Monday, October 30, 2006

The Basics--And Beyond

What are the things you can't live without? There are a lot of things we think we can't live without--love, productive employment, a place to live, purpose and health, among others--until we find ourselves lacking any of the above and discover that we can, indeed, survive for quite a while, notwithstanding the fact we may not enjoy it very much. Long term, we do need food and shelter, but under most conditions we can get by without them for considerably longer than most of us would ever imagine. Short term, though, what are the things that are absolutely imperative for a human to survive? Assuming the ambient temperature is within acceptable parameters, if short term is described in terms of minutes, you've got one possible answer--oxygen. If you extend short term to a few days, you can add water to the brief "absolute imperatives" list.

When you come right down to it, there's very little that's more valuable to human beings than clean, potable water, and clean, breathable air. I'm speaking in physical terms here; spiritual needs are just as real, in my opinion, and in the long run even more important, but that's not where I'm headed with this post, so for now, I'll stick to the tangible basics--water and oxygen. Let's start with oxygen. Here on Earth, we are part of a built-in exchange system--oxygen for carbon dioxide, carbon dioxide for oxygen. The animal kingdom breathes, and the plant kingdom breathes, in a mutually beneficial exchange, and the whole cycle goes on in perpetuity. It may be contaminated in places, but air is essentially ubiquitous. To a lesser extent, so is water. Water is very scarce in some regions, and too dirty to drink in others, but with two thirds of the planet covered in ocean, and a natural water distribution system in place, which we affectionately call weather, for most people there's enough water to meet their needs. (Sometimes too much.)

Not so in space, of course. Residents of the International Space Station must rely on the generosity of the home world to provide the breathable stuff, and the thirst quenchers. They're shipped up to the ISS in shuttles and rockets, and the water, especially, takes up a lot of precious cargo room in the process. They've been able to get away with this inefficient system for so long because, relatively speaking, the ISS is just a hop off the planet, close enough to make shipping these essentials doable, if not convenient. Any sci fi fan worth their salt, however, knows that if mankind is to reach more distant goals, like the Moon, Mars, or even beyond, there's going to have to be a radical transformation in the way air and water are provided to the space-faring adventurer.

Trudy Bell, writing an article for Science@NASA, tells of a new system so to be installed in the ISS, called Environmental Control and Life Support Systems, or ECLSS ( think eclair, only ecliss), that in many ways will resemble the water reclamation processes described in the Frank Herbert novel Dune. Herbert's book is set on the desert planet Arakkis, where water is so scarce that every possible molecule of it must be captured and recycled. Desert dwellers wear suits specially equipped to catch even the moisture of transpiration and perspiration, so that nothing H2O-related will escape collection and reprocessing. Sounds a bit icky, but that's basically what goes on here on Earth, just on a much larger scale, and you know what they say about desperate times. Anyway, Bell writes that the new system going in on the space station will grab all of the water out of the air, filter in and send it back for reuse. Same goes for the astronaut's urine, except, since the urine has a lot more contaminants, the reclamation rate will be about eighty-five percent, and they will have to jump through some interesting hoops to get the equipment to work.

The way they process the urine is to boil it, turn it into steam, then combined it with the water recovered from the air, and filter it all some more to make it pure enough to drink. According to Bell, using this method, they can produce a half a gallon of water an hour, which more than meets the needs of the three people currently living on the ISS. Sounds simple, right? However, there's a catch. Since there's no gravity in space to make the steam rise, in order to get the steam to separate from the impurities, or "brine," they have to spin the whole kit and caboodle to create artificial gravity. Wild, huh? Something as basic here on Earth as "heat (steam) rises" doesn't apply in space, so they have to go to extraordinary lengths to make it happen. Of course, here on Earth, gravity also comes from spinning, but that's a system God put in place and manages. We really don't have to come up with high tech ways to make it happen.

There are a couple of extra-cool things about this system, "above and beyond" (the pun is lame, I know) just providing drinking water. ECLSS is also designed to provide that oxygen we were talking about earlier:

In addition to providing drinking water for the crew, the water recovery system will supply water to the other half of ECLSS: the oxygen generation system (OGS). The OGS operates by electrolysis. It splits water molecules into oxygen for breathing and hydrogen, which is vented outside the spacecraft.
Nifty, don't you think? Take water, apply electric current, and voila, you get oxygen. That's how they've been doing it on Russian Soyuz rockets, and the (former) Mir space station for years. It's a tried and true method.

One other really cool thing I read about concerns the people who developed the ECLSS system. The are using their expertise to help meet humanitarian needs here on Earth. I followed a related link from NASA, which led me to another NASA article, this one by Katherine Trinidad and Steve Roy, about a project whereby NASA technology is being used to provide clean drinking water for an impoverished Iraqi village, with a broken well pump, and no access to other sources of water. Robyn Carrasquillo, engineering manager of the ECLSS project, and "engineers at the agency's Marshall Space Flight Center in Huntsville, Ala., helped install and test a water purification system in the northern village of Kendala." They've used their own time for the project, which is allowing the few villagers who managed to remain in their small community after the water supply was lost to stay in their homes. NASA-designed equipment is pumping out four gallons a minute for the desperate village!! It must be awfully satisfying to not just further mankind's aims in space, but to also help their fellow men (and women too, of course) here on the "blue marble."

Seems to me that by collaborating to provide this system for the village of Kendala, these NASA engineers are meeting some of the needs on the larger list I made earlier. For the villagers--a place to live, and health. For the engineers--productive employment and purpose. For both of them--the love of their fellow men. Science meets humanity. The best of both worlds. It may not be something we can't live without, but it's certainly something we can all live with.