Steve Roy
Marshall Space Flight Center, Huntsville, Ala.
(Phone: 256/544-0034)
Dolores Beasley
Headquarters, Washington
(Phone: 202/358-1753)
In a remote, hostile, totally alien environment, every
life-sustaining resource is precious. In space, other than
air, none is more precious than water.
Improving the careful use of that critical resource is the
goal of the Vapor Compression Distillation Flight
Experiment, which is undergoing tests during the STS-107
Space Shuttle mission launched January 16.
The experiment, managed by NASA's Marshall Space Flight
Center in Huntsville, Ala., is a full-scale demonstration of
technology being developed to convert crewmember urine and
wastewater aboard the International Space Station into clean
water for drinking, cooking and hygiene. Based on results of
the experiment, an operational urine processor could be
installed aboard the Station in the future, thus reducing
the amount of water that must be re-supplied from Earth.
"We operated successfully on Saturday, Sunday and Monday
(Jan.18-20)" said Cindy Hutchens, manager of the Vapor
Compression Distillation Flight Experiment. "Our data look
very similar to that on the ground, so we feel very
confident about our hardware. Mission Specialist Laurel
Clark described our processed water samples as clear, which
is very good. On Sunday, we did a test to see how it would
start up if it lost power, and that appears to be
successful. We're looking forward to getting back our
samples and the recorded data for analysis," she said.
Aboard the Space Station, each of the three crewmembers is
allocated just 4.4 gallons of water per day. By comparison,
the average American uses 60 gallons per day on Earth. Not
only is it costly to carry water into space aboard the Space
Shuttle and Russian Progress spacecraft, but also cargo
space is already much in demand for carrying up food,
clothing, equipment and scientific experiments. NASA is
working to collect and recycle as much water as possible to
save space and reduce costs.
"The water recovery system on the Space Station will be
similar to a water treatment plant on Earth. The process has
to be different on the Station in order to operate in the
weightlessness of space and to fit in the area of about two
phone booths," Hutchens said.
The experiment is part of a NASA effort to reduce technical
risk between the design of flight hardware and actual
installation aboard the Space Station, Hutchens said. The
vapor compression distillation process mechanically mimics
Earth's natural process of evaporation. Instead of heating
water with the power of the sun, however, these systems boil
wastewater to produce and collect water vapor that is 97
percent free of minerals, chemicals and microbes.
The experiment is designed to verify the recycling concept
in microgravity, the low-gravity environment created as a
spacecraft orbits the Earth. For the experiment, de-ionized
water containing some salts was used instead of urine.
The experiment occupies a refrigerator-sized rack in the
SPACE HAB module in the Shuttle payload bay for the STS-107
mission. Experiments will test the system under a series of
normal and abnormal operating scenarios. The Shuttle crew
activated the experiment, but it is primarily automated. The
experiment team monitors operations and receives data in a
control room at NASA's Johnson Space Center in Houston.
Part of the Station's water processing system was tested on
a KC-135 aircraft in 2002 that simulates microgravity
conditions.
"When this technology is installed aboard the Space Station,
it will be able to process about 4,400 pounds (2,000 kg) of
waste water annually to support the crew, and decrease the
water requirements on resupply missions," Hutchens said.
"Beyond that, further human exploration of space will
require water recycling technology. And it may even have
applications on Earth, where many people don't have ready
access to a clean water supply," she said.
For more information about the STS-107 mission:
www.spaceflight.nasa.gov
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