Controlled Ecological Life Support Systeim 



Little information exists on the reliability of bioregenerative systems or higher plant 

 performance in a closed system. A series of ground-based, integrated CELSS 

 experimental and test systems will be needed to evaluate these issues prior to 

 design of a spaceworthy system. 



Tlie Soviet Experience 



The Soviets have had a long history of life sciences experiments evaluating the 

 growth of several species of higher plants and microorganisms in space. The 

 experiments include both short-term and long-term (>200 days) studies in space 

 and in combination with ground-based activities involving hermetically sealed 

 Bioregenerative Life Support Systems. The Soviets recognize the need for biore- 

 generative systems to support long-term space travel, and they have conducted 

 many tests of manned-closed systems using both higher plants and algae in their 

 BIOS programs. A 1-year isolation study with three persons in a hermetically 

 sealed chamber has been completed, along with several shorter term (30 to 50 

 days) studies in which man-algae and man-higher plant systems were evaluated. 



Current European and Japanese Experience 



European industrial groups, including Dornier and MBB/ERNO, are conducting 

 CELSS research under sponsorship of the European Space Agency and the 

 German Research and Development Institute for Air and Space Travel. Progress is 

 being made with algal systems and the beginnings of higher plant systems. 



CELSS efforts in Japan have been embraced by a community of scientists 

 representing a number of disciplines. Current projects include algal growth in 

 bioreactors, fish-culturing technologies, waste processing, higher plant growth, and 

 related technologies. Although no long-term CELSS program is defined at present, 

 the level of CELSS-related research is expected to increase as the National Space 

 Development Agency of Japan (NASDA) module is prepared for the Space Station 

 era. 



Future Directions 



How plants perform in space is the "make or break" question for the CELSS 

 Program. Microgravity may cause stress to plants and substantially reduce their 

 productivity, especially when plants must be grown from seed, to seed, to seed in 

 a functioning CELSS. The Breadboard and other CELSS research projects will 

 show what performance can be obtained from plants on the ground, but plant 

 experiments must be conducted in space to test the conclusions of ground-based 

 research. 



CELSS flight experiments will require relatively ambitious missions. Even for 

 small, fast-growing plants, the minimum duration of a complete growth cycle is 

 about 45 days. Thus, CELSS experiments will require relatively lengthy stays in 

 space. In addition, CELSS flight experiments will require onboard controls at 1 g 



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