ECOLOGY AND THERMAL INACTIVATION OF MICROBES IN AND ON INTERPLANETARY SPACE VEHICLE COMPONENTS Thirty-ninth Quarterly Report of Progress

摘要

The dry-heat terminal sterilization cycle for the Viking lander was tentatively set for a total of 60 hr. This provides 112 C exposure for 30 hr with 1.2 ug of water per ml of head-space air 25％ RH at 0 C at STP). These parameters were based on experimental findings by several National Aeronautics and Space Administration laboratories' studies of dry-heat inicti-vation studies of Bacillus subtilis var. niger spores. Re¬cent studies have shown that naturally-occurring spores found around assembly and industrial manufacturing areas of space ve¬hicles exhibited higher dry-heat, resistance than Bacillus sub¬tilis var. niger (Bond, et al., 1970;1973). Studies from the Kennedy Space Center Teflon ribbon experiments showed recovery of spores after the terminal sterilization cycle at 113 C and 0.134％ RH (25％ RH at 0 C STP).