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08/09/94

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Growing pains: Stanford student helped develop shuttle experiment

STANFORD -- A Stanford graduate will see eight years of work go up atop a pillar of fire on Thursday, Aug. 18, when the space shuttle Endeavor carries into orbit an experiment he helped devise.

The experiment examines the germination of tomato, turnip and cucumber seeds in microgravity.

Theodore Johnson of Chicago, a 1993 graduate in mechanical engineering, started his space quest almost eight years ago as a high school student, while studying with scientist Konrad Dannenberg at Space Camp in Huntsville, Ala.

With Dannenberg's encouragement, Johnson submitted a proposal for an experiment testing the effects of microgravity on the germination and early growth of seeds. Dannenberg teamed Johnson with three other camp students who had submitted similar proposals.

After working with several different varieties of seeds and completing multiple tests on their growth in spacelike conditions, the group settled on a mixture of tomato, turnip and cucumber seeds, because of their ability to germinate and grow rapidly in total darkness.

Aboard the Endeavor, the seeds will be placed between sheets of filter paper in a growth chamber, and provided a constant supply of water by an electrical pump. A computer-controlled battery will maintain the power supply. The lightproof growth chamber will be hermetically sealed and placed in the shuttle's payload bay inside a container with three other experiments.

The student team plans to examine how microgravity affects the physical and chemical functions of the cell, such as the direction of root and stem growth. Although this will not be the first experiment of its kind, Johnson hopes that his data will provide confirmation or refutation of previous tests.

A similar experiment conducted by other scientists failed when seeds froze in the shuttle's exposed payload bay. Johnson contributed to his group's experiment by refining temperature-control mechanisms to protect against the payload bay's subzero temperatures.

During Johnson's junior year at Stanford, he received a $500 Undergraduate Research Opportunities grant to support the development of the heating system. Johnson analyzed heat transfer, convection and insulation mechanisms, finally coming up with a device that utilizes space-age insulation material and a tiny heating strip. The 1-inch square heating strip, with the thickness of two sheets of aluminum foil, can maintain a constant temperature of 22 degrees Celsius in the growth chamber.

Johnson said he received invaluable guidance from his faculty sponsor, mechanical engineering Professor Robert Moffat.

Johnson, who is now a hardware design engineer with Hewlett- Packard in Massachusetts, said he was excited about the experiment, and was "confident that the seeds will grow."

The other students who worked on the project are: David Brain, a senior in astrophysics and math at Rice University; Lynn Klein, a recent graduate in mechanical engineering from Washington University in St. Louis; and Mark McKibben, a senior in biology at Ohio University. Dwight Brewer, a junior-high student in Alabama, recently joined the team and, according to Johnson, has been a "rejuvenating factor" for the other researchers.

-wec-

This release was written by Wesley Cole, a science writing intern at the Stanford News Service.

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