[40] 

LOW PRESSURE STUDY FOR THE DEVELOPMENT OF A MARS GREENHOUSE.  L.M. Gravatt¹, P.A. Fowler², V.Y. Rygalov³, and R.M. Wheeler⁴.   ¹University of Minnesota, Minneapolis;  ²Dynamac Corporation, Kennedy Space Center, FL;  ³University of Florida, Gainesville; ⁴NASA, Kennedy Space Center, FL.

     The goal of this study was to design, develop, and test a low pressure, closed environment that was conducive to plant growth.  An environment was designed and built in a way that allowed for the control of temperature, pressure, and relative humidity in the system.  The methodology of this study consisted of determining the controllable parameters, designing the environment, constructing the environment, and testing the system.  System consisted of three bell jars placed into two Percival Environment chambers.  Each bell jar had a cooling coil used to cool the air and collect condensation.  The condensation was then collected and measured in a graduated cylinder.

     The results showed that relative humidity is not dependent on total pressure, but it is dependent on the temperatures of the jar and the cooling coil.  As for the water cycle, data showed that evaporation rates did not give any significant results.  However, it was observed that more water was collected in the graduated cylinder at lower pressures.  From this study, it was concluded that an artificial environment can be created such that temperature, pressure, and relative humidity are controlled and a water cycle is produced.  In addition, it can be concluded that it is only necessary to control two temperatures (bell jar temperature and coil temperature) in order to control the system.

     (Supported by NASA, SLSTP)