Briny Water May Pool In Mars' Equatorial Soil

astroengine writes Mars may be a frigid desert, but perchlorate salts in the planet's soil are lowering the freezing temperature of water, setting up conditions for liquid brines to form at equatorial regions, new research from NASA's Curiosity rover shows. The discovery of subsurface water, even a trickle, around the planets warmer equatorial belt defies current climate models, though spacecraft orbiting Mars have found geologic evidence for transient liquid water, a phenomenon termed "recurring slope lineae." The findings, published in this week's Nature Geoscience, are based on nearly two years worth of atmospheric humidity and temperature measurements collected by the roving science laboratory Curiosity, which is exploring an ancient impact basin called Gale Crater near the planet's equator. The brines, computer models show, form nightly in the upper 2 inches of the planet's soil as perchlorates absorb atmospheric water vapor. As temperatures rise in the morning, the liquid evaporates. The levels of liquid, however, are too low to support terrestrial-type organisms, the researchers conclude. "It is not just a problem of water, but also temperature. The water activity and temperatures are so low in Mars that they are beyond the limits of cell reproduction and metabolism," Javier Martin-Torres, with Lulea University of Technology, in Kiruna, Sweden, wrote in an email to Discovery News.

Comments

Martian water is hypersaline

[Geoffrey.landis]

Yes, I've mentioned this before-- if there are bacteria on Mars, they will be extreme halophiles.
http://online.liebertpub.com/d...
http://ntrs.nasa.gov/search.js...

Yeay!

[Rei]

What great news for the prospect of life on Mars! Quantities of a chemical that destroys organics on contact are so great that they suck water out of the soil and air!

Nasa's massive obsession with this self-sterilizing rock come at the cost of investigating much more interesting targets elsewhere in the solar system. The money going to Mars 2020 in particular could do so much elsewhere (we really could use a followup to Titan, there's so many mysteries there we're not even close to solving, while new missions to Mars are more trying to find new mysteries to solve and answering the same vague "questions" over and over again) At least Europe is going to get something now - not my personal favorite (if there is anything interesting there, which we don't actually know, it's buried way too deep for us to get at it for a long, long time). But at least it's not NASA's "All Mars Channel".

Re:Yeay!

[Sowelu]

Mars takes ~260 days to reach, with a payload that could theoretically bring humans...maybe 130 if we do some pretty crazy stuff. Europa takes three years minimum for a much smaller payload. Actually getting humans to Mars is already a big technical challenge, let alone living once we get there...it's going to take a heck of a lot more practical experience before we can get them to Europa.

Say what you want about the pointlessness of living off-world, but Mars is great practice. It's closer, it has more solar power available, and we can send bigger things with our current technology. Same with the Moon...great practice, but even less practical reasons to be there than Mars.

Re:Yeay!

[sribe]

At least Europe is going to get something now - not my personal favorite (if there is anything interesting there, which we don't actually know, it's buried way too deep for us to get at it for a long, long time).

If you're really that curious about what's in Europe, why don't you just visit the next time you take a vacation?

Re:Yeay!

[HBI]

At the cost of doing nothing else.

Re:Yeay!

[Rei]

If your goal is living offworld, the most earthlike place in the solar system outside of Earth is the cloudtops of venus. A person could walk outside in shirtsleeves with just an oxygen-providing and eye-shielding face mask. Ordinary earth air is a lifting gas. Gravity is 0,9g. Aerocapture is simple. Water can be condensed straight from the cloudtops and oxygen hydrolized with the abundant solar power. There is zero dust to gum up the works (and the SO2 aspect is overplayed, even in the clouds it's not that concentrated).

If your goal is science, Mars isn't the place either, it's been way more studied than everywhere else but Earth and possibly the moon. People differ about what's the most scientifically interesting place but I'd argue that Titan has the most interesting unanswered questions.

If your goal is a colony that stands a chance of paying for itself (good luck with that), your best bet is an asteroid or cometary body (potentially with ice / CHONP, otherwise they can be shipped in with little delta-V from other asteroids / comets) that has abundant valuable metals in concentrated, non-oxidized forms for mining with little delta-V reqs for earth return or space use.

If your goal is a self-sustaining colony (a "backup earth" or whatnot), step out of the sci-fi novels. We're centuries away from that at best.

Re:Yeay!

[Rei]

Venus is actually the easiest place outside Earth and the Moon to have astronauts land... for broad definitions of "land" ;) See this comment.

Of course, anywhere you send humans you have to have an excuse of "them doing science", even though we all know that robots do it far cheaper. On Venus, you would have a floating lab analyzing the results of balloon probes repeatedly descending to the surface, collecting samples, and bringing them back up to the "livable" heights for analysis. For obvious reasons, humans would not be going down there.

Who knows - maybe they'd find something interesting there? Maybe Venus's hellish surface concentrates some sort of rare minerals that might justify large scale balloon collection and return. Some day. ;)

Re:Yeay!

[Rei]

Indeed, I prefer a relay too; I was just pointing out that it's not a fundamental requirement and there are mission proposals that don't use one.

Actually my "ideal" mission (a Titan sample return mission) has the relay probe be the propulsion stage (ion powered), and operating in a low orbit. While a tilt-rotor explorer would be exploring, the orbiter would be pumping its propellant tanks full of Titan's outer atmosphere (most ion engines are very propellant flexible, and the 1500m/s Titan atmosphere drag velocity is way less than the ion output velocity) and thus refilling its tanks for a return mission. So once the explorer returns on its ascent stage and re-docks, the propulsion stage now has full power and has full tanks for the return mission with the surface samples. Then back at Earth, not only are the surface samples returned, but also the residual Titan atmosphere in the propellant tanks. And both the propellant stage and explorer's (expensive) RTGs are recovered at the same time .

My ideal explorer is not a lander, but a tilt-rotor pontoon aircraft (I really don't see the point of fixed wing... tilt rotor adds in another driven component and joint, but it removes a corresponding required control surface, so it's a wash in terms of complexity, and it lets you land VTOL, then rest on the surface and recharge your flight batteries while doing surface science - aka, you can use a much smaller, cheaper RTG. Win-win-win. And while most propelled designs I've seen use ridiculously tiny quadcopter-ish motors to barely hold a heavy probe aloft (say a 0,5kg motor for a 120kg probe), my mission would have a several kilogram motor so that it'd have enough power to haul its ascent stage up to max flight altitude and velocity and reduce its delta-V reqs down to about 2k m/s. If the ascent stage has the same payload fraction as a Pegasus solid stage then that means that it'd only need to be about 150% the weight of whatever portion of the explorer you wish to return to orbit - totally doable. And the explorer doesn't need orbital maneuvering capability because you've got an ion-propelled propulsion stage out there that can come to you.

As an added bonus? You can do a stardust-style flyby of Enceladus for the added weight of a little aerogel, same with various rings, and a dip through the most extreme outer layers of Saturn with the scoop / pump feeding into a small sampling tank. Then it's not just a Titan sample return, but a Titan / Enceladus / Saturn sample return. And you save weight and cost on science experiments. You don't need to bring the science experiments to the Saturnian system, you just bring the Saturnian system back to Earth ;) No high power orbital radars or massive telescopic imagers like Cassini had, no surface chemistry experiments, no X-ray fluorescence setups... just a navcam on your propulsion stage, a multispectral pancam on your explorer so you can pick what to sample, and a good sampling arm with an abrasion tool (plus any flight hardware you can repurpose, such as the low power radar altimeter one would need).

Yeah, that'd probably be a Flagship mission. But my god, can you imagine how much data we'd get out of that?

(Concerning robotic arms... I was surprised how light they are when researching. MERs's very capable arms were barely over 4kg. Totally doable for even a mission where weight constraints are significant)