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Ensuring Long-Term Environmental Stability of Rodent Food Substrates within an Autonomous Life Support Module.   T.R.F. Fulford-Jones1, N. Steber1, H.B. Laird2 and D.H. Blustein3  1MIT Department of Aeronautics and Astronautics, 2MIT Department of Mechanical Engineering, 3Kalamazoo College, Michigan.

   The Mars Gravity Biosatellite, an international student-led program, will provide an artificial gravity testbed to study mammalian adaptation and development in partial gravity. The 5-week mission profile specifies a launch of fifteen female mice and utilizes both rotational and non-rotational time-delayed ground controls.

   Mars Gravity researchers have evaluated various mouse-approved food substrates for use during the mission. We have selected NASA’s Type I rodent food bars and have explored measures to extend the in-cage life of the diet such that it remains environmentally stable for a full thirty-five days or more. Our primary goal is to ensure that food bars remain free of mold and excessive bacterial contamination. A secondary priority is the minimization of dehydration-induced crumbling that could negatively impact performance of our custom underfloor waste collection and urinalysis systems.

   Wax coatings were identified as a means of retarding fungal growth and promoting water retention. We describe the performance of wax-coated and wax-free food bars during and after mission-length exposure, including an assessment of mouse health in terms of behavior and body mass. We present a profile of bacterial and fungal growth on and around the food substrates during the five-week testing period. We verify the performance of NASA-certified rodent-safe epoxy EP21LV when subjected to launch-like vibration and loading.

(Supported in part by NASA: SBIR Phase II Contract NNA05CP01C)