Wednesday, April 20, 2011

Space travel - behind the curtain

kw: book reviews, nonfiction, space travel, astronauts

I want to comment first on the closing words of Packing for Mars: The Curious Science of Life in the Void by Mary Roach.
"Yes, the money could be better spent on Earth. But would it? Since when has money saved by government redlining been spent on education or cancer research? It is always squandered. Let's squander some on Mars. Let's go out and play."
Squandered? True, but whether the machines and men go to Mars or other machines and men go to Afghanistan or Libya, the dollars are spent right here! People complained in 1969 about the "millions of dollars left on the Moon" by the astronauts when they returned to Earth. A $1,200 Hasselblad camera was one item left behind: "What a waste!" It would have cost much more than $1,200 to lift from the Moon back to Earth, but more than that, every single dollar spent for that camera, its marketing and procurement, and for everything else including the fuel and equipment that took the astronauts to the moon and back, was spent on Earth, primarily in the good old U S of A. We spent a trillion dollars on wars in the past ten years. Where is the money? Right here! It was spent right here and circulated in the US national economy. OK, EoR (End of Rant).

Packing for Mars is a great read that delves into all kinds of aspects of getting people into space and keeping them from dying there, and getting them back. Astronauts need to be rather different from most of us, for example. They have to be preternaturally smart, yet capable of enduring huge doses of boredom. Great self-starters, but tolerant of micromanagement because every tiny sub-task of every bit of work is scripted beforehand. They get autonomy only when things go wrong. Yet this doesn't give them much motivation to "help" things go wrong, because there are so many ways to go wrong in a fatal way, and so few ways to survive errors.

Life without gravity seems idyllic; we all dream of flying about, weightless. In a microgravity environment, though, just trying to take a drink can kill you. Those videos of astronauts that made a little ball of water, then ingested it? They had to practice a lot, with someone watching and ready to help them get the water out of their nose before they suffocated. Astronauts-in-training get nausea-control training, and still a third to half of them vomit the moment they first see someone floating upside down, or find themselves visually upside down or sideways and an odd food smell wafts by. And floating vomitus is even more dangerous than floating water. It burns while you're wiping it off. Not for nothing is the C-9 plane used for zero-g training called the Vomit Comet.

Ms Roach got a ride in the VC/C-9, and fortunately, loved it, except for the 2-G intervals between 20-second 0-G sections of the ride. When your gravity meter is going 0-2-0-2-0-2-0-2, you start to wonder just why you signed up for this ride. You have to start out absolutely adoring roller coaster rides; there is no guarantee that you'll still like them afterward. But the VC gets a lot of use because every piece of equipment has to be tested to be sure something weird doesn't happen when the G-meter reads zero.

So if water can kill you, how ya gonna bathe? Usually, they don't. An aspect of retrieving a space capsule and helping the astronauts out of it that didn't make it into the press was the incredible smell. There is a way to sponge bathe in the ISS, as there was in MIR, but nobody likes it much. But a hot shower, with water squirting everywhere? A formula for a capsule full of drowned crew.

And so it goes. Zero G erodes your bones, and nothing they have tried has been able to alleviate it much. And if sex is even possible without gravity to help a couple stay in contact, NASA isn't telling, and neither are the other space-faring nations and agencies. "Everybody" is certain it's been tried. No tales have been told.

So, we're faced with getting several humans of some average size to Mars and back, in a mission that'll take about 2.5 years. Call it a bit less than a thousand days. Food: 1.5-2 pounds daily (0.7-0.9 kg), or up to nearly a ton per person. Water: twice that amount, unless it can be efficiently recycled. Oxygen: midway between, say another ton or ton-and-a-half per person, again depending on whether it can be recycled by less massive machinery and chemicals. Then you have to absorb carbon dioxide, and the chemicals and machinery to do so come to more tons.

An aspect not covered, nay, barely mentioned, is radiation exposure. I found this article in New Scientist, which points out that a Mars mission will expose a person to more than two sieverts, assuming no extra solar flares pop off during the mission. A sievert is about a thousand CT scans. Worry #1: retired astronauts getting cancer, lots of it. It is probably best to use the oldest astronauts who are fit enough. Worry #2: non-proton cosmic rays do lots more damage than the proton and electron kind, and are prevalent enough that an astronaut's brain could lose an IQ point per month. Send up a genius, get back someone quite ordinary. Don't bother sending up an ordinary bloke; you'll get back someone who has forgotten how to read.

If this last item can be overcome, such as by having the crew encased in fifty tons of food and water on the way up, and in fifty tons of excrement and "used water" by the time they are back, then the trip is worth it. Forget the dollars. The human instrument is still the one that causes all the trouble. I vote for designing a rocket motor that goes ten times as fast! Get 'em there in thirty days, not 300, and get 'em back equally quickly. While they are there, have 'em dig in so they can at least sleep underground. Better yet, send a robotic digging facility first, so they arrive to a ready-made "subway tunnel" to live in. Now that's a mission worth fighting for!

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