Plant Growth in Microgravity

The Plant Generic Bioprocessing Apparatus (PGBA) was a plant growth chamber developed by BioServe to investigate plant physiology in microgravity. With its first mission in 1996, PGBA supported plant experiments on three separate Space Shuttle missions (STS-77, STS-83, and STS-94) and also operated onboard the ISS for a short stint in 2002.

PGBA required a double middeck locker form-factor to fit the necessary hardware which included a central Plant Growth Chamber (PGC). The PGC included a complex system to deliver nutrients to the root matrix mechanical structure. The PGC was supported by the following subsystems:

  • Lighting system to provide energy for plant photosynthesis
  • Carbon dioxide control system to keep CO2 low
  • Humidity control system to remove excess transpired water and recycle it back to the plant roots
  • Ethylene removal system to limit accumulation of toxic plant-growth byproducts
  • Dual video cameras to capture plant growth over time
  • Thermal control system to maintain the PGC at a constant temperature
  • Computer system to autonomously control PGBA and communicate to the Space Shuttle
  • LCD touch screen for crew interface