From: Doug Jones <randome@lightspeed.net>
Newsgroups: sci.space.policy
Subject: Re: urine recycling
Date: Sat, 06 Feb 1999 22:55:12 -0800

Zebulon A Haradon wrote:

> Does NASA or the Russian space program use any kind of "urine
> recycling" to reclaim water from urine, or do they send up all
> the water they need? If they don't use it, why not, it sounds
> like it should be relatively easy to do (is it?)

There are several difficulties with recycling urine.  In addition to
salts, thre are volatile organic compounds which are difficult to
distill out because they have vapor pressures similar to water.  When
urea oxidizes it releases ammonia which is even harder to remove.

Various efforts have been made to recycle urine in lab experiments, but
none have flown.  They need significant amounts of reagents to take care
of the organics, and the resulting distillate is of poor quality.

Since urine is a small part of metabolic water (most is exhaled), it's
simpler to just dump or store it, or worst case use the nonpotable water
from urine processing for electolysis into H2 and O2 for stationkeeping
propellant.  Water inventories tend to rise anyway since food, aven
dehydrated, is basically poly(CH2O).  Condensate from the air is used on
Mir, but not for drinking water IIRC.

--
Doug Jones, Rocket Plumber
Rotary Rocket Company

From: jamesoberg@aol.com (JamesOberg)
Newsgroups: sci.space.policy
Subject: Re: urine recycling
Date: 7 Feb 1999 15:07:02 GMT

The Russians use cabin air distillate for drinking, and they do process urine
to produce water for electrolysis into oxygen -- waste hydrogen is vented
overboard, and the leftover brine is pumped into Progress vehicles, or
transported there manually in big plastic bags, for disposal.

See my book 'Pioneering Space', 1986, for a chapter on closed-loop life support
in space.