http://agnews.tamu.edu/dailynews/sto...T/Oct0506a.htm

Galaxy Gardening More Than Hobby for Future Moon, Mars Residents
Texas A&M University Agriculture Program
October 5, 2006

Writer: Kathleen Phillips,
Contact: Dr. Fred Davies,
Dr. Ron Lacey, 979-845-3967
Dr. Chuan He,

COLLEGE STATION - Long periods of total darkness and poor soil needn't
stop an avid gardener - at least not one who's willing to go out of
this
world to grow plants.

Lush lettuce is growing by galactic measure in cylinders designed by
Texas Agricultural Experiment Station researchers to mimic conditions
on
the moon and Mars.

"We're to the point now that we are confident with the systems we have
developed, though it may not ultimately look like this (lab model),"
said Dr. Fred Davies, Texas Agricultural Experiment Station
horticulturist.

The research, part of the National Air and Space Administration's
"Salad
Bowl" project, is unique in that university-based scientists are tasked
with finding a way to produce food in spatial conditions unparalleled
on
Earth.

Two certainties make this work important, the researchers believe:
Humans will continue to explore uncharted expanses of the universe, and
where humans go, food is a must.

"Exploration is part of our blood. Ultimately, we will start to inhabit
on lunar and Martian surfaces in the near future," Davies said.

For now, food is transported in shuttles in quantities to last a space
trip. Food also is taken to the International Space Station for the
three people who work there in six-month stints.

Astronaut fare has gone from "bite-sized foods suitable for eating with
one's fingers, and pureed foods, squeezed directly into the mouth from
flexible metal toothpaste-type tubes" to some 200 different menu
selections now including fresh tortillas and chicken fajita meat served
on more appealing food trays, according to NASA food nutritionists.

But ultimately, for people to live in space for longer periods,
self-sustaining food production would be vital, Davies noted.

Enter agriculture. The age-old profession is much on the minds of space
exploration scientists.

Davies said green produce in space has both nutritional and
psychological benefits. While leafy lettuce may provide humans with
essential nutrients such as vitamin A, it also provides a welcomed
fresh
texture for astronauts who quickly get their fill of reconstituted
food.

"A part that is important is the psychology of eating something that is
green, smells like something you are used to on Earth, that has some
texture to it and some freshness," Davies said.

Developing equipment to hurl humans into space has been less a
challenge
for engineers than finding ways to grow food. Mainly, all the earthly
conditions that make plants thrive either don't exist or are vastly
different in space.

The moon, for example, has no atmospheric pressure (vital for the
development of clouds and rainfall) and only one-sixth the gravity of
Earth. Its days, or period of light, last the equivalent of about a
month on Earth and are followed by the equivalent of two weeks of
darkness, Davies pointed out. And it has no carbon, which is essential
for photosynthesis.

Mars, on the other hand, has an atmosphere that is about 95 percent
carbon dioxide and an atmospheric pressure one-hundredth that of
Earth's. And while a Martian day is a little longer than earth's
24-hour
period, there is less available light for plant growth, the researcher
noted.

To figure out how to grow plants in space, scientists first had to toss
out what is known about plant production. They also had to design,
build
and operate growing chambers to work under space-like conditions. That
meant developing chambers that would work in low pressure and provide
plants with what's needed to photosynthesize, or grow and yield
adequate
quantities of food.

Thus far, their research has shown that the plants are doing better in
the low-pressure conditions.

"The advantage to low pressure means we have to have less materials
which means less cost," said Dr. Ron Lacey, Experiment Station
agricultural engineer. "But to create a system for plants to grow in
low
pressure is very challenging."

Lacey said previous research on such systems had numerous issues with
leakage - perhaps leaking the whole volume of air in a day.

"But we were able to create a very tight system that only leak about
1.5
percent of its volume per day or less," Lacey said, "and we see some
very interesting things going on (with plant growth)."

"We have found that the plants grow better in the low pressure, and
also
that the gas ethylene has a big effect on plant growth," said Dr. Chuan
He, Experiment Station researcher who plants, harvests and analyzes the
lettuce for quality. Plants under low pressure produce less ethylene
and
use-up less carbohydrates at night (lower dark-period respiration),
which produces larger heads of lettuce.

He, who said tending plants on Mars is his wished-for occupation, has
sampled the product of his labors.

"The lettuce actually tastes quite good," He said.

Davies noted that plants also are useful for producing oxygen and
reducing carbon dioxide, both important factors for humans.

"It may be that these plants are grown below ground in special growth
chambers on Mars and the moon," Davies said. "They are looking at ways
to be able to catch and store light on the moon and then be able to use
that light later on."

More information about the project is available at
http://aggie-horticulture.tamu.edu/f...arch/nasa.html .

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