Using its Advanced Astroculture (ADVASC) plant growth chamber, the College of Engineering’s Wisconsin Center for Space Automation and Robotics (WCSAR) recently completed the first commercially sponsored plant growth experiment on board the International Space Station (ISS). After eight weeks of gardening in space, 91 fast growing Arabidopsis plants (better known as mustard weed) produced a harvest of seed pods confirming that Arabidopsis can complete an entire seed-to-seed life cycle in a weightless environment. WCSAR scientists and engineers monitored and controlled the experiment from their own “mission control” located in Room 101 Mechanical Engineering Building.
“The ADVASC has successfully demonstrated the capabilities of providing precisely controlled environment conditions including temperature, humidity, light, fluid nutrient, CO2 concentration, and ethylene degradation for plants to grow,” says WCSAR Director Weijia Zhou.
WCSAR grew the plants for Space Explorers, Inc. (SEI). The Green Bay-based private company develops commercial, educational products. SEI will use the science and engineering data gathered to develop an internet-based multimedia software and curriculum called Orbital Laboratory. The software will allow students and educators to compare ground plant experiments with space plant experiments, to study microgravity effects on plant growth, and to create a virtual environment for students to design, conduct and analyze the space experiment on Earth.
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.
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, he says it would likely be caused by the weightless environment where the plants were gardened.
The 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.
WCSAR is currently developing a second ADVASC unit, a $1.25M payload funded by NASA, which will be used, in conjunction with the first ADVASC, to continuously support commercial research on-board the ISS in the future.
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