Plant Growth Unit (PGU)

For 15 years, the Plant Growth Unit (PGU) was a highly successful platform for shuttle-era astrobotany experiments (1982-97). The PGU was the first American platform to run regular flight experiments on biological life support systems, and its experiments examined seedling growth, lignification, and reproduction. The PGU was designed and built by Lockheed Missiles and Space Company for the Ames Research Center, and was eventually upgraded into its successor, the Plant Growth Facility (PGF).

Chamber Components:

  • One PGU holds six removable, airtight Plant Growth Chambers (PGCs)
  • Growth area holds seedlings (seeds sandwiched between filter paper-like material)
  • Lighting System (three 15 W [50 to 75 umol/m2s] fluorescent lamps on a timer)
  • Temperature control (fans and heater strips)
  • Designed to lower (but not control) CO2 concentration


  • Review and analysis of plant growth chambers and greenhouse modules for space (link)
  • Hardware Information: Plant Growth Unit (PGU) (link)
  • Plant Growth Facility: A Recent Design Provides Improved Capabilities for Use in the Shuttle Middeck (link)
  • A Researcher’s Guide to the International Space Station: Plant Science (link)