CFMFE) [1], and would attempt to transfer small amounts of LH2 and LOX between pairs of representative tanks made from Centaur-D end caps. The whole assembly could be contained within a single Spacelab pallet.

At this onslaught of conceptual changes, the OMB was even more convinced to classify the Centaur as a “discretionary expense”. While it recognized the stage’s importance, Shuttle-Centaur and all related developments would be denied funding until 1983. This would also mean a first flight in 1987, too late for Galileo. But with some cases made by members of Congress such as Harrison Schmitt (of Apollo 17 fame) and representative Bill Lowery of San Diego (where Convair was headquartered), $140 million was allocated for the program via the Emergency Appropriations Act, permitting development to start in 1982 and the first flights to take place in 1986.

In the meantime, an alternative stage was required to tide over payloads projected to fly in 1979-1986, and lest the Centaur take too long to develop or fail entirely. Boeing’s IUS was selected, and renamed the Interim Upper Stage to reflect its hopefully transient role. It would readily fly on the last Titan 3 rockets starting in 1982, a point Boeing and the stage’s stakeholders often brought up in times of Centaur difficulties.

Shuttle-Centaur would be delegated to both the Lewis and Johnson space centres, and developed in a very short timeframe. The Lewis engineers wanted to classify the stage as a ‘payload’ instead of an ‘element’; this distinction mattered, as ‘elements’ usually required more scrutiny from the JSC’s human spaceflight considerations, reducing the amount of autonomy Lewis had and increasing the potential bureaucratic mess. However, they were overruled on the grounds of Centaur being connected to Shuttle’s propellant system, making it an ‘element’. [2]

JSC staff then proceeded to pull Lewis’ engineering assumptions apart. This required additional changes that often further complicated the Centaur. While the directors of both Centres were able to remain mutually respectful of one another, this did not extend to the staff; Lewis engineers felt that JSC did not understand Centaur well enough and was hard to please, while JSC engineers thought that Lewis was unreceptive to crew safety and tardy with changes. JSC’s perceived dominance and the time wasted with writing inter-center memos also did not help the sentiments. Development work proceeded, but slowly, with redesigns lurking around the corner with each problem thought to be solved, and ever increasing levels of mutual ire.

In late 1984, JSC director and former flight director, Glynn Lunney, proposed a 1-week cooperative discussion to create a comprehensive set of safety ground rules. What emerged afterwards was the ‘Centaur flight decisions philosophy’, which dictated conditions in which the Centaur should be immediately jettisoned from the Shuttle to prevent Loss of Crew and Vehicle (LOCV), as well as the conditions a jettisoning procedure would have to meet. This concerted effort eliminated the feuds over safety for a very long while, although the mellower disagreements over implementation would remain. The safety protocols would only be reasonably finalised shortly before the first Centaur G-Prime was delivered.

Despite all this, morale within each Centre remained stellar. This was helped in no small part by the variety of team-building strategies implemented by management, such as creating a calendar that counted down to the first launch and adopting a logo for the program.

Meanwhile, both the LWT and CFMFE were demonstrated on separate Shuttle missions. The LWT, which was half a ton lighter per tank and had LH2 syphon outlets placed lower in the tank, debuted on STS-7 and soon became standard issue. The CFMFE flew on STS-51-B in April 1985 on Discovery, alongside two commercial satellites; upon reaching orbit, the experiments immediately began due to the fluids’ volatility. One of the Payload Specialists on board, a General Dynamics employee, put the experiment through its paces from the “Igloo'' module. Fibre optic cameras recorded images inside the tanks on film for analysis. Before each fuel transfer began, commander Karol Bobko would begin firing Discovery’s RCS thrusters to settle the fuel.

Four transfers were made for each fuel component; first slowly to prove that the method worked, then a much faster one to demonstrate the rates needed to top up a Centaur in the short window before ET separation. The same was repeated while ullage was applied using the weaker vernier RCS thrusters. The transfer proved successful in both cases; after all the planned tests were completed, the fuels were separately vented into space, safing the experiment for the rest of the mission. Discovery would land at the Cape 7 days after launch; once again, the concrete runway ripped the tires apart. Such tire issues would not be solved until early 1990.

At this point, total Shuttle-Centaur expenditure exceeded the highest estimates in the 1973 study; technical challenges and the myriad of requirements imposed midway nearly doubled the development costs. The stage was only politically cleared for flight status due to its necessity, and its advanced state of development when things did begin getting out of hand. Shuttle-Centaur was thus often used as a textbook example of “requirement creep” in management courses; it was by no means the only project that suffered from it in 1980s NASA.


In May 1985, crews for the first two missions utilising Centaur were named: Commander Frederick Hauck, Pilot Roy Bridges, Mission Specialist David Hilmers and Mission Specialist John Lounge would fly on Independence for STS-61-E, launching Ulysses. Commander David Walker, Pilot Ronald Grabe, Mission Specialist Norman Thagard and Mission Specialist James van Hoften would crew Pathfinder for STS-61-F, launching Galileo. All eight men were selected for their experience and demonstrated immunity to space sickness, as the Centaurs would have to be dispatched on the first flight day to minimise LH2 boiloff.

Both payloads would also have to catch the 1986 Jupiter launch window. The pressure was thus on to launch the missions a mere five days apart, within their respective 1-hour windows. While the inauguration of LC-39B with STS-51-J made this possible, there were serious doubts that it could be safely achieved, particularly among the astronauts. Among other things, they wondered if the stage was safe; some began pejoratively referring to the stage as the “Death Star”. Thus, the head of the Astronaut Office, John Young, along with Fred Hauck, took the issue to the JSC Configuration Control Board. To their surprise, the Board ruled Shuttle-Centaur’s risks as acceptable. Privately, Hauck asked if any members of his crew wanted to reconsider flying; none of them objected to it.

Ironically, public concern and opposition mostly lay with the nuclear heat sources used in both probes’ Radioisotope Thermoelectric Generators (RTGs), necessitated by the probes’ distance from the Sun. The April 1986 Chernobyl disaster increased worries that contamination would spew from a botched launch or payload deployment. NASA responded that the safety standards mandated for the crewed Shuttle made them the safest planetary launches to date; even if the worst occurred, the nuclear fuel pellets were contained in effectively indestructible casks.

In late March, Discovery flew the last mission before the double launch; both Centaur stages were already delivered via Super Guppy, having received last-minute fixes to problems encountered during testing. The Cape would remain serene as Shuttle-Centaur underwent its last integrated tests, using Pathfinder and the first G-Prime as pathfinders. These tests sorted out an exhaustive myriad of issues that almost overwhelmed the schedule. But by April, two Shuttles were simultaneously prepared for the first time; the Centaurs were integrated with their payloads, then mounted into Independence and Pathfinder. Thus far, OV-099 and OV-104 were the only orbiters that have been made Centaur-capable.

On 15th May 1986, Independence launched atop the brand-new Booster 608, after experiencing an unplanned hold due to erroneous fuel cell readings; Ulysses and the first Centaur G-Prime rattled in its cargo bay, kept taut by internal pressure alone. The vehicle adjusted admirably to the large, sloshing weight of fuel, and STS-61-E was inserted into a position to achieve a 300 km orbit at 28° inclination; this low altitude was selected to compensate for the Shuttle’s slim margins with the heavy Centaur.

The crew immediately sprung to action upon SECO; switches were thrown on a dedicated Centaur Control Panel, prompting Independence to automatically apply ullage, and pump residual propellants from the ETs into the Centaur. While fuel flowed, no frivolous communication was made between the spacecraft and Mission Control. Hilmers later remarked that he was instinctively listening for noises hinting that the Centaur was leaking or ripping apart, despite knowing that there was nothing he could do even if it was.

30 seconds later, barber poles rolled grey, confirming that valves on both ends were shut. The empty ETs were then separated, tumbling away to a fiery end. The OMS-2 burn was negligibly shortened by the long ullage burn, and the crew was safely in orbit; OMS-1 was omitted as 61-E flew the more efficient direct ascent trajectory pioneered by STS-41B. A new race against the clock began as hydrogen was slowly boiling off, and vented via a port on the Shuttle’s aft fuselage. Every second wasted would reduce the margins for Ulysses, until two days later, when there wouldn't be enough fuel left to complete the injection.

Procedures for deploying a Centaur somewhat resembled those for the IUS, except with more things to watch over. The stage was raised 70° from horizontal, with the comically undersized Ulysses perched at its end. One by one, the systems were isolated from the orbiter’s, and handed off to onboard equivalents. Two hours after launch, the Super*Zip separation system actuated, and the first Centaur-G Prime was free of its Shuttle ride. Independence pulled away with a few pulses of its thrusters, before the Centaur's RCS system was allowed to fire and stabilise the stage.

Various cameras began imaging the departure, ranging from 16mm film engineering recorders to 70mm film handheld shots of pre-planned angles. An IMAX camera would have been carried, but NASA objected to avoid adding to an already intensive set of tasks. After the visual inspections were complete, the Shuttle performed a separation manoeuvre to distance itself once and for all.

Half an orbit later, with the Shuttle a safe distance away, the Centaur's RL-10 engines came to life. The stage would burn near depletion, increasing Ulysses' relative velocity to Jupiter. Eight minutes later, all the toil to bring 20t of hydrolox fuel into orbit paid off; Centaur shut down on schedule, with Ulysses' heliocentric orbit stretching beyond Uranus. This excess velocity maximised the gravity assist from Jupiter, used to throw the probe out of the ecliptic plane. The Centaur's last job was to spin-stabilise Ulysses, before launcher and payload parted for good. The Centaur then made an evasive manoeuvre, and drifted until its power ran out.

Ulysses' particle and wave sensors were tested during the outbound journey, and gathered some additional information about Jupiter during the gravity assist. It emerged from the planet's sphere of influence into a heliocentric orbit inclined 80.2° degrees more than what it started with. This trajectory would take it over the Sun's poles thrice in its operational lifespan, reaching perihelion in 1992, 1998 and 2004. The extended mission also saw it fly past several comets, before its last communication system failed in late 2004; by then, Ulysses had operated for 17 years, four times its design life.

After launching Ulysses, STS-61-E stayed in orbit for a total of four days, to complete the other experiments carried aboard. While Independence rolled to a stop at the KSC in the dead of night, Pathfinder’s last countdown demonstration before STS-61-F was taking place.

Launch proceeded exactly on schedule on 22 May 1986; Pathfinder was placed into a similar orbit as Independence had been. The fuel transfer was again successful, although tank pressures did momentarily creep above that of Ulysses’s Centaur. However, the reassurance of precedent didn’t make Mission Specialists Thagard and van Hoften any less cautious. Galileo was pivoted into launch position, and the process of turning on the Centaur’s systems before isolating it from the Shuttle began.

Progress was suddenly halted before switching to onboard power, for the Centaur’s lone 150Ah silver-zinc battery had turned into a potential bomb. [3] The controller responsible noticed temperature and voltage fluctuations; after investigation, the pattern resembled what was noted on Apollo 13, shortly before one of the LM’s batteries blew its pressure relief disc. That incident was caused by hydrogen gas buildup, as the potassium hydroxide electrolyte was electrolyzed over days of operation. Increasing the output load would risk arcing, which would detonate the battery. While the explosion was unlikely to inflict further damage, losing power before the burn was completed would doom Galileo.

Mission planners looked to the Lewis Center’s "Centaur flight decisions philosophy", which was barely finalised before STS-51-E. In it, ditching the stage was a consideration, if it or the payload was "at risk of contaminating the payload bay". While the rule was written with thruster hydrazine in mind, it was the only one that applied; the crew certainly couldn't take a vented Centaur and Galileo back home, lest the battery explode while the bay doors were closed, with unknown consequences. But if the combination was dumped in LEO, the RTGs would pose a safety risk if it decayed from orbit. The probe would also be lost, along with the prestige and trust needed to fund any future planetary mission.


Pathfinder completed another orbit while ground controllers weighed the options. Slowly, it was understood that the crux of the problem was a spontaneous explosion. The rule book was redundant; following it would doom the probe, while ignoring it would give it a fighting chance, likely at no risk to the crew. Galileo’s RTGs would instead be used to power the Centaur, by using an umbilical that usually routed power in the opposite direction; the defective battery would remain isolated. This ensured that the combination would remain powered even if the battery blew up and vented its electrolytes harmlessly to space.

The moment of truth came, and the amount of current drawn from the battery grew while the orbiter supply decreased. With things appearing to be stable, the Super*Zip separation system released Galileo and the second Centaur G-Prime from Pathfinder. The orbiter pulled away with a prolonged RCS pulse, to achieve proper separation in less time. Galileo’s parents throughout NASA and the scientific community agonisingly waited through the next two hours; the fact that it was the agency’s first interplanetary mission in a decade meant that everyone’s instruments were riding on board, and that answers for questions generated over ten years of inquiry hinged upon it.

Due to the boiloff from three extra orbits, the Centaur finished its burn with less hydrogen to spare. After that, Galileo and Centaur went their separate ways. Controllers experimented with the spent Centaur’s battery by activating it; the battery ran down normally, without so much as a leak.

As for Galileo, it went into full operating order, spinning up its spun instrument section and unfurling its high gain antenna. The spacecraft would reach Jupiter in mid-1988; Galileo dispatched an atmospheric probe to study the giant planet's insides, before firing the previously occluded engine to enter a Jovian orbit. For the next 11 years, it would fly by all four Galilean moons, using gravitational slingshots from each flyby to time the next. The wealth of data from humanity's first outer planet orbiter ended a drought of poring over old Pioneer and Voyager data. In 1994, Galileo gleaned a host of unique data from its front-row position when Comet Levy-Shoemaker 9 collided with Jupiter. RTG power and propellant gradually ran low over the years, and the spacecraft was intentionally disposed of into Jupiter, to prevent forward contamination of the potentially habitable moons.

The successes of both Shuttle-Centaur missions rejuvenated public and governmental faith in NASA's planetary program. Those involved were given awards or recognition; the astronauts who flew merely acknowledged that they did their assigned job. Newspapers were practically saturated with space successes throughout 1986; first Teacher in Space, then Voyager 2's Uranus flyby, and now the successful dual Jovian-bound launches, all promising more to come in future years. This wave of science spectaculars meshed with a rise in science communication; with the likes of Carl Sagan and Bill Nye entering household TV screens, the net effect was that science appeared to be less and less of a national security puppet, and more as an hope for the future capable of dispelling the old ills of ignorance.

However, for US planetary scientists whose specialties aren’t solar or Jovian science, the 1980s were filled with missed opportunities. In particular, cometary scientists looked on with envy as an international fleet of probes intercepted Halley’s Comet, making its once-in-75 years perihelion pass in 1986. The Soviets launched the Vegas, Venera-derived vehicles that also deployed Venus landers during their gravity assist flybys; the Europeans had Giotto, and the Japanese launched twin microsatellites named Suisei and Sakigake. All were wildly successful, flying within close range of the bristling dusty snowball. Without the ability to fund dedicated missions of opportunity, the US effort had to settle with remote sensing experiments launched and recovered aboard two Shuttle missions; the SPARTAN-203 UV spectrometer on 51-J, and the ASTRO-1 infrared telescope on 61-C.

The contributing factors to this lacklustre national contribution have been identified long ago, and didn’t exactly go unaddressed. In the early 1980s, a variety of programs and methods sprung up as cost-saving attempts, as growing Shuttle development costs swallowed up the rest of NASA's budget. The most successful of the bunch were the Planetary Observer and Mariner Mark II programs, which supplemented the expensive flagship missions. These programs hoped to make more planetary science missions possible again, by limiting the cost of individual missions. The Observers were inner solar system explorers, supposed to stay within a $500-700 million price range, and be constructed from the abundance of Earth-orbiting satellite hardware. The Mariner Mark IIs followed a similar philosophy of using common components as much as possible. Despite this, they still came too late to rectify the dearth of US interplanetary probes between the late 1970s and early 1980s.

The mid-1980s saw three interplanetary missions under these programs approved for the 1990s. The Mariner Mark IIs were the Venus Radar Mapper (VRM) and Saturn Orbiter/Titan Probe, both based on the same dodecagonal bus. The lone Observer was the Mars Global Climate Observer (MGCO), although it would end up arguably being its own thing as JPL silently dropped the philosophies behind Planetary Observer within six months of its approval.

In practice, both programs were still too similar to flagship missions to realise the advertised cost savings.

For the time being, what the US space program had no shortage of were Earth-orbiting science platforms like the Halley payloads, either free-flying or Shuttle-bound. While this was mainly due to their relative ease and cheapness, the Shuttle’s abilities were also a major factor: it was uniquely able to perform on-orbit servicing, permitting longer uncrewed missions with more complicated payloads such as the Solar Maximum probe. Servicing could also give failed missions, such as the assortment of commercial satellites betrayed by their final stages, new leases of life. Such servicing missions were expected to begin in 1987.

But few expected for the latter capability to be necessary for NASA’s Great Observatories to succeed. This name was retroactively given to four space telescopes, each specialising in different sections of the electromagnetic spectrum, all launched into a place free from atmospheric occlusion and disturbance; the first of the series would turn out to be short-sighted.


Theorised and championed by astrophysicists such as Lyman Spitzer and Nancy Grace Roman, the concept of a space observatory was proven by less ambitious projects in the 1960s, such as NASA's Orbiting Solar Observatory (OSO) and Orbiting Astronomical Observatory (OAO). While these programs experienced their own share of failures and tragedies, their successes illustrated the potential role of space-based observations in astronomy.

In 1968, the Large Space Telescope (LST) was proposed. A reasonable outgrowth of ground-based observatories, it would specialise in the visible light spectrum with a 3m-diameter main mirror. After NASA's human spaceflight efforts were consolidated under Shuttle, it was decided to delay the launch date from 1979 to sometime in the 80s, and design the LST to take advantage of the Shuttle's capabilities instead.

Then the Shuttle budget overruns began. The telescope program originally had very little support in Congress, and was asked to downsize. This meant eschewing sensing capabilities and possibly a smaller aperture. While the rest of NASA's planetary science program either succumbed to crippling compromise or cancellation, Hubble eventually managed to mitigate both through an extremely risky gambit. Recognizing the importance of the project, NASA's Associate Administrator for Space Science, Noel Hinners, gave it a budget allocation of $0. This was meant to draw attention to the dire budget of space science projects, and galvanise the telescope's supporters into fighting for full funding. Thankfully, the move provoked more or less the intended reaction: astronomers and space science groups organised massive letter-writing campaigns and talks with congresspeople, and Congress eventually relented to providing half of the requested budget. [4]

However, the reduced budget threw a smaller 'proof-of-concept' telescope out of the window. ESA support was also needed to get through the crunch; in exchange for Europe providing the solar panels, optical instruments and manpower for the LST’s construction, European astronomers were guaranteed at least 15% of the observation time. To further save costs, the telescope would use some parts from the KH-11 spy satellite; while a classified fact, this was supported by the main mirror diameter being inexplicably reduced to 2.4m, and sightings of the telescope being transported in similar containers to the KH-11’s.

The MSFC, which was placed in charge of the LST, subcontracted the optics to two companies for redundancy. The telescope was a Cassegrain reflector, consisting of a main mirror concentrating light onto a smaller secondary mirror suspended in the line of sight, which then reflected the image into collectors through a hole in the primary mirror. The LST would use hyperbolic mirrors for their good wide-field abilities, with the caveat of being incredibly hard to fabricate and test; they would have to be ground to nanometric precision for the LST to deliver its promised clarity. To achieve this, the primary contractor, Perkin-Elmer, would use cutting-edge computer controlled polishing machines. The backup contractor, Kodak, would use more traditional methods in case Perkin-Elmer ran into any issues.

The LST’s launch was scheduled for 1983; this would soon prove impossible due to a combination of technical difficulties and budget overruns, particularly at Perkin-Elmer. Their schedules slipped at a rate of one month per quarter, sometimes reaching one day of delays for one day of work. While Perkin-Elmer got most of the flak, other teams were also trying their best to catch up, sometimes with the time the mirror delays bought them. The launch date was repeatedly postponed, first to April 1985, then to a vague late 1986.

The mirror was eventually completed in 1981, and as the rest of the telescope came together, so did its publicity campaign. The LST’s ability to deliver true-colour images of stellar phenomena served as a public relations boon, and it was thus touted as NASA’s premier science mission for the 1990s and beyond. The Space Telescope Science Institute (STScI), established to manage the telescope’s science and allocate observation time, focused on making recorded images and data publicly accessible as they come in. The STScI also made spare observation time slots available to literally anyone who could present a good enough case for their imaging target. It was hoped that this publicity would pave the way (both practically and politically) for other less visible telescope projects, also proposed in the late 1970s: the Compton Gamma-Ray Observatory, the AXAF X-ray Observatory, and the STIRF infrared telescope.

In 1983, the LST was officially renamed the Hubble Space Telescope, after the astronomer who empirically determined the universe’s expansion rate; this was but one of the many questions Hubble’s observations could explore in-depth.

Hubble was finally delivered in mid-1986, shortly after the twin Shuttle-Centaur missions concluded. There, it was loaded into Discovery for STS-61-I, scheduled to launch on 16 August. This flight possibly had the most experienced crew assembled to date; it would be commanded by John Young, on his last flight before retirement. Things went well right up until engine chilldown on launch day, when hydrogen concentrations in the interstage increased. Inspections found leaks from a J-2S engine, which would have to be replaced. This necessitated rolling the entire vehicle back to the VAB, destacking it, then replacing the engine in the OPF. [5] 61-I could only make another attempt by mid-September, barring any more issues. In the interim, Independence and Pathfinder would fly on 61-J and K respectively. The former was a Cape-launched DoD mission, while the latter would recover the LDEF material exposure experiment launched on 41-A two years ago.

Discovery’s delay was a godsend for the Hubble team, who used the extra time to brush up their software and other barely finished work. But many others were less pleased; to Shuttle program managers, it was inconceivable that technical issues could still deliver heavy blows to the schedule, in such a mature operational system. The delay also pushed two planned flights beyond 1986, meaning that the Shuttle wouldn’t be able to hit its quota for another year running. Even more frustration came from the DoD; with the resulting mission switcheroo, and Pathfinder returning from 61-K with damage that couldn’t immediately be fixed due to spare parts shortages, none of the lighter orbiters (OV-103 and 104) were immediately available to support STS-62B, the second Vandenberg polar mission, originally slated for October 1986. As a result, 62-B was bumped into late December, to be the year’s final Shuttle mission. To the DoD, this episode further illustrated the problems of sharing a launch vehicle fleet with NASA, as they were increasingly relegated to scraps between time-critical events dictated by vehicle issues, orbital mechanics and international agreements.

Hubble retreaded its journey back to the launch pad in early October 1986, and finally lifted off on the 15th. At 615 km above Earth, Discovery launched into the highest orbit reached by an orbiter to date; this altitude was selected to give Hubble maximum orbital longevity, as it had no propulsion system. On Flight Day 2, the crew got to work extracting Hubble out of the payload bay. Bruce McCandless, Steve Hawley, and Kathryn Sullivan commanded and supervised the deployment of various appendages from the flight deck. The IMAX cameras barred from the Centaur missions were also present, recording moments for a NASA-sponsored special feature on the telescope. While a contingency spacewalk was in the books, none ever had to be conducted. By the end of nine gruelling hours, the HST was free; only its aperture shield remained closed to prevent contamination from Discovery’s RCS jets. With the main mission complete, the crew then spent the next three days tending to various experiments.

In the weeks following Discovery’s return, Hubble began sending its first images home. The Wide Field/Planetary Camera (WF/PC) was indeed delivering better images than ground-based observatories; however, there was severe spherical aberration, making it impossible to obtain the designed sharp focus. The regularity of this distortion hinted that something was wrong with the optical assembly. Thus, a JPL team was assembled to diagnose the issue. The problem was eventually traced back to Perkin-Elmer’s primary mirror, which was ground wrong using uncorroborated calibration settings. The resulting uniform 2nm difference decimated Hubble's ability to image dim and/or wide-angle targets.

Fortunately, the error in accuracy had no bearing on the mirror’s precision; by working backwards from the blurred images, the error could be precisely characterised, and thus made correctable. With Hubble being designed for orbital servicing, corrective optics could then be installed to solve the problem. The first servicing mission was thus advanced to 1988, or as soon as the workaround could be designed and built. In the meantime, astronomers would simply have to contend with the reduced capabilities; computer processing was used to salvage the blurry images, while less demanding observations would be prioritised. The telescope would also continue being a disappointment for its command and control issues. The intervening years would see valuable observation time lost to maintenance and technical difficulties, due to what was effectively work-in-progress software. Thankfully, none came close to disabling Hubble. Changing the ground-based half could only do so much to solve the control problems, so a software upgrade was also added to the first servicing mission's list of tasks.

But no amount of engineering could salvage the observatory's reputation. For all the hype generated beforehand, Hubble now represented a massive public relations liability for NASA, with politicians regretting, scientists bemoaning, and the media ridiculing it. The Government Accountability Office (GAO) even launched an investigation into the telescope program; very early drafts of the report called for better communication between management and engineering, more effective oversight of contractors, as well as realistic expectations for timelines. These words would prove prophetic long before their planned publication in December 1986; the HST's period of mediocrity would also end up lasting longer than anyone expected or wanted it to.

The critical firestorm also affected other telescope programs to some extent. While Compton and AXAF were sufficiently far along to evade major changes, the SIRTF project was deferred in the conceptual phase. The original SIRTF called for the Space Tug to push a free-flying infrared telescope to a high Earth orbit, away from the thermally polluted environment near a Shuttle. After the cryogens required to cool the telescope’s mirror were depleted, the Tug would take it back to a Shuttle, which would take it back to Earth for refurbishment. With the Space Tug increasingly unlikely to materialise, and an estimated total project cost of $2 billion (when the $1 billion Galileo was already a hard sell), Hubble’s negative publicity only added another reason to not proceed with it for subsequent fiscal years. SIRTF’s scientists and engineers would have to change their proposal to reduce cost and risk, and hope for greener budgetary pastures.

Author’s notes:
[1] I do not have designs for the CFMFE; however, it should be similar in design to things like COLD-SAT in OTL, as they have similar purposes.
[2] Centaur was classified as a ‘payload’ in OTL, which led to conflicts between Lewis and JSC as well; so I intentionally played up the irony of displeasure still existing despite the inverse happening, and tried to do it in a conceivable way.
[3] This issue was purely for drama, after I realised that Shuttle-Centaur has no redundant battery.
[4] As insane as it seems, this actually happened in OTL.
[5] The J-2S engines on Discovery would have flown 7 times at this point, assuming they were never replaced; the usual problem-free nature of these engines would have meant that they were given less attention than SSMEs were OTL, culminating in this. It’s also meant to illustrate another disadvantage of series-burn Shuttle designs that put engines inside interstages: the engines could not be replaced/repaired without destacking.
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It is always refreshing to see attention paid to probes and their story, excellent chapter as always! Galileo's anxiety ridden voyage is certainly something, and an element of drama is never far off in spaceflight OTL! Looking forward to the next one.
Act 2 Chapter 6: 80s military spaceflight; SDHLVs for SDI

Chapter 6: “May the Accelerated Mass be With You”



> Space station module launches might be demonstration flights for super heavy launch vehicle, which will launch Soviet space shuttle Buran

> Super heavy launch vehicle and its derivatives can serve all Soviet military and civil space needs for the next 30 years
Satellite imagery obtained by the Department of Defence has revealed that the Soviets are preparing a new super heavy launch vehicle. According to TASS, the super heavy launch vehicle will launch a prototype space station module. However, reports about this launch vehicle are nothing new.

The super heavy launch vehicle is part of a new series of launch vehicles the Soviet Union is developing, to cover payload capabilities ranging from 20 tons to over 100 tons.

The launch vehicle adopts a modular design to meet a variety of payload mass ranges.

The 1983 issue of Soviet Space Power has identified three variants, using a combination of satellite imagery and limited information released by the Soviets:

- Medium launch vehicle: 20 tons to LEO
- Super heavy launch vehicle 1: 100 tons to LEO
- Super heavy launch vehicle 2: 120 tons to LEO

There appears to have been no change in the list of variants. Five instances of the medium launch vehicle have been imaged since March 1985. The first 100 ton super heavy launch vehicle was sighted in early 1985, followed by its disappearance and reappearance several times. This is assumed to be due to movements of a test model, as no launches were reported. A second and third airframe were confirmed in early August this year. It is unclear whether they are also test models, or flight vehicles. [1]

In a major departure from past Soviet designs, the launch vehicles use hydrogen-oxygen fuels in their upper stages. It is unclear when the Soviet Union began developing this technology, although the time frame could be placed at the late 1970s, according to known Soviet launch vehicle development times and sightings of test stands.
However, preliminary estimates of the launch vehicles' dimensions show a remaining discrepancy between their dimensions and payload capacities.

"There are several explanations, but we tend to believe that they are either supercooling the fuels to increase their density, or they have mastered extremely low mass fraction tanks. The US has not employed either technology, at least not to the extent needed for all of the numbers to be true." the leader of the DoD-commissioned analysis group comments.

The launch vehicles and their related infrastructure appear to employ a combination of design philosophies to make it more cost effective than past Soviet launch vehicles.

- Modularity: The lower stages of the super heavy launch vehicles are made up of clusters of common boosters resembling the medium launch vehicle lower stage.
- Reusability: According to insider information, packages on the super heavy launch vehicle boosters have been identified as recovery hardware. They will allow the boosters to land softly in a horizontal position.
- Reuse of existing facilities: The launch site for the super heavy variants, Complex J, was originally developed for a completely different super heavy launch vehicle in the 1970s, the existence of which was also determined based on US satellite imagery.
- Possible use of civilian facilities for logistics: The common boosters have dimensions that are compatible with US rail facilities. The DoD thus extrapolates that they are also intended to be transported via the Soviet Union’s railway system before flight and after recovery.

It is thought that the Soviet Union has come to similar conclusions as the United States regarding launch vehicles, as the payload capacities correspond to those of the Griffin SDHLVs being considered by the USAF for national defence purposes.

“They have designed their rocket from the outset to fill every niche up to a hundred tons, while we’ll be struggling to build back the heavy-lift capabilities we gave up.” SDI Deputy of Technology Mike Griffin stated.

The 120 ton variant represents the pinnacle of Soviet launch capabilities, and is likely to see significant use if they commit to countering the SDI program using similar capabilities or countermeasures. With reference to payload masses projected for SDI, a 120t payload capacity is more than capable of placing such payloads into orbit.

Owing to the very similar payload capacities of the two super heavy lift variants, the 100t variant appears to have been developed solely for launching the Buran large space shuttle.

The 20 ton variant is likely a replacement for their currently most powerful launch vehicle, the Proton, which they have been using since the late 1960s for both military payloads and space exploration vehicles. The reasons for such a replacement are unclear, although its use as a carrier for the small space shuttle is the most accepted reason. [2]

Assessments of how much capability remains in these launch vehicles will depend on the accuracy of US intelligence assumptions, which will have to be calibrated using information the Soviet Union may reveal in the future. However, the DoD believes that growth is contradictory to the design philosophy behind the new launch vehicles. "The launch vehicles are tailored to the payloads they [the Soviets] could launch now and in the near future," General Donald J. Kutnya states.

Notably missing is a launch vehicle in the heavy lift class. However, analysts say that according to the philosophy used to create the 100 ton version from the 120 ton version, the super heavy launch vehicle could easily be further reduced to carry payloads massing between 40 and 60 tons.

The new launch vehicles also provide a secure foundation for a human space exploration program. With the small and large space shuttles, the launch vehicles could be used to reliably send crew or cargo respectively to low Earth orbit. It is also likely that the Soviets would choose to expand beyond low Earth orbit. "There is absolutely no question that the Soviets can undertake a lunar mission in the next few decades. Whatever they do, it would not be constrained by launch capability." NASA Deputy Administrator William Graham comments. The catch is whether they would be able to fund it, after creating Space Shuttle and Skylab equivalents simultaneously, the former of which has required almost all of the US space agency's resources. To this, Graham adds "there are no signs that their investment would decrease."

Discovery was the orbiter that participated least in the 1986 slew of launches from the Cape. While Independence was deploying TDRS-C during STS-61-G, OV-103 was refurbished and brought to the West coast via SCA, to fulfil one of the obligations NASA had to accept during the Shuttle’s development: fly from Vandenberg on high inclination missions for national security payloads. While low-inclination DoD missions have flown from the Cape in relative secrecy, Vandenberg coming online finally enabled polar orbit missions.

For the Shuttle program’s first polar mission, Discovery was mounted with a secret defence payload; later declassified documents would reveal an infrared tracking demonstrator named Teal Ruby, which was co-manifested with a prototype laser-based communication system.

OV-103 was stacked atop Booster 609, which had been delivered brand-new exclusively for use at Vandenberg. The entire combination was checked out in the Shuttle Assembly Building, before two locomotives slowly pulled the stack into the night. System designers prided themselves in the efficiency of Vandenberg’s setup, which consolidated payload processing and stacking in one building, and put the launch pad much closer. The entire facility had been tested using Constitution and S-1D-BTA in incrementally representative fit checks over most of 1985.

On July 1 1986, the USAF "Stars and Bars" on STS-62-A’s booster frosted over, as LOX coated the other side of the sheet metal. This was the second launch attempt; the previous one was cancelled three days ago owing to inclement weather at the booster recovery site.

Shortly after dawn, the roar of F-1A engines pummelled the rocky cliffs, and shook nearby residents from their sleep. Discovery rose skyward, with Navy Captain Robert Crippen as its commander; the rest of the crew, military officers who became one-time Mission/Payload specialists, had uniformly high security clearances. STS-62-A pitched westward over the Pacific, before making a dogleg turn for the south. Continuing to fly along the coastline, the usual launch events came and passed perfectly. Booster 609 separated, and splashed down in the tropical Pacific waters for recovery by MV Liberty Clipper, sister ship of the vessel operating from the Cape. The ETs were then exhausted, and reentered over Antarctica.

Discovery and its crew would stay in orbit for four days, covering most of the Earth with its ground track before returning to Vandenberg’s own Shuttle Landing Facility, which was an extended pre-existing runway. After the mission, OV-103 would be returned to NASA for East coast missions, while Booster 609 would stay at Vandenberg for future polar missions, being too cumbersome to move via road, and too cost-ineffective to frequently move via barge. While STS-62-A proved the feasibility of using Shuttles for polar missions, it also revealed some problems with SLC-6: acoustic damage sustained by Booster 609 proved the sound suppression system inadequate. Nearby buildings also sustained significant blast damage, casting doubt on the value of the site’s tight-knit layout.


In the US, past administrations since Eisenhower’s have all accepted Mutually Assured Destruction (MAD) as the norm. This fact was a peeve for Reagan himself and many members of his administration.

The Strategic Defence Initiative (SDI) was started in 1982, calling upon U.S. scientists “to turn their great talents now to the cause of mankind and world peace, to give us the means of rendering these nuclear weapons impotent and obsolete.” SDI would use the new tactic of Ballistic Missile Defence (BMD), which involved building capabilities to disable the enemy's missiles during a nuclear attack; ideally, this would deter the Soviets from further increasing their nuclear arsenal, and using their missiles at all. Thus, BMD would ideally result in a denuclearized peace, with the US in a strategically superior position.

BMD requires the ability to rapidly detect nuclear warheads, and coordinate a response to disable them. Detection and coordination were readily achievable; the hardest part was intercepting and destroying ICBMs flying at hypersonic velocities. A dizzying variety of ideas were thus proposed to provide an intercept capability; many of these involved space-based assets to gain the literal high ground.

The earliest ones involved directed energy weapons; lasers (or similar beams of concentrated energy) would be shot at ICBMs during their boost phase, before their multi-warhead payloads dispersed. Zenith Star, the most prominent as of 1984, consisted of a network of orbiting mirrors and a few laser generators. Using a hydrogen-fluorine reaction, the laser satellites generated powerful beams, which were reflected by the mirrors to target individual warheads.

To demonstrate related technologies and methods, ground and space-based prototypes for the most promising ideas were built. The Shuttle contributed to SDI by lifting many of these prototypes to space. Most were on dedicated DoD missions, to minimise security-related disruptions to commercial payload processing. Much less coverage was given to the Cape-based DoD missions, with NASA's Public Affairs Office only announcing them days before launch. Specific details were also sparse.

Yet, the STS' contribution to SDI was almost more extensive; it hinged upon the fact that an uprated Saturn V hid under the 100t spaceplane.

No existing US launch vehicle, expendable or reusable, could lift the 40t+ Zenith Star laser payload, which was only expected to grow even further. In 1985, the Strategic Defence Initiative Organization (SDIO), which managed SDI, asked the USAF to look into super-heavy launch vehicles. The USAF in turn contracted Martin and McDonnell Douglas to perform concept studies. Since few laser payloads are required, this SHLV would only be used once or a few times; it would thus use existing hardware as much as possible to save costs.

McDonnell Douglas reused ideas from a 1977 study, in which it was asked by NASA to cursorily examine Shuttle-derived heavy launch vehicles (SDHLVs). Martin built upon its 1983 NASA-sponsored Shuttle Derived Vehicle Study, which further examined designs that either upgraded the Shuttle, or switched the Shuttle for uncrewed cargo carriers (Shuttle-C). It also looked into Titan-derived options. The USAF studies picked up where NASA’s left off, fleshing out Shuttle-derived possibilities for both military and civilian applications.

In the end, four major lines of thinking emerged between the two companies. Shuttle-derived ideas, collectively named Griffin, included: ‘minimal modification’, where the orbiter was swapped for a wingless cylinder, propelled by an expendable thrust structure derived from the aft fuselage; ‘minimal development’, where new upper or lower stages were clustered from tanks made using 5.5m diameter ET tooling; and ‘maximum performance’, in which a new second stage similar to the S-II was developed. Finally, there were the Titan-derived options, collectively named Barbarian.


The ‘min-mod’ option was initially preferred, as by keeping the booster and ETs in the Shuttle stack’s positions, it would have had minimal impact on ground infrastructure at both the Cape and Vandenberg. However, it could only carry payloads with diameters up to 5m and weighing up to 45t; the mirrors were 7m in diameter, and the laser was already dangerously close to exceeding the payload capacity. ‘Min-mod’ soon faded from the spotlight as SDI’s ideas continued to be in flux, meaning that the heavy lifter would have to be able to accommodate a variety of plans, some which required recurring launches. NASA had also gotten aboard the Griffin program, attempting to ride on DoD funding to obtain super heavy lift capabilities it couldn’t get funds for. Increasing intelligence about the Soviet heavy lifter, later known to be named Energia, also kicked the calls for a long-term heavy lifter into high gear.

With this increase in potential uses and users, the SDHLV efforts were consolidated into the new National Heavy Launch Vehicle (NHLV) program in January 1986. [3] Accordingly, all talk of Griffin turned to the ‘max-performance’ model, which would be cheaper to operate with any substantial volume of launches in the long run. The concept also evolved to incorporate some ‘min-dev’ philosophies: the HLV variant’s 10m stage would attempt to use S-1D parts, while a smaller version (confusingly named the MLV despite having a HLV payload capacity) with a monolithic ET-derived second stage was also proposed.

The Griffin MLV was also deemed useful outside of NHLV’s context, as the DoD had been looking for alternative launch vehicles despite NASA’s opposition. The Shuttle’s poor turnaround performance had led to the Complementary Expendable Launch Vehicle (CELV) program in 1984, through which the DoD solicited bids for an alternative launch vehicle. To placate NASA, the Griffin MLV was examined for CELV, although it was eventually selected against due to its commonality to the Shuttle. 10 additional examples of Martin’s Titan 34D were instead stockpiled as a backup launch option for national security payloads. Despite this redundancy, the USAF Space Wing still ended up losing all avenues of space access for the latter half of 1986; the Titan 34D was grounded after one of the last intended launches exploded in April due to a SRB burn-through, while the NASA manifest only made orbiters available in December at the earliest.

Funding through the BMDO allowed these ‘paper rockets’ to be realised to an unprecedented degree, compared to previous SDHLVs. Analysis was done for the finer details of implementation, and full-size mockups and prototypes were built. For example, Rockwell started an experience capture program, putting together an archive of S-II manufacturing knowledge from those who had worked on the stage, both currently and formerly employed. Martin studied a refined and cheaper 10m common bulkhead by incorporating ET techniques. An economic analysis into reusing versus expending J-2S engines came to an ironic conclusion: the engines’ unit prices were inflated by their reuse on the Shuttle, which lowered the demand and thus precluded a production line approach.

In 1986, a mockup of the Griffin HLV and Zenith Star were made for a presidential address on SDI, at a Martin plant. A Michoud team cobbled together a second stage by spraying retired S-1D parts with SOFI foam, while S-1D-BTA stood in for a first stage after being rescued in a dilapidated state from the NSTL.

While the lasers made for powerful geopolitical gambling chips, and regaining heavy lift capability for more peaceful purposes was appealing, SDI would be the first human effort to put serious weaponry in space, and an attempt to completely reinvent the dynamic between the two 20th century superpowers. It was a worrying development to those opposed to the militarization of space, and the country's professed enemies.


To the Soviets, SDI was terrifying not just as a political victory, but also a strategic one; it theoretically gave the US the ability to escape retaliation after delivering a first strike. It was also seen as economic warfare; KGB Chairman and later General Secretary Yuri Andropov realised that the USSR would overexert its economy if it expanded its nuclear arsenal to overwhelm SDI's defences. Although less of a concern thanks to Energia, leaked information about the SDHLV also confirmed Soviet fears that the Shuttle had been developed for a military purpose, if not in the way the ministers expected.

Brezhnev-era foreign policy faced SDI by countering it with more technology. The USSR had been pursuing its own anti-satellite weapons since 1976; while originally aimed at disabling orbiting satellites, these efforts were mobilised in 1983 to counter the threat of SDI. The most useful weapons were Skif (lit. "Scythian"), a chemical laser capable of destroying low-orbit satellites, and Stilet (lit. "Stiletto"), which used infrared lasers to fry enemy satellite optics. The latter ran into delays and was abandoned. The former got into the demonstration mockup stage by 1986, skipping some development hurdles by using existing hardware; the laser was a 1-megawatt carbon dioxide laser derived from an airborne weapon, while the spacecraft structure and systems would use YMOS parts as much as possible.

The Skif-DM, while designated M for maket (lit. "dummy"), was practically an operational battlestation minus the laser. It would be hastily brought to fruition within a year, with construction starting from scratch in July 1985, and delivery to Baikonur in July 1986. It was further sped up to serve as the Energia’s first payload, and clear the way for the all-important YMOS-1 launch scheduled in October for the Revolution anniversary.

But in 1985, Mikhail Gorbachev rose to power, following Yuri Andropov and Konstantin Cherenko's very short periods as General Secretaries due to their health-related deaths. His rule began an era of the USSR redirecting its energies within, to tackle economic issues that Brezhnev’s rule left to ferment; thus, spending money on military and propaganda spectaculars was very far down the country’s new bucket list.

However, scaling down national defence wouldn’t be desirable if external threats remained. Through appealing to peaceful intentions, Gorbachev's administration tried to persuade and pressure the US into giving up SDI. Diplomatically, it did so through attempting to split the US from its European allies, by exploiting Western Europe's fears of SDI leading to a new arms race. These efforts were unsuccessful; Western Europe was indecisive, as their security required a politically and militarily powerful US capable of extended deterrence.

In negotiations with the US, the USSR also maintained that as long as SDI remained, there would be no space cooperation. This resulted in many proposals being declined, such as the joint manned rescue capability many aimed for since Apollo-Soyuz. But these moves were ineffective against the US, since the Reagan Administration saw relatively little value in space cooperation, compared to the immense strategic victory of pursuing SDI.

The Skif-DM mission was thus made even more incompatible with the new Soviet leader's national vision. Leading up to Skif-DM’s launch, political pressure from above forced its makers to remove or replace some functions that could hint at its true nature, which would make the USSR appear hypocritical if revealed. For example, the canisters of targets for aiming tests were left empty. Those that remained would continue to be explained away as geophysical experiments. This public explanation was a half-truth, as the Skif-DM did carry several such experiments not related to the weapon.

Throughout August, the Skif-DM was modified at Baikonur, while the first operational Energia was prepared and tested. The Skif-DM was soon stacked atop Energia-6SL, encased in shrouds similar to those to be used by the YMOS modules. The black shrouds were painted with the word Polyus (lit. "Pole"), to complete its disguise as a prototype YMOS, which was how it would be introduced to the world. With no launch window constraints, the launch was arbitrarily scheduled for 5 September 1986, to prove the Energia and clear the way for YMOS-1. This rush was solely driven by a desire to have Mir receive its first crew by the October Revolution anniversary.

After five hours of delays caused by strapon booster helium leaks, the five RD-170 engines ignited, and the first Energia ascended into the evening sky. Controllers watched the data, while preparing for anything that went wrong; in the most pessimistic case, everything only had to operate for the first 30 seconds for the rocket to steer away from the launch complex, and not destroy it with flaming debris. But by the 110th second of flight, 6SL had outlived any rocket previously launched there, and had every sign of continuing.


To maximise payload to orbit, Energia’s first stage ‘bundle’ of five common modules was split into three parallel-burning stages. Differences in burn time were created by varying the throttle of all engines in groups. By this logic, the core and one pair of boosters throttled down first, ensuring that the other pair of boosters would contribute most of the thrust and thus burn out early. Through the throttles, Energia’s flight computer constantly kept a balance between optimising velocity contribution across the stages and minimising gravity losses, with the end goal of maximising payload to orbit.

The first pair of boosters, or Stage 1.0, was separated around 2 ½ minutes after launch; the remaining pair, Stage 1.1, throttled back up to make up for the reduced thrust, before running out and dropping away as well. None of the four boosters were recovered, as the recovery system had yet to be developed. The core Stage 1.2 burnt out 3 ½ minutes after launch, and the more efficient hydrolox Stage 2 took over. The 90t Polyus successfully entered low Earth orbit, before it separated from its shrouds and what was left of the first operational Energia. It was planned to remain in space for 30 days to carry out the planned tests, before deorbiting itself.

Mere days before Polyus' launch, there were discussions in the Politburo to cancel all tests that created significant signatures, such as the release of a xenon/krypton gas mixture to test the laser's anti-recoil system. However, these concerns did not gain sufficient traction to affect the first five days of Polyus’ flight plan. Thus, Polyus conducted its first anti-recoil system test as planned, during the third mission day.

By the time the downscaling discussions made it into meetings, Polyus had been disabled during its seventh mission day. While there were initial suspicions of sabotage or American intervention, the failure was ultimately attributed to a short circuit in the YMOS-repurposed power distribution system, most likely a result of the hasty production process. Polyus would drift uncontrolled, until it decayed from orbit in 1989 and spread debris across Africa.

But for Soviet leadership, the sudden failure was a footnote compared to the other things on its plate, in the days, months and years following September 7 1986.

North American Aerospace Defence Command (NORAD) sensors detected the xenon cloud immediately. By working backwards with orbital mechanics, its position over time could be plotted. They soon realised that it converged with the suspiciously large object they started tracking several days ago, which in turn chronologically lined up with Soviet news that they launched a new “prototype space station module”. Scientists were consulted, and it was determined that it was too much gas for all foreseeable scientific purposes. However, assuming that it was released as a substitute for chemical laser reactants, the estimated volume of gas matched up with laser power levels useful as a weapon.

These findings made their way to Soviet leadership through the Moscow-Washington hotline. Through fax, assessments and printed charts of the discovery were then sent straight into Gorbachev’s hands. The Soviets were caught in an awkward position; they could either admit the severe deficiencies in its leadership structure that led to Polyus being launched despite being a relic of Brezhnev-era policy, or double down with an acknowledgement that they had been pursuing double standards all along. But by doubling down, they would have to realise the counter-SDI capabilities they bluffed about, which required immense resources they could no longer spare. Thus, they decided to continue denying its real purpose.

The ‘Polyus Incident’, as it came to be known, put the gradual warming of US-USSR relations on hold. When questioned about the gas plume in a UN Security Council meeting, the Soviet representative repeated that Polyus was a prototype station module, and that the noble gases were part of an experiment to measure their interaction with the ionosphere. However, it was noted that the representative did not mention or attack SDI, which further suggested that Polyus was somehow connected to it.

This open secret about Polyus' military nature was widely circulated in US media, which was a welcome development to SDI proponents, as it would justify SDI's necessity. By association, Mir’s October launch announcement also drew scepticism and sarcasm from the US press, with the Huntsville Times proclaiming “Another space battlestation?” On the other hand, Soviet press made no mention of Polyus other than its official explanation. Despite this, some of the overseas media frenzy made it across the border, to spark discussions about why the country was going out of its way to reciprocate another arms race with more far-fetched implications than nuclear warfare, when to many, the promised economic improvements were increasingly looking like lies.

As the UN meeting did not lead to any resolution, both countries decided to resolve the issue in the October 1986 Reykjavik talks, which were a continuation of the 1985 talks in Geneva, and touched on everything ranging from human rights to nuclear disarmament. On these more conventional fronts, the talks were a resounding success; they directly resulted in the 1987 Nuclear Forces Treaty. This banned all short and intermediate-range nuclear weapons, and put new restrictions on the number of nuclear warheads. It also banned the use of multi-warhead missiles. This was arguably the more significant outcome within the context of the Cold War.

In regards to space weaponry and strategic defence, the discussion sought to limit the scale of space weaponry by defining “valid targets”. This went through relatively easily, since both parties felt they had little to lose from. By the end of the talks, the Soviet delegation readily accepted the offer to continue such discussions, as they hoped to push for terms that would protect themselves from preemptive US anti-satellite action, which they would not be able militarily respond to; it also did not explicitly contradict their denial of Polyus' true nature.

The end result was the 1988 Anti-Satellite Warfare Treaty. This treaty made objects that could directly cause mass destruction of life and/or property anywhere the only “valid” anti-satellite targets. For debris and related damages, it also held the party that created the “valid target” responsible, followed by the party that used the anti-satellite defences if the previous line did not apply. In-space testing was allowed to continue, provided that measures were taken to ensure that all debris never reached orbit, or would decay within several days. Finally, the Soviets pushed for banning strategic defence-supported nuclear first strikes (although it was unclear how this could be enforced in practise); the US was forced to concede to avoid diplomatic suicide.

However, besides turning the conferences meant to usher a new era of trust into yet another set of mutual compromises, the Polyus Incident’s impacts also extended beyond the geopolitical sphere. For example, it was argued to have accelerated Gorbachev’s policy of glasnost, a series of reforms aimed at increasing government transparency to the public and within itself. While aimed at avoiding a repeat of the miscommunication that led to the Polyus Incident, it also increased civilian freedoms.

Militarily, the Polyus Incident also accelerated SDI’s shift away from directed energy weapons, which were falling out of favour due to foreseeable technical and theoretical difficulties. Kinetic energy-based defences such as Brilliant Pebbles instead came to the forefront, which involved shooting ICBMs with orbital velocity projectiles launched from orbiting battlestations. Nearly a thousand such battlestations were needed in these projects to cover all inclinations at all times. This was Brilliant Pebbles’ advantage over ideas like Zenith Star; Soviet anti-satellite weapons will not be able to take out that many battlestations, before being destroyed by the remaining ones.

As Brilliant Pebbles battlestations were much lighter, but required thousands of discrete launches, a fully reusable vehicle with short turnaround times was preferred. In view of lessons from the partially reusable Shuttle’s failings, SSTOs were increasingly seen as the holy grail of economical reuse. The contract for such a launcher would be awarded to McDonnell Douglas in 1987, which should have resulted in the DC-X subscale demonstrator for the vertical-takeoff-vertical-landing (VTVL) Delta Clipper SSTO by 1990. Another potential launcher for Brilliant Pebbles was the 1983 NASA AerospacePlane, also a SSTO born out of a dissatisfaction with the Shuttle’s turnaround times.



This is the transcription of the voice communications between crewmembers of the STS-61-L (ATLAS) mission.
Sources in the transcript may be identified as follows:

  • CDR - Commander (Vance DeVoe Brand)
  • PLT - Pilot (Stanley David Griggs)
  • MS1 - Mission Specialist 1 (Robert Lee Stewart)
  • MS2 - Mission Specialist 2 (Claude Nicollier)
  • MS3 - Mission Specialist 3 (Owen Kay Garriott)
  • MS4 - Mission Specialist 4 (Bryon Kurt Lichtenberg)
  • PS1 - Payload Specialist 1 (Michael Logan Lampton)
  • PS2 - Payload Specialist 2 (Robert Everett Stevenson)
  • UN - Unidentified; speech
  • MM - Multiple speakers; speech

Time (dd:hh:mm:ss) | ID | Transcription
00:03:52:30 | MS3 | Main Bus B voltage nominal, current nominal. AC Inverter 2 voltage, current and temperature nominal.
00:03:52:57 | MS3 | Payload AC Bus 2 on.
00:03:53:04 | MS4 | You have power?
00:03:53:10 | MS3 | Yeah.
00:03:53:15 | MS1 | Wait, that wasn't there before.
00:03:53:23 | MS3 | Rob?
00:03:53:35 | MS1 | I mean that dark spot on the wing leading edge. The right one.
00:03:53:41 | MS2 | Lemme get a closer look.
00:03:53:54 | MM | [Garbled]-a shadow?
00:03:53:57 | MS2 | No, the light’s falling straight on it.
00:03:54:11 | MS3 | Looks like it's in the path of those impact streaks.
00:03:54:31 | PLT | Houston, Independence. Permission to get a visual on the right wing.

Author’s notes:
[1] ITL, the “first vehicle” would be 6SL, first sighted as a test model and later stacked with Polyus. The other two would be the 4M test model, and the 7SL flight vehicle for YMOS-1 mistaken here for a full Energia.
[2] OTL, the US did believe the USSR had a smaller shuttle; this was due to a mix-up of insider information regarding Zenit and the BOR-4 tests, which led to the erroneous conclusion that a Spiral-like shuttle was also under development.
[3] Analogous to the OTL Advanced Launch System (ALS) program.

End of Act 2
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That is a badass Polyus launch,way better than how it looked in OTL.

What’s “MM” refer to in the transcript?