04 August 2015

Dreaming a Different Apollo, Part Two

Space Shuttle Mission-62: Discovery awaits the imminent arrival of its crew, August 1994. Image credit: NASA
In January 1978, President James Carter announced a surprise decision: NASA's Space Shuttle, then under development but plagued by delays, cost overruns, and technical snags, would be redesigned to launch and land without a crew on board. A spacecraft based on the tried-and-true Apollo Command and Service Module would launch astronauts to the Orbiter in space. They would enter the Orbiter through a docking unit in the Orbiter Payload Bay and use it as a mini-space station for scientific experiments and satellite servicing. Mission completed, the astronauts would return to Earth in the expendable Apollo, then the Orbiter would return to Earth for refurbishment and reuse. Carter justified his decision by pointing to the Shuttle's lack of credible crew escape systems and abort modes.

Carter's 1978 decision piqued the ire of spaceflight purists in a way that even the Sortie Lab decision of 1972 had not, for it turned the rationale for the Shuttle completely upside-down. The Shuttle had been conceived originally as crew rotation and resupply vehicle for a Saturn V-launched core Space Station. After President Richard Nixon refused to fund the core Station and scrapped the Saturn V, NASA studied a Shuttle-launched Station until it became clear that no Station would receive Nixon's blessing.

Deprived of its true purpose, the Shuttle Orbiter became a piloted spacecraft meant to replace all existing expendable space launch vehicles. It would, NASA promised, dramatically reduce the cost of spaceflight, ushering in a new age of space development. It would also reduce the cost of satellites by servicing them in orbit, serve as a short-term space laboratory by carrying in its Payload Bay a can-shaped Sortie Lab module, and make space readily accessible to non-astronauts.

The 1978 decision to turn the Shuttle into a robot spacecraft ceased to be controversial on the morning of 28 January 1986, when the Orbiter Challenger was destroyed a little more than a minute into Space Shuttle Mission (SSM) 25. Had astronauts been on board, they would have been unaware of the Solid Rocket Booster malfunction that was the root cause of Challenger's destruction. Had they somehow learned of the malfunction, they would have been unable to intervene and would have been trapped at least until the Shuttle stack's twin Solid Rocket Boosters had spent their propellant and detached. That would have been too long, for Challenger was destroyed as its Solid Rocket Boosters still burned.

As it was, Challenger's five-person crew for SSM-25 watched as the automated spacecraft they had been meant to board in orbit for a two-week stay was torn apart by aerodynamic forces and tumbled in fragments into the Atlantic. The Solid Rocket Boosters emerged still firing from the fireball created when the Shuttle's large, fragile External Tank broke up, spilling its liquid hydrogen and liquid oxygen propellants. The Solid Rocket Boosters each painted a twisting smoke-trail across the blue Florida sky until a Range Safety Officer sent the radio command that destroyed them.

As Challenger disintegrated, the Astronaut Transport Spacecraft (ATS) meant to launch the SSM-25 crew into orbit the following day stood atop a Saturn II expendable rocket on nearby Pad 39B. The ATS was an Apollo Command and Service Module spacecraft redesigned to carry five astronauts. The Saturn II rocket comprised the top two stages of the Saturn V - that is, the 33-foot-diameter S-II and 22-foot-diameter S-IVB. It included six uprated J-2 engines - five in its first stage and one in its second - and six small solid-rocket boosters evenly spaced around its base. Without an ATS on top, the Saturn II could launch a 20-ton payload.

After Challenger, some called for an end to unmanned Orbiter flights. They pointed out that the ATS/Saturn II combination included a sizable cargo volume in the tapered shroud that linked the base of the ATS with the top of the Saturn II S-IVB. They referred to early 1970s NASA and contractor studies that showed that increasing the number of solid-rocket boosters to 10 would permit the Saturn II to launch both the ATS and up to 20 tons of cargo .

President Carter, since his election in November 1984 the first President since Grover Cleveland to serve non-consecutive terms, surprised many by declaring his support for the Shuttle. This should perhaps not have come as a surprise, given that it had been Carter who made the 1978 decision to launch and land the Orbiter without a crew. The "come-back President" pointed to the Challenger accident as the vindication of his 1978 decision, and called for continued unmanned Orbiter flights on the grounds that upgrading the Saturn II would not replace all Shuttle capabilities. It is widely assumed that he also sought to continue the unmanned Orbiter flights to preserve the thousands of jobs the Shuttle Program had created.

In August 1986, Carter signed off on NASA's post-Challenger plan to redesign the SRBs and begin construction of two new Orbiters. This would increase the total number of Orbiters in the Shuttle fleet to four, enabling more downtime for inspections and upgrades between flights. To pay for the new Orbiters, Carter reduced the number of annual Orbiter flights to three from the six planned before Challenger was destroyed. As each new Orbiter came online, one additional flight per year would be added, so the four-orbiter fleet would eventually fly five missions per year.

In the meantime, the Hubble Space Telescope reached orbit in May 1986 atop a Saturn II without an ATS. Repairing its flawed optics became a goal for one of the first post-Challenger Shuttle missions. A Saturn II/Centaur launched the third Radio Relay and Tracking Satellite to geostationary orbit in July 1986, enabling for the first time continuous contact between orbiting spacecraft and flight controllers and researchers on the ground.

A Department of Defense-sponsored ATS solo mission designated SSM-X5 launched in December 1986 with a three-person crew to test polar-orbiting missions. (SSM-X1 through X4 had been Orbiter and ATS test missions in the 1980-1981 period.) Shortly after its return to Earth, new NASA Administrator Sally Ride announced that the Defense Department had opted to forego future Orbiter/ATS flights in favor of ATS solo flights.

The Shuttle Orbiter Enterprise soared into space in September 1987 to start the SSM-26 "Return-To-Flight" mission. Its five-person crew arrived in the SSM-26 ATS two days later. The astronauts spent three weeks on board Enterprise.

Columbia reached orbit in November 1987 to begin SSM-27; after its crew docked their ATS and boarded, they piloted the Orbiter to a rendezvous with the Hubble Space Telescope. Through a series of ambitious spacewalks, the astronauts corrected its faulty optics. They returned to Earth after 10 days in orbit. Columbia landed two days later.

Enterprise reached orbit the next time in May 1988 for SSM-29, but returned to Earth early after the Saturn II rocket bearing the SSM-29 ATS malfunctioned shortly after clearing Pad 39A's lightning mast. The ATS's Launch Escape System activated and pulled its Command Module free of the disintegrating Saturn II rocket. The five astronauts on board were uninjured. They would reach Enterprise to carry out SSM-29R in May 1989. The ATS/Saturn II combination had a flight record going back to the first Apollo Saturn V flight in November 1967, so troubleshooting the J-2 engine malfunction that destroyed the SSM-29 Saturn II and returning the system to flight needed only a few months.

The new Shuttle Orbiter Discovery flew an uncrewed orbital test mission (SSM-X6) in December 1989. In October 1991, the new Orbiter Endurance performed a nearly identical test mission (SSM-X7).

Endurance was the first Orbiter upgraded to permit a 12-week orbital stay and docking with two ATSs at one time. It carried out its first long-duration mission (SSM-60) and received two ATSs between mid-April 1994 and mid-July 1994.

Shortly after Columbia's retirement to the National Air and Space Museum in mid-1995, the new long-duration Orbiter Adventure joined the fleet. It would be the last Orbiter constructed and the last retired; its final mission was SSM-90 in February 2003.

By then, the U.S.-Russian-Chinese-European-Japanese-Brazilian International Space Station had become operational, and NASA and Europe had begun flight tests of the jointly developed Hermes shuttle, which became operational in June 2009. NASA retired the ATS in July 2011, ending 43 years of Apollo and Apollo-derived spacecraft missions.

A note on the Presidents: In this alternate timeline Ronald Reagan defeats James Carter in November 1980, but falls to an assassin's bullet (as he very nearly did) in April 1981. His Vice President, George H. W. Bush, finishes Reagan's term, but Carter narrowly defeats him in November 1984 after Bush's Vice President, Alexander Haig, announces a third-party candidacy that draws votes away from the Republican incumbent. Carter declines the nomination in 1988, in part because of Constitutional questions, and Republican James Thompson of Illinois defeats Carter's Vice President, New Jersey Democrat Bill Bradley, to win the White House. Thompson's two terms (1989-1997) see the collapse of the Soviet Union and the start of the International Space Station.  

Sources

The Unmanned Shuttle Decision: Prudence and the Presidency, John Logsdon, NASA, January 1999, pp. 36-49, 53, 111

SSM-25 Press Kit, NASA, December 1986

SSM-27 Press Kit, NASA, November 1987

Enterprise, Discovery, Endurance, Adventure: NASA's Orbiter Fleet, NASA Facts, December 1996

Chronology of Space Shuttle/Astronaut Transport Spacecraft Missions, 1980-2011, David S. F. Portree, NASA, 2012, pp. 20-22, 26-28, 33-34, 37-40, 45-55, 61-63, 88-91, A-13

15 comments:

  1. Great work as always!

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  2. I found an error in this post —— the 1st I ever saw on your blog:

    You have the Saturn Ⅱ consist of the S-Ⅱ-Stage and the SⅣB-Stage of a Saturn Ⅴ. I believe that you meant the SⅠC-Stage and the SⅣB-Stage of a Saturn Ⅴ.

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  3. I make gobs 'n gobs of mistakes, but this isn't one of them - well, mostly. There was a proposed Saturn variant between the Saturn IB and the Saturn V called the INT-19, which used an S-II first stage and an S-IVB second stage. Thing was, it needed either J-2 engines modified for sea-level ignition or a new kind of engine in its first stage - plus, to get a meaningful payload, it needed some number of Minuteman missiles as Stage 0 strap-ons. I waved my magic wand and did away with reality. I mean, I could get away with not saying anything about the first stage J-2s - they remain J-2s even with sea-level modifications - but omission of the Minuteman strap-ons is a bad thing. I throw myself on upon the mercy of the court. :-)

    dsfp

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  4. Great post, David. This alternate schedule reminds me of the Soviet plans with the Buran space shuttle, but I guess that was precisely your intention. The 1K-2 spacecraft -also known as Burya- was supposed to carry out a similar mission in 1991, but with Soyuz instead of Apollo, of course.

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  5. Daniel:

    Thanks! Now that you mention it - I honestly didn't remember that Soviet plan, but that must be where I got it from. The difference here is that there'd be no intention to ever launch or land a crew in the Orbiter (though I suppose that might be seen as a contingency option). I see it as the President deciding the Shuttle was a lemon and seeking to make lemonade. In truth, I don't see Carter ever doing that. To make some of these things work, one has to replace the existing President with a changeling.

    dsfp

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    1. ¡Oh no! ¡Changelings! ¡Get the Elements of Harmony!

      After the events of the CutieMarkChronicles, the 2 new friends of Fluttershy and Rainbow Dash converse for the 1st time:

      Rainbow Dash:
      > "¿Why do you talk so softly?"

      Flutershy:
      > "Because I am a little hoarse."

      Delete
  6. The INT-19 seems silly. That is why I interpreted this a a stage-mixup. Using an SⅠC-Stage would allow one to launch the whole Apollo-Package of a Saturn Ⅴ, with the Lunar Module replaced with cargo, without additional boosters. Since one does not need as much fuel in the Service-Module as one does for a Lunar mission, one can place more cargo in the Service-Module in the place fuel.

    I have my doubts that we need a Shuttle, but the way I would do the Shuttle is to replace the SⅣB-Stage of a Saturn Ⅴ with the Shuttle thus making the Shuttle safer. Since the Saturn Ⅴ would lift the Shuttle to orbit, one can replace its engine with engines burning hypergolic fuels, place fueltanks in the Shuttle and have a more spacecapable Shuttle, which although it generally lands as a glider, can, in emergencies, do powered landings.

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    1. After doing research, the design I propose is the Saturn INT-20. It could launch 60 tons of cargo into LEO. That could be the Apollo-Package with the Lunar Module replaced with cargo for manned missions or a very large satellite or multiple smaller satellites for unmanned Missions.

      Mine idea for launching the Shuttle using a Saturn Ⅴ is closest the the Saturn-Shuttle, but the Saturn-Shuttle has the external fuel-tank on-top of the SⅠC-Stage, while I would use an S-Ⅱ-Stage and place the Shuttle on-top of the S-Ⅱ-Stage, thus replacing the SⅣB-Stage.

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  7. INT-20 seems to have been pretty well known, which is one reason I went with the "silly" INT-19. More fun to introduce lesser-known rockets. But the main reason was economy. It seems to me that reviving one kind of engine - the J-2 - would be cheaper than reviving two kinds. Plus, there might be a political reason for avoiding S-IC development. INT-20 is closer to being a Saturn V than INT-19. If someone wanted to make it more difficult to revive the Saturn V, then INT-19 would be the way to go. You'll note that I changed my text to include the Minuteman-based Stage 0 boosters, by the way.

    January 1978 was a late date to be redesigning the Shuttle. That wasn't Carter's aim. He accepted the Shuttle design he had inherited and applied what amounted to a low-cost fix (launch the crew separately in a capsule with an escape system). It was a low-cost fix because it didn't require Shuttle redesign beyond adding enough automation to enable the Orbiter to open its payload bay doors to expose its radiators, maintain attitude, and lower its landing gear. It was perhaps a more likely fix than some because in January 1978 the final Saturn IB/Apollo CSM flight was only 2.5 years in the past.

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    1. Let me clarify that you are not silly.

      It is just that although Liquid-Hydrogen/Liquid-Oxygen-Engines generates an high specific impulse, because of the low density of the hydrogen, one can only generate so much thrust. The most important job of the 1st stage is is to get the rocket off of the ground and going. For that reason, hydrocarbons/Liquid-Oxygen makes more sense.

      Since the upper stages only have to accelerate the spacecraft, as opposed to breaking contact with the ground, Liquid-Hydrogen/Liquid-Oxygen is the perfect sort of engine.

      The tradeoff between thrust and efficiency is 1 of the most vexing problems in designing Single-Stage-To-Orbit.

      Space-X currently works on Hydrogen-engines for its upper stages. This would increase payloads and decrease costs.

      If one settles for 2 stages, Hydrocarbons in the lower stages and Hydrogen in the upper stage, is the way to go.

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  8. Yes, I am silly, and quite proud of the fact.

    The Minuteman solids would give the S-II first stage extra thrust, just as the Shuttle SRBs shoved that honking colossal LH2/LOX stack off the pad. Because they were relatively small, one could tailor the number of Minuteman boosters to the mass of the payload. From what I can tell, you'd not want fewer than four solids, and the practical upper limit would be 10. I could have that wrong, however, since I'm not sure of the thrust the bottom of the S-II stage could bear.

    I'm assuming that the Minuteman solids are cheap and that that is part of their appeal. Also, that for environmental reasons a big RP-1/liquid oxygen first stage is frowned upon. And, Boeing at Michoud built S-IC stages; Michoud was converted to ETs for Shuttle, so there'd be facilities costs to make room for the S-IC again at Michoud or built a new S-IC assembly facility somewhere else.

    Plus, as I mentioned before, there's the J-2 commonality factor and the political problem of building a rocket too similar to the Saturn V. Basically, what I'm trying to do here is to create some semblance of the weird political environment that surrounds many space decisions.

    I agree with you that the INT-20 would be a better choice from an engineering standpoint.

    dsfp

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    1. Ah, the designed by committee and planned to be built in as many congressional districs as possible. That explains everything.

      About the environmental impact of hydrocarbons versus solid rockets, the solid rockets inject hydrochloric acid straight into the ozone-layer. Free-radical chlorine is bad for ozone.

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  9. I'm not sure about the altitude at which the SRBs would be dropped and how that would affect atmospheric chemistry. I do know that every time an SRB fires at KSC, the pH in the swamps and lakes in east-central Florida goes haywire. Apparently this would be enough to kill many fish and amphibians, but the east-central Florida critters appear to have adapted when no one was looking.

    I like your characterization - committee-designed and Congressional districts - that's exactly what I mean. That said, in a completely logical world the INT-20 would be the best chose and no one would mind that it could be upgraded to re-create the Saturn V.

    dsfp

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  10. Great job love alternate history, but President Carter would ever serve non-consecutive terms

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  11. Quite probably you are correct, but I thought that was a fun detail to throw in. Most people didn't expect that Grover Cleveland would get a second term, either. Jim Thompson, by the way was Illinois's longest-serving governor. He recall folks often thought he should run for the White House, but was happy governing Illinois. He was a more liberal Republican than Reagan but not as liberal as Nelson Rockefeller.

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