Under the NASA Space Biology Initiative (SBI), a CELSS Test Facility (CTF) is being planned for installation on Space Station Freedom. The CTF will be used to study the productivity of typical CELSS higher plant crops under the micro-gravity conditions of the Space Station Freedom (SSF). Such science studies will be supported under the CELSS Space Research Project (CSRP). The CTF will be used to evaluate fundamental issues of crop productivity, such as the production rates of O2, food and transpired water, and CO2 uptake. A series of precursor tests that are essential to the development of the CTF will be flown on Space Shuttle flights. The tests will be used to validate and qualify technology concepts, and to answer specific questions regarding seed germination, root/shoot orientation, water condensation and recycling, nutrient delivery and liquid/gas phase interactions.