Importance of temperature control for HEFLEX, a biological experiment for Spacelab 1

HEFLEX is an experiment in plant gravitational physiology now being developed for the Spacelab 1 Mission. Its object is to measure kinetic properties of plant nutation in a very low g environment. HEFLEX is designed to be scientifically compatible with restrictions imposed by engineering considerations. Among those restrictions one of the more important but one not necessarily well appreciated by mission engineers is the specification for spacelab air temperature. Development of the HEFLEX space experiment has been seriously complicated and the flight hardware significantly increased in cost as a result of the burden of insuring adequate temperature control being shifted from the spacelab module design to the biological experiment itself. The question is raised: Is this the most economical method of implementing biological research in space?