Space Seeds Return to Earth

Seed pods from a commercial gardening experiment aboard the ISS are back on our planet. The far-out pods could hold the key to long-term habitation of space.

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July 25, 2001: When the space shuttle Atlantis returned to Earth this morning, it brought home some unusual cargo -- seed pods grown in space. They're the harvest of an 8-week-long commercial gardening experiment on board the International Space Station (ISS). Astronauts on the ISS have been tending a batch of fast-growing Arabidopsis plants (better known as "mustard weed") to discover whether plants can complete their entire seed-to-seed life cycle in a weightless environment.

Video from the experiment shows that seed pods were produced by the space-borne plants. But scientists aren't yet certain what's inside the pods.

Above: A top-down view of the ADVANCED ASTROCULTURETM plant growth chamber on the ISS, 28 days into the experiment. The leafy heads of the Arabidopsis plants are visible in the reddish light, which is a frequency (color) of light that plants can utilize for photosynthesis. Image courtesy NASA Marshall Space Flight Center.

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"We are waiting for retrieval of the payload to see whether or not seeds are indeed inside the seed pods," says Weijia Zhou, Principal Investigator for the ADVANCED ASTROCULTURE^TM plant growth chamber that harbored and nourished the seedlings on the ISS. "Personally, I have a very high confidence level that they will have seeds," he added.

Zhou is the Director of the Wisconsin Center for Space Automation and Robotics (WCSAR), a NASA Commercial Space Center that built the growth chamber. "This research is a joint endeavor between WCSAR and Space Explorers, Inc. (SEI)," explains Zhou. SEI is a private company specializing in the development of educational products for schools. Data from the ADVANCED ASTROCULTURE^TM experiment will allow SEI to complete an Internet-based multimedia program called Orbital Laboratory, which students and educators can use to study plant biology in classrooms.

If normal, healthy seeds were produced as Zhou suspects, the experiment will be a good sign that future astronauts can grow multiple generations of plants in space. Such self-perpetuating gardens will be a practical necessity for humans as they explore and colonize the solar system. Hardy space plants could provide fresh food, oxygen, and even clean water for explorers living for long stretches aboard orbiting outposts or on the Moon and Mars.

Left: An Arabidopsis plant with tiny seed pods at the top. The small size of the plant was part of the reason researchers chose it for the experiment aboard the ISS, where physical space is at a premium.

Now that the plants are back on Earth, scientists at WCSAR will analyze them to learn if growing in the weightless environment of free-fall had any ill effects

"Most importantly, we need to see how many seeds were produced," Zhou says. Comparing the fecundity of the space-grown plants to a control group grown under identical conditions on the ground will tell researchers whether the conditions of growth -- such as temperature, moisture, and fertilizer concentrations -- were indeed optimal.

"The second thing we need to do is conduct a final chemical analysis of the seeds to find out if there was a different phytochemistry involved," Zhou says. (Phytochemistry is a term for the chemical make-up of a plant.) If there is a difference, it would likely be caused by the weightless environment where the plants were gardened, he added.

Right: While the ADVANCED ASTROCULTURE Arabidopsis plants were flying in space, students grew control specimens on the ground for comparison. [more]

These seeds will be preserved for use in a similar experiment to be flown to the ISS by a shuttle flight currently scheduled for November 2001. Half of the seeds in that experiment will be from this space-grown batch, and the other half will be regular Earth-grown seeds. Comparing the plants and seeds produced in this follow-up experiment will tell scientists whether the conditions of space have any effect on subsequent generations of plants.

Eventually gardens could become a routine part of space travel. "NASA has announced a plan to sustain a long-term human presence in space," notes Zhou. What are those astronauts going to eat? "Are they going to eat all dehydrated food, or are they going to get some fresh salad crops?" he asks.

Salads and vegetables are not only good nutrition, but they could also offer an important psychological boost to diners who have spent a long time in space. Eating reconstituted foods from plastic bags is bound to grow tiresome eventually. Fresh lettuce or broccoli might be a welcome change -- even for kids.

Left: ISS Expedition Two astronaut Jim Voss tending to the plant-growth modules in the Unity lab module.

Plants in space won't only be a source of food -- they'll have other jobs to do as well, playing a critical role in cutting-edge life support systems.

On Earth, photosynthetic organisms like plants and algae provide a natural life support system for the planet's many life forms. Plants and algae use energy from light to split water molecules into hydrogen and oxygen. Then they combine the hydrogen with carbon dioxide to make sugars, which serve as food. Oxygen is released into the air as "waste." This serves as a perfect compliment to other life forms such as animals and fungi, which use the oxygen and respire carbon dioxide.

Taking a cue from nature, scientists at NASA's Johnson Space Center and Kennedy Space Center are pioneering next-generation "bioregenerative" life support systems, which use plants rather than machines to perform the chemistry of life support.

Above: By mimicking the cycles of nature, "bioregenerative" life support systems may someday provide food, oxygen, and water to spacefarers for long-term missions.

Not only do plants release precious oxygen, they can also help recycle drinking water. After some processing, nutrient-rich wastewater can be used to water and fertilize the plants. Much of the water absorbed by the roots will evaporate from the leaves as pure water vapor. Condensing this water vapor out of the air creates virtually pure, distilled water that can be used for drinking.

While elegant in theory, the fine details of such a system must be worked out before plants and people can live in a successful space-symbiosis. Learning to grow many generations of plants in space is an early step toward that goal.

Right: Research facilities like this one at NASA's Kennedy Space Center are working on the details of growing reliable space crops.

Many research teams at NASA and NASA-sponsored university projects are experimenting with plant growth for space missions, but Zhou's team is the only one at the moment that's actually growing plants in space from seed to seed.

"What WCSAR and industry are doing is rather unique," Zhou says. But researchers hope it will soon be common. Fast-growing plants that thrive from generation to generation in orbit will surely produce the seeds from which human exploration of space will spring.

Space Seeds Return to Earth July 25, 2001 presented by ThursdaysClassroom.com

Thursday's Classroom Corner

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These lessons and activities are based on the Science@NASA story
"Space Seeds Return to Earth."

• Discussion Questions: This activity will sow the seeds for a lively discussion about out-of-this-world gardening in your very own classroom. [lesson plan] [activity sheet]
• Far-out Fresh Foods: Can anything make kids covet fresh broccoli? Or yearn for lettuce straight from the garden? By comparing the taste of dried, reconstituted and fresh vegetables, your students will gain a new perspective on the joy of greens. [lesson plan] [activity sheet]
• The Color of Space Plants: What will farming be like on other worlds? Younger kids will enjoy coloring these alien gardens by Duane Hilton. [Astrofarmer] [Mars Corn] [Harvest Moon]

Use this button to download the story with lessons and activities in printer-friendly Adobe PDF format:

Wisconsin Center for Space Automation and Robotics (WCSAR) at the University of Wisconsin-Madison is a Commercial Space Center (CSC), managed by the Space Product Development (SPD) Office at NASA's Marshall Space Flight Center. WCSAR's mission is to assist commercial companies to develop advanced commercial products and technologies derived from space-based plant biotech research. The ADVANCED ASTROCULTURETM experiment was sponsored by Space Explorers Inc. (SEI) -- a private company specialized in the development of commercial educational products.

ADVANCED ASTROCULTURETM --The objectives of this experiment are (1) to validate the plant life support technologies/systems developed by WCSAR for long term operation in space; 2) to determine whether Arabidopsis can complete its seed-to-seed life cycle in microgravity; and (3) to compare seeds produced in space with seeds harvested on Earth.

Teaming Up on Space Plants -- Science@NASA Story Students, scientists and astronauts are joining forces to learn more about how plants grow on the International Space Station.

Leafy Green Astronauts -- Science@NASA Story NASA scientists are learning how to grow plants in space. Such far-out crops will eventually take their place alongside people, microbes and machines in self-contained habitats for astronauts.

See also, NASA's Space Commercialization and Space Product Development web sites.

Space Explorers, Inc. -- a commercial company based in Green Bay, Wisconsin, that is developing curriculum for schools.

Space Farming -- a distance learning module from Johnson Space Center

Advanced Life Support definition -- explains why future life support systems for space exploration -- and possibly colonization! -- will use plants for food, oxygen generation, and possibly water purification. From NASA Kennedy Space Center.

NASA plant physiology research -- information about efforts to learn how to grow food crops in space

The role of Arabidopsis in plant science research -- information on Arabidopsis and why it has become the "model organism" for plant science research

Arabidopsis Information Resource -- access to a wide range of information on Arabidopsis, including genomic data