The Design of a Mechanized Seed Sowing System for Space Flight Application

Improvements in plant illumination, irrigation, and thermal control systems have led to significant progress in the cultivation capability of space flight plant growth facilities. An area that has received little attention, however, is the on-orbit ability to sow and initiate the germination of seed within these facilities. In addition to the need for adequate levels of water and gas exchange, seeds must be maintained in a specific physical orientation due to the absence of a gravity vector to ensure that emerging root and shoot material is directed in an appropriate orientation. An approach involving the immobilization of seed in a matrix material is being evaluated as a means of not only providing appropriate germination conditions but also the efficient physical manipulation of seed. The design of a mechanized sowing system, based on the manipulation of matrix immobilized seed is presented in this paper. Although the system was designed to operate autonomously in the Plant Growth Unit used aboard the Space Shuttle it can be adapted for long-term plant growth studies on the International Space Station.