Levin says this is especially important because Viking was sterilized to prevent contaminating Mars with hitchhiking terrestrial microorganisms. Since then, none of the many NASA and ESA Mars landers, including Curiosity, have been sterilized. Thus, any new findings of life might be questioned as to whether the life was indigenous to Mars or came from Earth.
Levin stresses, "The Viking LR life detection data are the only data that will ever be available from a pristine Mars. They are priceless, and should be thoroughly studied."
Spacecraft (including orbiters) without biological experiments should be subject to at least Viking-level pre-sterilization procedures – such as clean-room assembly and cleaning of all components – for bioload reduction, but such spacecraft need not be sterilized.
Even if Curiosity's microscope does spy a microbe scurrying across a sample, or if its scanners detect what might be biomolecules, such finds might not be conclusive evidence of life on Mars, "because we'd have to ask whether or not we brought them to Mars," Conrad said. "We have cleaned the spacecraft very carefully, but you'd have to ask whether anything we see that might be a sign of life was a contaminant, and we'd have a high burden of proof to overcome."
Originally posted by Phage
The worry is not about contaminating Mars. The worry is about interfering with experiments.
Curiosity was constructed in clean room conditions. It meets the established recommendations for "planetary protection" and the requirements of its science mission.
Spacecraft (including orbiters) without biological experiments should be subject to at least Viking-level pre-sterilization procedures – such as clean-room assembly and cleaning of all components – for bioload reduction, but such spacecraft need not be sterilized.
planetaryprotection.nasa.gov...
mepag.jpl.nasa.gov...
It should be known that Levin has been carrying a large chip on his shoulder over his disputed claims about the findings of the Viking mission.
edit on 11/30/2011 by Phage because: (no reason given)
They probably just realized the ionizing radiation in space thoroughly kills everything.
The Deep Sleep
The Surveyor probes were the first U.S. spacecraft to land safely on the Moon. In November, 1969, the Surveyor 3 spacecraft's microorganisms were recovered from inside its camera that was brought back to Earth under sterile conditions by the Apollo 12 crew.
The 50-100 organisms survived launch, space vacuum, 3 years of radiation exposure, deep-freeze at an average temperature of only 20 degrees above absolute zero, and no nutrient, water or energy source. (The United States landed 5 Surveyors on the Moon; Surveyor 3 was the only one of the Surveyors visited by any of the six Apollo landings. No other life forms were found in soil samples retrieved by the Apollo missions or by two Soviet unmanned sampling missions, although amino acids - not necessarily of biological origin - were found in soil retrieved by the Apollo astronauts.)
How this remarkable feat was accomplished only by Strep. bacteria remains speculative, but it does recall that even our present Earth does not always look as environmentally friendly as it might have 4 billion years ago when bacteria first appeared on this planet.
Just as it would have killed the Apollo astronauts had they ever ventured away from low Earth orbit.
