Wednesday, 27 August 2003

Manned Space

I've always been a strong advocate of the manned space programme, and continue to be. But with some very big caveats.

First, we should stop pretending that the manned space program is anything to do with Science. It isn't. Or rather, with only one exception - more on that later - , our technology is now at the state where a manned mission costs vastly more than a dozen, or even a hundred, unmanned missions that would get the same quality of scientific data.

For the cost of sending a Scientific exploration team to thoroughly investigate a small patch of, say, Mars, we could put literally hundreds of rovers, aircraft, and fixed landers a la Viking down and cover a vastly greater area, albeit with less flexibility in focussing on anything interesting we find.

For the cost of the ISS - the International Space Station - we could have done so much more in the way of Scientific research that it makes no sense whatsoever, if Science was the only goal. As regards Space Manufacturing in microgravity fields, you must remember that the ISS is not in "zero gravity", it's in "very small gravity". It's not far enough out to remove the effect of tides from the Earth. But far more importantly, the whole structure moves and vibrates every time any of the crew so much as sneezes. The effect is enough so that certain experiments "on" the ISS are actually set adrift on the end of a tether, so they won't be affected by this. As regards the old Von Braun idea of assembling interplanetary vehicles in a convenient permanent rendezvous, refuelling them and sending them to the Moon, Mars etc., the Apollo and Gemini programs showed conclusively that space docking could be done anywhere, even Lunar orbit. And the Mir programme showed the dangers of docking to a big, lumbering structure in case anything went awry. Any vessel returning to Earth from, say, the Moon will be travelling at pretty much Escape Velocity, that is, about 25,000 KPH. This is because it's "falling from an infinite height", or as near as makes no odds. The Apollo capsules came in like bats out of hell, far faster than any previous re-entries for this very reason. It makes more sense to carry X kg of extra mass to re-enter, than 5X Kg or more of fuel to slow down to Low Earth Orbital speeds to rendezvous with a space station, then re-enter using another vehicle.

I always knew that it was more expensive to send a man to do a robot's job, but always believed that the flexibility of a human being more than made up for it in many missions. But that was before I worked on FedSat, where I found out how much autonomy we could be giving to various small, cheap satellites. The cost differential (robot vs manned) is somewhere between a factor of 10 and 100. So we shouldn't be comparing the benefits of 1 manned mission vs 1 robotic mission, we should be comparing 1 manned mission with possibly 60 or 100 robotic ones.

I repeat; if Science is the only justification, then anything a man can do, 50 or 100 robots can do better.

I've personally never been impressed with the "because it's there" argument for exploration. Nor the old saw about "Name one thing a Man can do that a Robot can't : Plant a Flag". If only because an early Lunik did exactly that, some 10 years before Apollo 11.
U.S. Rejects any Flag Planting as Legal Claim to Rule Moon, N.Y. Times, Sept. 14, 1959, 15 I, at 1, col. 8, 16, col. 3;

But Robots aren't sexy. The old saw went "No Bucks, No Buck Rogers", but the converse is more true: "No Buck Rogers, No Bucks." The incremental cost of the Apollo 13 mission (according to the Artemis Project) was about US $375 Million. Compare that with the international box-office receipts of the film "Apollo 13", US $ 334 Million.

Experts agree that most of the technology for a manned trip to the Red Planet is already available. The mission would be long, costly and not achieve much other than to plant a flag and do science that could in any cast be mostly duplicated by robots.

But it would still breathe life back into the space dream, the vision of man carving out his destiny in the cosmos.

"The future of man in space is a matter of political will as well as science," said Sims. "A mission to Mars needs the kind of will that (former US President John F.) Kennedy brought to the Apollo programme."
- From "Annus horribilis for space exploration?".

So there's a very practical reason to continue manned missions : because there's funding for it.

From an ethical viewpoint, that sucks as a reason. There is, however, a far better one. The one Scientific experiment thata robot cannot perform, and a human can, is "How do Humans fare in Space?". Because we are stuck on one small, fragile chunk of rock at the moment. One passing comet or chunk of rock in the wrong place at the wrong time, and we're merely a blip on the fossil record. If we wish to preserve Earth's biodiversity (and incidentally our own skins), we must spread out a bit. In the short term, have several self-sustaining arcologies/ecologies throughout the solar system. In the long term, no Star lasts forever, and the Sun is more variable than most of its ilk. Within the timescale that Evolution starts to operate, and H.Sapiens becomes something else, we should have spread ourselves a bit wider. Assuming we'd be prepared to take 99% losses, we could probably rig up some interstellar colonisation vessels within the next century, and no need for a hyper-drive or doubletalk-generator, just a self-sustaining self-contained ecology that can make a trip of a few tens of thousands of years. If we really went at it, storing all the anti-matter that's currently wasted at CERN and other supercolliders, and built a few thousand more of them, then maybe we could so it in thousands rather than tens of thousands.

Now this isn't feasible - we'd have to vastly increase the world's power output and store it for centuries just to get something to a decent fraction of lightspeed - say 1/1000 of it. But given a few thousand years, who knows what we'll be capable of? But only if we take the first steps. It doesn't have to be now, it doesn't have to be us. Someone will do it. The point is, is our culture worth preserving, or will the future belong to other people and other societies - people who have got their act together, but who may not have quite the same regard for individual human rights that we do ?

From the long-range nebulous future, to the hard realities of the present. The 1960's aircraft with 1970's avionics that is the Shuttle needs mending with a new one, ie replacing. It's too expensive and with too few airframes to fly as anything other than as an experimental aircraft. We need not tens of flights, we need hundreds, not to transport anything, but to get the reliability up to something approaching commercial air standards.

It's also a hybrid - it transports people, but also is a moderate-weight high-volume lifter. The replacement should be a combination of a heavyweight lifter in the Energia/Saturn class, plus a smaller vehicle specialised in transporting people around the joint. Whether this vehicle should be re-useable or disposable is another matter, as is whether it should be winged or ballistic. But it should be flown often enough so that the reliability can exceed that of the Shuttle and Soyuz - which is at best, 98%. Either way, more astronauts will die, that's not avoidable. But at the end of it we'll have a true Space Transportation System that's as reliable as, say, a DC-3.

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