Exhaling For
Exploration: Scientists Test Lunar Breathing System
(7 May 2008) Imagine yourself
hip-to-hip, shoulder-to-shoulder, inside a room the size of a walk-in closet
for eight hours with five people you just met.
Does that make
you sweat? Or maybe make your breathing a little more animated?
For
three weeks, 23 volunteers dedicated time to do just that -- sweat and breathe
-- inside a test chamber so NASA scientists at Johnson Space Center in Houston
could measure the amount of moisture and carbon dioxide absorbed by a new
system being developed for future space vehicles. The system is designed to
control carbon dioxide and humidity inside a crew capsule to make air
breathable and living space more comfortable.
The tests, which took
place from April 14 to May 1, are some of the first to use human subjects in
support of NASA's Orion crew capsule, Altair lunar lander and lunar
rovers.
"We're moving from paper studies to tests with hardware that
will evolve and become part of the spacecraft that will fly back to the moon,"
said test volunteer and NASA engineer Evan Thomas at Johnson.
Known as
the Carbon dioxide and Moisture Removal Amine Swing-bed, or CAMRAS, the
Exploration Life Support project within NASA's Exploration Technology
Development Program is developing the new system. The program is investigating
technologies that will help sustain life on exploration vehicles and reduce the
dependence on resupply from Earth.
"Our goal for CAMRAS is to develop a
simple, regenerative, lightweight device that will work for both the Orion crew
capsule and the Altair lunar lander," said lead researcher Jeff
Sweterlitsch.
Testing on the device began more than a year ago with
machines used to create humidity and carbon dioxide in the test chamber. The
tests proved the system worked well, but the machines could not generate the
wide variety of metabolic loads -- amounts of energy the body's chemical
reactions produce to maintain life -- that humans create.
This series of
tests put volunteers inside a test chamber scaled to be the size of the Orion
crew capsule, about 570 cubic feet. The volunteers, who were selected and
grouped to replicate a typical crew, were asked to sleep, eat and exercise
during test sessions that lasted from a few hours to overnight.
"The air
smelled a little artificial, like on a plane, and it was a little crowded,"
said Aaron Hetherington, one of the volunteers and a director for the test.
"But the air was fine; the temperature comfortable. My biggest observation is
that it was unremarkable, which is good because that means the hardware was
working."
Two additional phases of testing on CAMRAS are
planned.
The CAMRAS absorption beds are regenerated by the vacuum of
space, and processing the carbon dioxide and moisture requires little energy.
CAMRAS uses an organic compound known as amine that absorbs the carbon dioxide
and water vapour from the cabin's atmosphere. The system then vents the two
waste products overboard, and the vacuum of space regenerates the amine to work
again.
The Exploration Life Support project also is developing
technologies that will recover oxygen and water vapour, recycle spacecraft
wastewater into drinking water and recover usable resources from
wastes.
(source: NASA)
