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NASA Engineers Work on New Spacesuits
NotCoward writes "In labs at Johnson Space Center, away from the buzz about NASA's new spaceship and its new missions to the moon and Mars, a group of engineers are plodding away at another piece of the puzzle: spacesuits. Astronaut apparel has evolved over the decades from Mercury's aluminum foil-looking outfits to the bulky, 275-pound whites now used on jaunts outside the space station. While it's too early in the process to know how the new space suits will look, the space agency is hoping to make new suits both high-tech and low-maintenance."
The chemistry of that seems a little difficult. Human metabolism works by a redox reaction with atmospheric oxygen as the oxidizer. That's convenient for us as we don't have to store an oxidizer in our tissues, only the fuel.
As in any redox reaction, the exhaust -- CO2 in this case -- is a lower energy state. Moving the process in the opposite would require quite a bit of energy. In a small device like a space suit, the only practical source of large amounts of energy is a chemical reaction. So now we're back to needing an oxidizer anyway. Maybe you could find one more convenient than oxygen, but the inefficiencies of the process are likely to undo any gains.
Are you joking?
Mars' atmosphere is a lot thinner than Earth's, and the pressure at surface level is only 0.6% of Earth's. Even if supplied with breathable air, and heating, you wouldn't survive in the martian environment due to the extremely low pressure. The suits *have* to be airtight.
Vacuum cleaners suck. Kings rule.
We could, but the reason we don't re-split in most cases is power.
For example, a spaceship on a journey to mars, powered by a nuclear reactor could indeed use a system to split CO2/H20 back into C, H2, and O2. It'd take loads of juice and likely be quite bulky, but it'd work. You stick the hydrogen into the fuel tanks, breath the O2 again, and either store or eject the carbon. It might even make sense over carrying six months to two years* of O2. This is, of course, assuming that we don't go the organic route and have some sort of greenhouse that'll do the splitting naturally, as well as generate food doing it.
Now, due to said power and bulk requirements, it's cheaper even for the shuttle to merely use CO2 scrubbers and compressed air cylinders to provide life support. This is doubly true for space suits where weight and size are paramount, duration not so much. You're not going to be spending weeks in a space-suit, nor are you going to be spending years in a space shuttle.
*Margins, redundancy, and mission duration.
I don't read AC A human right
For those who are interested, the AIAA covered this [PDF] in the July 2006 issue of Aerospace America.
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
You have already been taken to task about parts of this, but not on one. Keep in mind, that none of the space suits store "bulk" gas. The N2 that is in the air is not used by us. It enters our lungs and generally exits in the same concentrations. All in all, you use the N2 that you entered with. But the CO2 needs to removed and O2 injected. All you store on any of these suits is O2, Of which there is damn little in the martian air. They will still have create and carry O2.
I prefer the "u" in honour as it seems to be missing these days.
You're neglecting the third corner of the triangle. They can design a high-tech, low-maintenance space suit, but it will be monstrously expensive.
Virtue finds and chooses the mean.
Aristotle, Ethica Nichomachea
Some designs under consideration are very sci-fi like. Even retro sci-fi. Currently, we use pressure suits. These are suits with an inner bladder that contains the air, and an outer layer that helps retain the bladder and conform it to the right shape. While they're designed to make it so that the suit is constant volume (because changing the volume takes extra work), you still waste a lot of energy bending the suit. There are two radical departures from this.
1) Hard shell: These suits look like sci-fi powered armor, minus the power. There's already a few suits like this used for deep-sea diving. A hard shell suit is a rigid exoskeleton with smooth-sliding ball joints. The joints are the hardest point of the design, as you can't afford for them to leak, but you can't afford for them to resist your motion much, either. It takes many joints for a good suit to not constrain the wearers' motion too heavily.
2) Skintight: Like in retro sci-fi where everyone walks around in spandex, this is actually a serious design. The tight suit itself provides direct pressure on the body. Even better, the fabric is slightly porous so that you can sweat into the vaccuum of space, so you don't need cooling. There's one big downside that has prevented widespread adoption of such suits: they're currently almost impossible to get on or off. Such a suit, to be practical, would need to be made of a fabric that can change size when exposed to a certain stimulus (electricity, air pressure, etc).
How come things that happen to stupid people keep happening to me?
"But I'd think that it would be psychologically uncomfortable to have your awareness of what is going on to either side cut off for long periods at a time. What if some evil, tentacled creature crawled out of a crater and was heading right for you? You'd never see it." Not really. Many people actually like the narrower point of view. There are many, many commercial divers in the world. Working underwater is much like being in space. Both environments require life support equipment, both can have poor to no lighting so your field of vision is restricted to where you light is aimed. So we know a lot about working in in forgien environments with helmets that provide less than 180 degree fields of view. In space you may not want the wide field, harsh sunlight hitting your face may not be what you need. Gare in the inside of the helmet is an issue too. You do NOT want light hitting the back side of the glas you are trying to look out from. I prefer glack silcon skirts on my mask for that reason -- a clearer, higher contrast view. Put it this way: Have you ever used your hands cupped around your face to peek through a window. You need to block the light that comes in from the sides. I'd not want a fish bowel helmet if there was a light source in back of me or to may side. Which would work out to 75% of the time I suspect these new helmits are designed with input from astronaughts and maybe some divers too.
Mars' atmosphere has no free oxygen, as the element combines readily and quickly. Earth has free O2 because it has plants converting CO2 to O2. Mars' air is mostly CO2, and the air pressure at ground level is measured in millibars, or thousandths of Earth's sea-level air pressure. It's enough to blow dust during energetic wind storms, but is practically vaccuum for us. Think of air pressure at oh, 15 miles above sea level here, wild guess, close enough.
I'm assuming that you've never done hydroponics before, based on what you've written. It's no trivial task. First off, your nutrient solution is typically something like a mixture of calcium nitrate, potassium nitrate, magnesium sulfate, monopotassium phosphate, potassium sulfate, and various other soluable mineral salts. A typical mix may have a dozen or so. This single mix will work fine... for a while. However, the soluable ion ratios get messed up by the plants' selective absorption over time, in addition to plant waste products. On Earth, you typically toss the solution and refill it. Won't work in space. You'll have to use a rather elaborate testing method and fill each of the salts just right, and remove all of the plant waste products. Of course, not all waste products will be in the soil. For example, plants release ethylene gas. It's far more deadly to plants than carbon monoxide is to humans, and much harder to detect/extract. Commercial greenhouses deal with this through venting into the atmosphere and taking in fresh air. Won't work for you here.
Anyways, back to the minerals. Where are you going to get all of them? You can't just "compost" plants in an isolated environment; waste gasses will build up quickly. Just one example: ammonia. Are you going to just vent it? Then you're losing your precious nitrogen. Going to refine it? Then you'll need a whole refinery, just for that one waste product. What you get out of compost is *not* something that you can just throw into the water for your hydroponics solution, anyways.
How come things that happen to stupid people keep happening to me?