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Four years into its travels across Mars, NASA’s Curiosity rover faces an unexpected challenge: wending its way safely among dozens of dark streaks that could indicate water seeping from the red planet’s hillsides.
Although scientists might love to investigate the streaks at close range, strict international rules prohibit Curiosity from touching any part of Mars that could host liquid water, to prevent contamination. But as the rover begins climbing the mountain Aeolis Mons next month, it will probably pass within a few kilometres of a dark streak that grew and shifted between February and July 2012 in ways suggestive of flowing water.
NASA officials are trying to determine whether Earth microbes aboard Curiosity could contaminate the Martian seeps from a distance. If the risk is too high, NASA could shift the rover’s course — but that would present a daunting geographical challenge. There is only one obvious path to the ancient geological formations that Curiosity scientists have been yearning to sample for years (see ‘All wet?’).
[...] The streaks — dubbed recurring slope lineae (RSLs) because they appear, fade away and reappear seasonally on steep slopes — were first reported 1 on Mars five years ago in a handful of places. The total count is now up to 452 possible RSLs. More than half of those are in the enormous equatorial canyon of Valles Marineris, but they also appear at other latitudes and longitudes. “We’re just finding them all over the place,” says David Stillman, a planetary scientist at the Southwest Research Institute in Boulder, Colorado, who leads the cataloguing.
[...] Curiosity was only partly sterilized before going to Mars, and experts at JPL and NASA headquarters in Washington DC are calculating how long the remaining microbes could survive in Mars's harsh atmosphere — as well as what weather conditions could transport them several kilometres away and possibly contaminate a water seep. "That hasn't been well quantified for any mission," says Vasavada.
http://www.nature.com/news/mars-contamination-fear-could-divert-curiosity-rover-1.20544
(Score: 3, Interesting) by shrewdsheep on Thursday September 08 2016, @08:11AM
OTOH, earth germs would be distinguished from Mars germs easily by genetic means (should Mars also be driven by DNA). Also it is unlikely that germs would spread quickly on Mars so that other sites should stay pristine for centuries to come. That being said, it is also a matter of scientific integrity to stick to the original plan. It is of course useful to do the calculations that are underway for other reasons too. It would inform the planning and analysis of later missions. However, I would not see it as a catastrophe if contamination would factually happen.
(Score: 2) by Phoenix666 on Thursday September 08 2016, @10:50AM
That's a really good point. Unless there's some sort of subterranean, global aquifer on Mars through which contamination might spread throughout the planet. That seems unlikely. It is much more of a risk on Europa or Enceladus, so I do hope the probes we send to those places are thoroughly sterilized before they're sent.
Or maybe that's what the aliens thought when they sent their probes to early Earth and thought, 'meh, what harm could it do that we didn't sterilize the thing fully before we sent it there?...'
Washington DC delenda est.
(Score: 0) by Anonymous Coward on Thursday September 08 2016, @02:03PM
Lets be honest here as well, exactly how likely is it for "earth germs" to actually survive the trip and 18 more months on the planet surface. These are things that have evolved to have air and water to survive, of which they have had 0 for the past few years.
(Score: 1, Informative) by Anonymous Coward on Thursday September 08 2016, @02:47PM
You would be surprised what a simple enough organism can survive.
(Score: 0) by Anonymous Coward on Thursday September 08 2016, @07:25PM
Oh, I don't know, fair to middlin' [extremetech.com] I'd say.
(Score: 3, Insightful) by jimtheowl on Thursday September 08 2016, @10:40PM
I am not a certified exobiologist, but allow me to make speculations of my own:
What if the "germs" are very similar to the ones on Earth? Could we then figure out for sure if they were introduced from Earth but then mutated? Would we then be able to find out if they were introduced by us recently, or via meteorites (with a very slow rate of mutation)?
What if life evolved independently, but has a very high probability of organizing in the same patterns? Perhaps it is a result of life originating from Mars, or even the reverse; that Mars was contaminated by Earth. Why would you assume that it would spread slowly given factors such as the wind?
What if life evolved independently, but only one of the two planets was subject to contamination? It could be that 10% of the DNA material on Earth is from Mars, but not the opposite. Without a proper data set from Mars it may be impossible to intersect the data and extract what the original Earth DNA is.
And what if they are significantly different? Could it then for sure not be attributed to mutations only?
It might be a bit naive to presume what we will be able to conclude if we only have contaminated data.
(Score: 2) by el_oscuro on Friday September 09 2016, @12:13AM
We actually have no way of verifying it either way, as contamination has been occurring for many millions of years before we got there. We found that meteorite from Mars in Antarctica. It would be perfectly reasonable to expect that Mars has some Earth meteorites.
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(Score: 2) by jimtheowl on Monday September 12 2016, @12:01AM