Planetary Protection Issues

Terraforming a planet would naturally have dramatic effects on the pre-existing environment of the planet. While we would engineer these changes for our benefit, they may be harmful to any life already there. It has been postulated that microbes may be living on Mars today, either dormant, or in subsurface reservoirs of water heated by geothermal energy

Planetary Protection measures were implemented in 1967 originally to protect Earth from any foreign microbes we might bring back from say, a Mars Sample Return Mission. However, they also exist to protect other planets from any terrestrial organisms we may introduce either by accident or design. Planetary spacecraft are sterilized to minimize the number of organisms they carry, for example.

A 1992 report by COMPLEX (the Comittee on Planetary and Lunar Exploration) provides several recommendations to the Space Sciences Board. Among them are:

• Adopt current molecular analysis methods to determine the bioburden on missions
• Landers must be sterilized at least at the level of the Viking missions to reduce terrestrial contamination of other planets
• Orbiters must be assembled in clean rooms, but need not be sterilized
• Several unpiloted missions shoud be sent well before any manned missions
• Martian sites must be studied to determine where best to look for life on Mars.
• NASA must inform the public about these policies
• NASA should get international agreement as to the planetary protection policies

Terraforming Mars goes against all policies of preventing terrestrial contamination. If it can be proven that there is not now any life on Mars, there will be few issues with such a development. However, if microbes are discovered, terraforming will have significant impact on them. It is unlikely that any such organisms would be killed by the changes we mean to introduce. All life as we know it (i.e. on Earth) can survive under the conditions we'd like to impose. The only exceptions are certain extremophiles which metabolize sulfur compounds at high temperatures near deep sea vents. Enviroments such as those are found nowhere on Mars (though they may be present under the Europan ocean. However, Earth life is well-adapted to living under Earth conditions and may outcompete Martian life on a terraformed planet. If Antarctica has been preserved against human settlement (scientific posts excluded), Mars surely should be kept as pristine as possible. Scientific expeditions and perhaps even bases could be established, but the extinction of indigenous life on a planet is probably too high a risk to warrant terraformation. Such policies, however, are best left to an international committee to decide, as recommended by COMPLEX.

These pages designed by James Roberts
Last updated:  05 May 2002

http://anquetil.colorado.edu/~jhr/terraform/protection-nf.html