Bio-regenerative Life Support

With a permanent lunar base, it is essential to keep resupply flights to a minimum. One of the best ways to reduce resupply needs is to have a closed-loop bioregerative life support system. This NASA press release is of particular interest for keeping life-support resupply costs low.

Michael Braukus
Headquarters, Washington, DC        August 28, 1995
(Phone:  202/358-1979)

Lisa Malone
Kennedy Space Center, FL
(Phone:  407/867-2468)


RELEASE:  95-145

STUDY SHOWS FEASIBILITY OF PLANT-BASED LIFE SUPPORT SYSTEMS

    The science fiction concept of plants providing a complete
life support system for the crews of lunar and deep-space
missions came a step closer to reality with the successful
completion of a NASA life sciences experiment that studied
potato production in a self-contained environment.

    "We have demonstrated that a bioregenerative life support
system really can support humans in an enclosed environment
over a long period of time,'' said Kennedy Space Center (KSC)
plant physiologist Dr. Gary Stutte.  "Our long-range goal is to
prove that a plant-based life support system is as reliable as
the mechanical systems found in today's spacecraft."

    KSC scientists conducted a successful 418-day experiment in
the Biomass Production Chamber of the Controlled Environment
Life Support System.  The experiment investigated how well a
biogenerative life support system can perform on a continuous
basis over an extended period of time.  This experiment was the
longest test of a major component of a bioregenerative life
support system ever completed.

    During the experiment, the potato plants produced enough
oxygen to support one crew member on a continuous basis, while
also removing excess carbon dioxide from the atmosphere, Stutte
said.  In addition, the potato crops produced enough food to
supply 55 percent of the caloric needs of an astronaut, along
with enough purified water for a total of four crew members.  A
larger chamber could be used to provide all the consumables for
the crew for as long as a mission might last, Stutte said.

    "The major advantage of the bioregenerative life support
system is that it does not need to be resupplied with food,
water and air, nor does it require expendable water or air
filtration systems as present-day mechanical spacecraft life
support systems do," said Dr. Bill Knott, chief scientist of
Biological Programs for the NASA/KSC Biomedical Operations
Office.  Instead, the current system recycles plant waste and
nutrients.  This recycled material sustains the plant crops,
which in turn produce the oxygen, water and food that the crew
would need for an indefinite period of time.

    Once the analyses of the KSC experiments are complete, they
will be provided to NASA's Johnson Space Center (JSC) Houston,
Knott said.  JSC research personnel will then use this data to
conduct research on the effectiveness of bioregenerative life
support systems with human subjects.

    "We have been supplying this kind of information since we
first began growing crops at KSC in 1987," Knott said.  "Some
of our data was used in preparing a recent JSC experiment where
a British chemist was supplied with all of his oxygen and
carbon dioxide removal requirements in a sealed chamber for 15
days by a crop of 30,000 wheat plants."

    Because of the success KSC has had with potatoes, this crop
will make up 75 percent of the food for the next bioregenerative
life support system experiment, Stutte said.  Wheat will make up
the remaining 25 percent of the crop during the two-year study
that will begin in January 1996.  "We feel that a mixed crop is
needed to optimize system production," Stutte said. "Potatoes
provide the highest yield, but wheat is more tolerant to longer
light cycles that might be used in the chamber."

    The planned longer studies also will provide more data on
the ability of the bioregenerative life support systems to
operate over an expected three-year mission to Mars.  "We feel
that we can keep this system going indefinitely," Knott summed
up. "There is no reason to believe we can't."