Viking Pre-Sterilization

Viking Post-Sterilization

Other Approaches

MER Landers/ Rovers

No Life-Detection Instruments

COSPAR Category IVa


The hardware design was compatible with swab assays and alcohol wipe cleaning. Hardware that could not tolerate alcohol (honeycomb structures, airbags, parachutes, solar arrays) was sterilized using dry heat. Heating was done at 110°C for 50 h and 125°C for 5 h for some components. Tubing elements were precision cleaned with an acid wash, Freon degreasing, and other cleaning methods. Enclosed electronic components were isolated from the Mars environment by high-efficiency particulate air (HEPA) filters.

The spacecraft was assembled in a class-100,000 clean room. Hardware that was dry heat sterilized was double bagged for protection. Elements that were not cleaned were covered.e


Early planning allowed for more extensive use of dry heat.

aClass-100,000 clean rooms: rooms with air quality control to a maximum of 100,000 particles of 0.5 µm in diameter per cubic foot of air.

bNRC, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000, p. 5.

cJack Barengoltz. Microbial cleanliness of the Mars Pathfinder spacecraft. Pp. 242-248 in Proceedings of 43rd Annual Technical Meeting Contamination Control. Institute of Environmental Sciences, 1997.

dAndrew Spry, Open University, presentation to the NRC Committee on Preventing the Forward Contamination of Mars, February 27, 2004.

eLaura Newlin, Planetary Protection Lead for the MER Missions, Jet Propulsion Laboratory, discussion with the NRC Committee on Preventing the Forward Contamination of Mars, February 26, 2004; “Mars Exploration Rover Spacecraft Undergo Biological Testing and Cleaning Prior to June Launches,” KSC Release No. 37-03, May 23, 2003, NASA John F. Kennedy Space Center.

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