Protecting the Solar System From Contamination 121
tcd004 writes "An article at PBS begins, 'Imagine this crazy scenario: A space vehicle we've sent to a distant planet to search for life touches down in an icy area. The heat from the spacecraft's internal power system warms the ice, and water forms below the landing gear of the craft. And on the landing gear is something found on every surface on planet Earth... bacteria. Lots of them. If those spore-forming bacteria found themselves in a moist environment with a temperature range they could tolerate, they might just make themselves at home and thrive and then, well... the extraterrestrial life that we'd been searching for might just turn out to be Earth life we introduced.' The article goes on to talk about NASA's efforts to prevent situations like this. It's a job for the Office of Planetary Protection. They give some examples, including the procedure for sterilizing the Curiosity Rover: 'Pieces of equipment that could tolerate high heat were subjected to temperatures of 230 to 295 degrees Fahrenheit for up to 144 hours. And surfaces were wiped down with alcohol and tested regularly.'"
Re:better to err on side of caution (Score:4, Insightful)
First you need to give Mars a magnetic field to shield it from the radiation given off by the Sun, which also strips off any atmosphere that accumulates too. It's also pretty good at killing things too.
Re:but rats still got every where (Score:5, Insightful)
I think the analogy stands. Consider the tardigrade, an animal composed of 40,000 or so cells (every adult has the exact same number of cells). They have been shown to survive freezing to near 0K, heating to over 130C, and the radiation and vacuum of space outside the ISS (or was it the Shuttle?).
The point is that for a given potential infestation, the bugs only have to succeed once. Sterilization measures have to be 100% successful every time. And they aren't, can't be and won't be. Even if we never actually put humans into space again, every vehicle will contribute it's little pile of DNA. Each halving of the number of impurities left on a surface increases the cost, difficulty and effort by an order of magnitude. (hmm - this is much like the 90% rule of software!)