July 14th, 2005

Brad @ Burning Man

The Spaceship You Have (part 1)

To paraphrase Donald Rumsfeld, you go to space with the spaceship you have, not with the spaceship you want. I'm not surprised that yesterday's Space Shuttle launch was cancelled. In fact, I'm kind of relieved. As I've said before, the thing is a lemon. What's more, I've said all along that it was a lemon when it was built. Now, this is a good time to take advantage of one of the few up-sides to getting this old: there are things happening now that make sense to me because I was paying attention decades ago, before some of you were born, when the events leading up to them happened. So this is the story of how we ended up with such a miserable dog of a manned space flight program. There is remarkably little evil in this story, by the way. What little evil there is has nothing much to do with the space program itself. Nor is there an awful lot of obvious stupidity. We got to this point because (mostly) good people, working under inescapable real-world constraints, made the best decisions they were capable of. Their best wasn't anywhere near good enough, but that doesn't mean that they were wrong.

If you went to school in America, you were taught that the "father of space travel" is American Robert Goddard. I'm told that if you went to school in Russia or any of its former Soviet "client states," you were taught that the "father of space travel" is Konstantin Tsiolkovsky. Both claims are rubbish. Tsiolkovsky never built anything, and almost everything that Goddard built blew up. The true father of space travel, the man who perfected the rocket engine, the man whose designs are still used with only minor technical refinement up to this day, was a Nazi SS officer named Wernher von Braun. And in the last days of the European part of World War II, the American and Russian armies were abandoning other military goals to race each other towards von Braun's base in Peenemund, Germany.

Von Braun, a fervent Nazi and like all Nazis, a dedicated anti-Communist, was afraid of the Russians and unwilling to work for them. So he persuaded his top engineers to join him, and raced westward to defect to the Americans rather than risk being captured by the Russians. (That von Braun and so many of his team were loyal Nazis posed an interesting problem for the US: US law prohibited Nazis from entering the US. The CIA had to set up a covert operation called Project Paperclip to sneak around occupied Germany trying to "launder" all evidence against any Nazis they wanted for technical or espionage reasons.) Von Braun and his team put the Americans in the "space game." As in Germany, though, he wasn't allowed to work on what he wanted. What he wanted was to build vehicles with which to explore space. What he got put to work doing, instead, was building nuclear missiles, just as the Germans had put him to work building V-2 rocket bombs for the Battle of Britain.

But from 1952 to 1954, von Braun (and others including science fiction author Willy Ley, with illustrations by science fiction cover artist Chesley Bonestell), laid out a plan for how human beings could explore and eventually colonize outer space, in a series of articles in Collier's Weekly magazine entitled "Man Will Conquer Space Soon!" As with everything von Braun did, the math and the engineering are impeccable. You see, there's a basic problem with the physics of long-distance rocket travel. To go higher, farther, or faster you need more fuel. Which adds more weight. To lift more weight, you need more fuel. Which adds more weight, ad infinitum. To get to the Moon in a hurry, we used an expensive, fragile, and impractical solution: increasingly smaller disposable rocket "stages." Just to get to orbit we used three disposable stages. Then a fourth stage was used to boost the combined lander/return vehicle to the moon. Then yet another disposable stage was used to land on the Moon. Then one more disposable stage, the size of a handicapped bathroom stall, was used to lift off from the moon; as soon as it reached lunar orbit, it was thrown away. Then the Earth-orbit-to-lunar-orbit rocket used the last of its fuel for the return trip to Earth orbit and then it, too was thrown away. Finally a tiny little bitty re-entry capsule, just big enough for the three guys to lie down in and to hold its own parachutes, was the only part of the space ship to return to Earth. Why so many disposable parts? Because it lets you throw away empty fuel tanks, and even though those fuel tanks were built of the lightest, thinnest, most expensive metal alloys available, every tiny little bit of weight saved was essential.

Von Braun preferred a more elegant design, one that would take longer to build but would be more practical: build it in orbit, in pieces. You can lift a ridiculous amount of weight per trip into orbit with fairly simple, cheap rockets. The US and Russian and French space agencies/companies do it all the time for communications satellites and such. So the von Braun approach involves sending up a tiny little improvised construction shack and a couple of guys with wrenches. Then send up a bunch of mostly-empty rockets. They only need to carry the construction crew's lunches and such; the real payload is the empty fuel tanks of the rockets, which once vacuum cleaned make perfectly good expansion space for the construction shack, turning it into a loading dock that can receive construction parts for the real space program. Use super-cheap disposable rockets to send up pre-fabricated sections, supplies, anything heavy. Use expensive space-capable aircraft, a lot less frequently, to rotate crews. The crews' first priority is to build permanent orbital housing for the workers, something big enough to spin for simulated gravity. Once you have that, you can station more permanent construction crews. Use the nearby floating loading dock to receive shipments, and as a "dry dock" for building the spacecraft that will travel to other planets. Send those spacecraft up in sections to be assembled. Send the fuel up in multiple loads. Once you have the capability to do that, you can send human beings basically anywhere in the inner solar system.

So you see? The Shuttle was never intended to be a stand-alone spacecraft. It was intended only as a crew-transfer module for the International Space Station, and ever since the early 1950s it was planned that unmanned Big Dumb Boosters would do all the heavy lifting from the surface to Earth orbit. So how did we get from this simple, elegant, practical design, one straight from the pen of the greatest rocket engineer who ever lived, to the mess we have today? Ah, well, that part I lived through, and I was a space-flight fanatic during the relevant years, so I paid close attention and I remember this part really, really well. I'll tell you about it tomorrow.