Anyway, during the scheduled hold at T-minus 9 minutes, NASA TV aired an interview with one of the engineers attached to the Water Recovery System (WRS) project, which is finally on its way to the ISS in Endeavour's cargo bay. He explained the process, and where the "reclamation material" will come from, then had the interviewer sample the device's output. The result: "It's not that bad." Despite what they quite accurately termed the "ick" factor.
OK, so I'll admit that I might be a tad squeamish myself were I required to knowingly consume a glass of what, until very recently, had been urine. It's purely psychological in nature, since once the particulates and various chemical compounds our bodies excrete have been removed, it will no longer have either aroma or flavor. (Ever sample laboratory-pure deionized H2O? Flat and very boring.) Yet I'm willing to bet that many of us would still hesitate to take that first sip.
If we stop and consider where our drinking water comes from, every water molecule in every mouthful we've ever swallowed has potentially (and very likely actually has) been consumed by another living creature, to then be released by respiration, decay, or excretion. Living in a city, where drinking water comes from an anonymous source and has been processed in a treatment plant few actually bother to visit, using processes that the average person probably couldn't describe, doesn't compel one to pay attention to what they're drinking. We turn on the tap and (presuming we've paid our water utility bill on time) potable water flows out. Only if some unusual event affects what's in our glass do we take note. In some areas, summer (over)growth of algae in the water-source lake imparts a distinct and sometimes disgusting taste to the water; hydrant flushing can temporarily discolor the water with non-hazardous, stirred up sediment; bacterial contamination can result in an inconvenient but very necessary "boil order" being issued.
Living where one is on a well-and-septic system brings the reality a little closer to home. I am well aware that the waste water from every septic tank, "gray water" drainage field, and barnyard in the area will percolate down through the soil and eventually return to the water table in time, where it will then be pumped back up and flow into our homes for use. Mother Nature really does a remarkable job of removing or neutralizing biologic by-products if we don't screw with or overload her processes.
Once we leave the surface of the planet, however, all bets are off. One cannot take for granted the basic necessities of existence: Air, food and water. You can survive a hell of a lot longer without food than you can without air or water. Conveniently enough, water is composed of two elements that can be separated to produce oxygen (a definite must-have when one is sealed into what's effectively an air tank surrounded by a whole lot of vacuum) and hydrogen (a fuel/energy source).
Humans require a minimum amount of water each day simply to survive; add on more for basic hygiene and for cooking or the rehydration of dried foods. By the time you figure in the additional volume needed for the animals, plants and experimental needs of the scientific team, it doesn't take long to realize that it's not a matter of tucking a few extra water jugs into a locker somewhere; any mission lasting more than a few days will necessitate schlepping a lot of water into orbit. One gallon of water weighs 8 pounds. Multiply that by however many hundreds -- or thousands -- of gallons of water needed. It takes a lot of energy to get that much mass out of a gravity well. (And remember, in a low- or zero-gee environment, the weight may be nil, but the mass is still there when you try to move or stop the object, so getting your water to your destination will still take a fair amount of energy.) Under those conditions, recycling and reusing water on the space station -- much less on future missions to the Moon, Mars, or other destinations -- is a no-brainer. It will also be an absolute necessity for the ultimate survival of the ISS project, on long missions, and at bases established elsewhere in the solar system.
You need to do your research in the low-gravity environment found at Mars Base Alpha? (You know, the one we should be building by now?) You're taking a contingent of, say, 20 along to make the project feasible? You won't be back for 4 to 5 years? You have to schlep all your water along with you, you can't extract it from the native environment? And you're not going to reclaim and reuse as much water as possible from biologic waste and gray water? Guess what: It can't be done. Not with the technology and equipment we have today. Maybe not with any technology or fuel source we might develop within the next 10 or 20 years.
OK, so I could be wrong on that last comment. I don't have the inside scoop on what's in development at NASA, JPL, or any other aerospace-affiliated organization. Maybe you could fill a dozen or more external fuel tank-sized containers, strap them to the current equivalent of Saturn V rockets, and get all that mass successfully transported to its destination. But even if you can, you're not going to be able to take enough H2O to cover any and every eventuality. If you run out of water because you won't recycle, you are going to be seriously screwed.
Don't worry, your coffee won't taste of mouse pee....
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In all fairness, I do have to point out that there is a certain percentage of water that is non-reclaimable, even in a closed environment. So you can't just take a bare minimum of x liters of water and call it good. It's going to have to be x plus some factor that you actually transport. Having that extra water available for use will make life in space much more tolerable. And any amount that you can reclaim and reuse makes the energy costs of getting you to and from your destination more manageable.
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