Optimization of Root Zone Substrates for reduced Gravity Experiments

The ORZS plant module became the first space-based soil physics experiment when it launched aboard the ISS Progress 25 cargo spacecraft May 2007. NASA funded the development of the new hardware, which was designed and built by students. ORZS represents more than fifteen years of collaborative efforts between SDL, USU, and the Russian Space Agency.

The ORZS program objective was to optimize the plant growth rooting environment. During the ORZS experiments, SDL measured the root gas exchange through plant growth substrates at varying water content levels in microgravity.

Understanding plant behavior in microgravity is a significant factor in life support applications for NASA programs that will use plants to help solve the isolation, nutrition, and resource revitalization problems of long-term spaceflight. Analysis of the data collected indicates a significant difference in oxygen diffusion in smaller substrates under microgravity, with a smaller change evident in the mixed size substrates.