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Future Astronauts Must Deal With Toxic Chemicals In Martian Soil
Thorfinn.au sends this quote from Space.com:
"The pervading carpet of perchlorate chemicals found on Mars may boost the chances that microbial life exists on the Red Planet — but perchlorates are also perilous to the health of future crews destined to explore that way-off world. Perchlorates are reactive chemicals first detected in arctic Martian soil by NASA's Phoenix lander that plopped down on Mars over five years ago in May 2008. It is likely both of NASA's Viking Mars landers in 1976 measured signatures of perchlorates, in the form of chlorinated hydrocarbons. Other U.S. Mars robots — the Sojourner, Spirit and Opportunity — detected elemental chlorine. Moreover, orbital measurements taken by the Mars Odyssey spacecraft show that chlorine is globally distributed. [Phoenix principal investigator Peter Smith] said microbes on Earth use perchlorate for an energy source. They actually live off highly oxidized chlorine, and in reducing the chlorine down to chloride, they use the energy in that transaction to power themselves. In fact, when there's too much perchlorate in drinking water, microbes are used to clean it up, he said. Furthermore, seasonal flow features seen on Mars may be caused by high concentrations of the brines of perchlorate, which has a strong attraction to water and can drastically lower its freezing point, Smith told SPACE.com. The high levels of perchlorate found on Mars would be toxic to humans, Smith said."
Even if you want to introduce microbes, you'll need to find some that are useful under Martian conditions.
They are tough little bastards, so finding microbes that aren't killed will probably be easy enough; but finding ones that are metabolically active(rather than just capable of dormant endurance) could be trickier. Bacteria are pretty good at shriveling up and shrugging off downright alarming conditions(unprotected exposure to the vacuum of space, ionizing radiation, freezing, etc.); but they can't exactly shiver to keep themselves warm.
On the plus side, if you are planning on humans, you'll have to have a climate-controlled habitube setup anyway, so you could presumably use off-the-shelf perchlorate cleaner bacteria in 'scrubber' units that treat contaminated materials before they are introduced into the human support environment.
When was the last time an astronaut would survive exposure to anything outside Earth's atmosphere. Keep those helmets on kids, regulations and all that.
I imagine that the problem is astronauts in suits tracking dust back into the airlock and then, once unsuited, breathing in the perchlorate goodness, possibly with a side of delicious silicosis...
I remember reading about a scheme where the 'suit' would remain permanently outside the habitat, with a docking hatch in the rear, specifically to avoid this sort of contamination.
AIUI, it's not quite that simple.
On Earth, the extremophiles are believed to arisen in more benign environments, and evolved to colonize the extreme environments. It's not clear that Mars ever had the necessary benign environment for long enough for life to arise in the first place, let alone for it to evolve and begin to colonize the extreme margins. (Which, at the time, would have been far less extreme than currently.)
Ammonium Perchlorate is a very powerful oxidizer - and has been extensively used to make solid rocket propellant
Since Mars has so much perchlorates around why don't we turn Mars into planet-wide base for building solid rocket fuel ??
Muchas Gracias, Señor Edward Snowden !