Following on from why the Space Shuttle sucked, I’m going to do a little summary of manned spaceflight – both where it’s been, and where it’s going.
You’d have to look pretty hard to find someone who didn’t know that Yuri Gagarin was the first man in space in 1961. However, finding someone who doesn’t have a clue what the hell he was flying would be significantly easier. Gagarin made Earth orbit in what was essentially a tin can strapped to a converted ICBM. The tin can was called Vostok, and it was incredibly basic; it was a metal capsule containing the cosmonaut attached to an equipment module with RCS1 thrusters and a small rocket engine to make the re-entry burn. Vostok amuses me because once the re-entry capsule had separated from the equipment module the cosmonaut had no way of controlling his re-entry – no thrusters, no parachutes, no nothing. Well, I suppose they did have parachutes, but only in the sense that the cosmonaut would physically have to eject from the capsule and parachute down before the capsule smashed into the ground. Still, it proves that you can do spaceflight in an incredibly basic way if you’re willing to economise.
The American Mercury program was next; this is slightly better known thanks to Freedom and Hollywood and whatnot. Alan Shepard was beaten by Gagarin’s flight by a mere month, but what the films and documentaries tend not to emphasise was that Shepard’s flight was sub-orbital – i.e. there wasn’t a huge amount separating it from a regular aeroplane flight except the altitude. It wasn’t until 1962 and the third Mercury flight that NASA finally achieved a stable orbit. On the other hand the problem lay more in the Redstone rocket boosters they were using than the Mercury spacecraft themselves; compared to Vostok it was a model of sophistication, with a conical shape for controlled re-entry (this is important because you only have to plaster your heat shield along the flat bottom of the capsule rather than shielding the whole thing as they had to do with Vostok), limited fly-by-wire maneuvering capability and a parachute for a “soft” splashdown into the ocean2. Most of this was down to the direct participation of the Mercury Seven astronauts in the design process – they were aviators3 used to being in control of whatever they were flying, and so they demanded features like a bigger window and a manual re-entry control system.
Mercury and Vostok were essentially proofs of concept. We knew spaceflight could be achieved, and now it was time to do something with it. That something was the space race for the Moon. Pretty much every single thing the Americans did post-Mercury had the final goal of supporting the Apollo program and the Moon landings. By contrast, while the Soviets had the same general objective they were more concerned with space “firsts” – first EVA, first space station, first probe around another planet and so on. This is one of the reasons they went running up the blind alley of the Voskhod programme.
Voskhod wasn’t even a second generation spacecraft – not really. It was simply a Vostok capsule modified to take two cosmonauts instead of one, and it retained most of the limitations of the Vostok capsule. Improvements in the boosters used to carry them into space meant that Voskhod had a braking rocket added which allowed for a “soft” descent on land with the cosmonauts still inside, but otherwise it was basically the same spacecraft. Jury-rigging Vostok in this way meant the Soviets got two of their firsts – first multi-person spacecraft, and the first spacewalk4 – but since Voskhod was a technological dead end it turned out to be mostly wasted effort, with only two flights being made.
Gemini on the other hand was a pure technological testbed for Apollo. There were ten manned Gemini flights over a two year period in 1965 and 1966; not only were these testing the systems and procedures required for multi-person spaceflights, they were also testing the maneuvers that would be necessary for a Moon shot – docking two Geminis in orbit, endurance spaceflights, that sort of thing – and giving the Gemini astronauts valuable experience in these manuevers that they would later find useful on Apollo missions. Design-wise Gemini superficially resembled a larger brother of Mercury, but the internal mechanisms were very, very different. In particular where the Mercury spacecraft combined its critical systems like power and life support into the Mercury capsule itself, Gemini hived these off into a separate equipment module similar to Vostok. This laid the groundwork for the modular construction of Apollo.
Not that the Soviets were sitting around all dejected after the relative failure of the Voskhod programme. They started design work on the Soyuz capsule in 1963, with the first generation Soyuz flying in 1967. Soyuz was intended to be part of the Soviet Moonshot5; the idea was that it’d make up part of a modular spacecraft attached to a lunar lander in the same way as Apollo’s command/service module. Soyuz has the same sort of construction, with orbital and service modules that contain all the stuff the spacecraft needs while it’s actually in space which is then jettisoned before landing to make the re-entry module’s job easier. An unmanned Soyuz capsule even made a test flight around the Moon in 1969. You can essentially think of it as the Russian equivalent to Apollo – and while you’re thinking about that, consider that while it’s undergone several generations of redesigning the Soyuz spacecraft is still flying today ferrying astronauts up to the ISS and back, albeit in a heavily modified form. Imagine what NASA could have done had they stuck with Apollo instead of putting all their hopes in the space shuttle.
Speaking of Apollo, there’s a decent argument to be made that it represents the peak achievement in manned spacecraft design. The modular construction meant that it could be tailored to a specific mission – there’s no reason an Apollo capsule couldn’t make routine flights to LEO just as well as it flew to the Moon – and considering it had to keep astronauts alive during the most insanely ambitious and dangerous missions in the history of manned spaceflight it speaks volumes about how well it was designed that it did an astonishingly good job, with only three astronaut fatalities when Apollo 1 caught fire on the launch pad.
This is why I think Apollo is so amazing (and indirectly, why I think the space shuttle was so terrible). Here is a picture of an Apollo spacecraft.
The big cylinder with the rocket is the service module with life support, power and propulsion systems6. The small cone on top is the command module which contains the astronauts during flight and re-entry. The service and command modules would be launched into space together on top of a Saturn V, and then they’d dock with the lunar module in Earth orbit before switching to a trans-lunar orbit.
Everyone got that? Right. That was spacecraft design in 1969. This on the other hand is spacecraft design in 2012. It’s the proposed design for what used to be the Orion spacecraft, part of the Multi-Purpose Crew Vehicle system that’s supposed to replace the space shuttle. Note the way it looks exactly the goddamn same as Apollo. That’s how good Apollo is: when today’s NASA engineers were asked to design a next-generation spacecraft, they used Apollo as the blueprint.
Aaaaanyway. After the Moon landing everyone kind of lost interest in space flight as a national pursuit, and the design of new spacecraft stagnated. The US launched the last Apollo in 1972 and haven’t made a manned spaceflight that didn’t involve the space shuttle since. The Soviets – and then the Russians – continually refined the design of Soyuz and made great advances for the long-term human habitation of space with their Mir space station, but they too are somewhat stuck in the past as far as manned spaceflight is concerned. China is the only other nation with an operational manned spaceflight program; while people sneer at their Shenzhou capsules as barely being at the Gemini level of technology, you have to remember what I said about the MPCV – NASA is still using the Apollo design after running down the blind alley of the shuttle for the last thirty-five years. It’s the launch rate that concerns me, with the Chinese managing just three manned missions in nine years. They’re not going to make any progress if they don’t physically launch the things into space with taikonauts inside.
So spaceflight has been rather static for the last forty years. It’s only now starting to take off again (har) and the major driving force behind that has come from a rather surprising source: the private sector. More on that on Thursday.
- RCS stands for reaction control system; if you want to make a small adjustment to the trajectory of something flying through space the best way to do it is to squirt a small amount of pressurised gas in the opposite direction and let Newton’s third law do the rest. That bit in WALL-E with the fire extinguisher? That was scientifically accurate.
- American capsules all splashed down into the ocean. Soviet capsules all landed in Siberia or the deserts of Kazakhstan. Why is this? It’s a more a divergence in the cultural design philosophy than anything else — both methods are equally valid in their fulfilment of the main requirement for a spacecraft landing site: that it be really, really, really hard to miss.
- Flying ability wasn’t really necessary for astronauts, except in so far as it demonstrated their ability to handle very complex machines. However what was useful was their complete self-confidence and conviction that they could handle anything, which was a trait common to combat pilots.
- Which nearly went comically awry when Alexei Leonov realised his air-filled spacesuit — which he’d clambered into in the pressurised cabin of the spacecraft — had inflated in the vacuum of space to the point where he could no longer bend his joints to get back inside the airlock. His problems didn’t end there, either; Voskhod 2 overshot its landing site by some 400km and the two cosmonauts ended up spending a very chilly night in the Ural mountains before they could be recovered.
- The Soviet moonshot didn’t fail because their spacecraft were bad. It failed because they couldn’t get their heavy lift rocket launch vehicles working properly before the Americans landed, thus cementing my opinion that Rockets Suck.
- Putting all the critical systems in one place does have a drawback, as the Apollo 13 disaster demonstrated. An exploding oxygen tank damaged the service module, and because the astronauts didn’t know how bad the damage was they couldn’t trust any of the systems contained on board – including, critically, the large propulsion engine that they’d normally be using to adjust their orbital trajectory. If they hadn’t had a convenient set of backups in the form of the lunar module life support systems and descent engine, the Apollo 13 astronauts would have been screwed.