Wednesday, April 23, 2014

The Power of Pee....in Space!

You and I usually don’t think much of our pee, we just dispose of it in a toilet (or wherever nature calls in a boy’s case) and let the sewers deal with it. but astronauts on the International Space Stations are seeing it as a bit more valuable than most. To date, it costs NASA about $33,000 per kilogram to launch materials into low-Earth orbit (LEO) or to be able to reach the International Space Station; but the final frontier does not end in LEO, and the amount of money it would cost to get materials outside of Earth’s orbit would reach staggering amounts.
Turning to urine is one the the possible solutions to the problem, made mostly of water, urine can be reclaimed for nutrients and also electrical power. Water from urine is currently recovered at a rate of 75%, but with the efforts now underway, recovery rate could increase to 85% by next year, and eventually 100%. Crews on extended space missions recycle the water used, the biggest source being from their urine, an individual astronaut producing more than 1.5 liters per day, making up 81% of the space stations waste-water. Urea, the nitrogen rich compound found in urine, is currently disposed of on space stations, but can be converted into ammonia and inserted into a fuel cell producing a small charge. Urea is produced through the process of osmosis, separating the molecules of water and urea as well as other small dissolved molecules. The resulting solution containing urea, is put through a device called a bioreactor, which contains charcoal soaked with urease, an enzyme that breaks down urea.
About 86% of that solution is actually converted into ammonia, which is packed into a battery like fuel cell, and can convert the ammonia into nitrogen and water, emitting power. The power emitted is not much, about 0.2 volts, and a current of 2 milliamps, but again there is room for improvement.  This small output places skepticism on the project, or so believes Layne Carter, a systems engineer at NASA’s Marshall Space Flight Center in Huntsville, Alabama, “the limited amount of power that might be harvested from the team’s new process might not recoup the effort or expense.” So the question remains, is all this effort really worth drinking your own pee?

Posted By Thomas Flores (11)

4 comments:

  1. This was a cool read. I'm curious about those numbers at the end, are the 2 volts and 2 milliamps per astronaut per day? Maybe it would be more efficient to save up the urea until it reaches a level that can produce a decent charge?

    Posted by Tim Daly

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    1. The production of 2 volts and 2 milliamps is based of the amount of ammonia produced in each fuel cell, but the idea to create a larger fuel cell with a larger amount of urea is a great idea. I imagine that based off an educated calculation, rocket scientists of all people would be able to create a fuel cell battery the size similar to those in electric cars, creating more efficient ships which could possibly lead to further space exploration.

      Posted by Thomas Flores

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  2. This is really interesting because I know from farming and ecology that urea is a big factor in the nitrogen cycle and in a small, enclosed, living space like a space shuttle where resource management is critical. And once they improve and perfect the recycling of urine, the applications could be amazing if large scale applied.

    Nicole Peterkin

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    1. The idea of using urea as fertilizer for small crops in space expedition could be potentially very beneficial. The only detraction from this is that the fertilizer is usually in solid form, so the production of it on board could be problematic. But if successful, astronauts would have a cheap, sustainable, and renewable fertilizer to create fresh food, which I'm sure would be to the delight of those on board the ship.

      Posted by Thomas Flores

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