Curiosity (Mars Science Lab)

A new theory is pouring some cold — actually, some really hot — water on the idea that Mars could have been habitable in the past.

Planetary scientists searching the Red Planet for places that could have contained the building blocks for life look for clues in clays, which can offer some indication that water must have flowed on or just under Mars' surface. But a new study suggests that, at least in some cases, those clays might be a red herring.

A paper published online Sunday by the journal Nature Geoscience argues that such clays might have been formed in hot Martian magma rich in water. If so, that water would have been far too hot to support microbial life.

The argument stands in contrast to two more common theories, said study coauthor Bethany Ehlmann, a planetary geologist at Caltech. One of them is that liquid water flowing across the Martian surface would have interacted with surrounding minerals, forming the clays. In another scenario, underground water warmed by the planet's internal heat could have provided a comfortable living before it got bound up in the mineral structure of clays.

The Mars rover Curiosity might shed some light on the debate by giving scientists a close-up look at some clays in the lower layers of Mount Sharp in the middle of Gale Crater. It is expected to arrive in about a year.

NASA’s Curiosity rover has found evidence of strong streams that once gushed across the Martian surface, mission scientists said Thursday.

Curiosity landed in Gale Crater on Aug. 5. But now, less than a couple of months into the Mars Science Laboratory’s two-year mission, the Red Planet rover used its Mast Camera to examine rocks on its way to Glenelg Intrigue. Glenelg has caught scientists’ eyes because the odd spot serves as a junction between three different types of terrain.

The two outcrops in between, named Link and Hottah, have provided some exciting results in the meantime. The mission’s head scientist, Caltech geologist John Grotzinger, described the outcrop at Hottah as a raised cement section in a ”jackhammered urban sidewalk,” possibly caused by an impact on the surface.

The telltale rocks are made of sandy rock riddled with large pebbles. The shape of those pebbles tells the scientists that the rocks must have traveled a long way, bumping into each other and smoothing out the rough edges. The relatively large size of many of those stones – some the size of a golf ball – tells them that water, not wind, must have carried them.

Such rocks could have traveled 20 to 25 miles and started out rough and blocky, big as a football, before being ground down to their current size, the scientists said.

“This is a rock that was formed in the presence of water, and we can characterize that water as being a vigorous flow,” Grotzinger said.

This image taken by the rover Curiosity shows a rock outcrop on Mars. The outcrop, named Hottah, is believed to hold evidence of an ancient, flowing stream.

Nasa's Curiosity rover has ingested its first Martian soil sample.

The robot has taken a pinch of dust into the CheMin instrument, one of its two big onboard analytical tools.

It is a key moment for the $2.6bn mission - Curiosity's internal apparatus will play a central role in its investigation of the Red Planet.

"The most important thing about our mobile laboratory is that it eats dirt - that's what we live on," chief scientist John Grotzinger told the BBC.

CheMin provides definitive mineralogy – it uses X-ray diffraction to identify and quantify the minerals present in the rocky material that has been swallowed.

Engineers received confirmation on Thursday that the sample was accepted by the instrument, and details of the analysis may be available as early as next week.

(A) Curiosity will trundle around its landing site looking for interesting rock features to study. Its top speed is about 4cm/s
(B) This mission has 17 cameras. They will identify particular targets, and a laser will zap those rocks to probe their chemistry
(C) If the signal is significant, Curiosity will swing over instruments on its arm for close-up investigation. These include a microscope
(D) Samples drilled from rock, or scooped from the soil, can be delivered to two hi-tech analysis labs inside the rover body
(E) The results are sent to Earth through antennas on the rover deck. Return commands tell the rover where it should drive next

The first red sands of Martian soil scooped up by the rover Curiosity are much like the weathered volcanic soils of Hawaii, the mission's scientists reported Tuesday.

The sands - more a kind of orange-tan than red - are tiny crystals of minerals most people know from school, like feldspar, olivine and pyroxine. They are widespread on the surface of Curiosity's landing area called Gale crater, possibly blown there by Martian winds or the remnants of ancient erupting volcanoes, the scientists said.

A remarkable instrument aboard Curiosity, developed by David Blake, a cosmochemist at NASA's Ames Research Center in Mountain View, identified the minerals with its X-ray beams probing tiny sand grains no thicker than a human hair.

The instrument, called CheMin, for chemistry and mineralogy, is a marvel of miniaturization. No larger than a shoe box, it fits inside the rover and does the same analytic work as X-ray diffraction instruments the size of refrigerators, Blake said.

In the first maneuvers for the instrument, after barely three months on Mars, Curiosity scooped up sand samples the size of aspirin tablets and delivered them to CheMin, which shook them at 2000 times a second to get rid of larger grains, and then bombarded the remaining crystals to reveal their precise atomic structure in a process called X-ray diffraction.

The Mars Hand Lens Imager (MAHLI) on the arm of NASA's Mars rover Curiosity took this image of a rock called "Et-Then" during the mission's 82nd sol, or Martian day (Oct. 29, 2012). Et-Then is located near the rover's front left wheel, where the rover has been stationed while scooping soil at the site called "Rocknest."

The Curiosity Mars rover has discovered something interesting in a scoop of ruddy sand, but NASA scientists say they’re not quite sure what it means.

Sand that was shaked-and-baked inside the car-size rover’s chemistry kit bubbled off traces of organic compounds, mission scientists said at a press briefing Monday at the annual meeting of the American Geophysical Union.

Such compounds, made of carbon and chlorine, are of the type that, in some cases, indicate microbes in the soil.

But such compounds also could be contamination from the rover itself — or they may have rained onto the surface inside meteorites, said Paul Mahaffy, a mission scientist from NASA’s Goddard Space Flight Center in Greenbelt.

“It’s unclear if the carbon is Martian or terrestrial,” Mahaffy said.

Further tests will help clarify the source of the chemicals, but mission scientists cautioned that the rover is not equipped to find life itself, only the conditions that may be ripe for life.

If they rule out contamination, the science team will “get into the complex question of whether this is some type of biological material,” said project scientist John Grotzinger. “That’s well down the line for us.”

While many obsessed over speculation that NASA’s newest Mars rover, Curiosity, had dug up signs of life — it had not — it is the agency’s older, smaller jalopy, Opportunity, that has been exploring a more intriguing plot of Martian real estate.

“This is our first glimpse ever at conditions on ancient Mars that clearly show us a chemistry that would have been suitable for life,” Steven W. Squyres, the principal investigator for Opportunity, said at a news conference last week at a meeting of the American Geophysical Union here.

Opportunity could be sitting on rocks chock-full of organic molecules — but the rover and the scientists back on Earth would never know. Unlike Curiosity, Opportunity is not carrying instruments that can detect those kinds of molecules.

But the scientists are not complaining. Everything from Opportunity over the past eight years has been a bonus for a mission that was to have ended long ago.

For the first time in history, humans have drilled a hole into rock on Mars and are collecting the powdered results for analysis, NASA announced Saturday.

After weeks of intensive planning, the Mars rover Curiosity undertook its first full drill on Friday, with NASA receiving images on Saturday showing that the procedure was a success.

Curiosity drilled a hole that is a modest 2.5 inches (6.35 centimeters) deep and .6 inches (1.52 centimeters) wide but that holds the promise of potentially great discoveries.

"The most advanced planetary robot ever designed now is a fully operating analytical laboratory on Mars," John Grunsfeld, NASA associate administrator for the agency's Science Mission Directorate, said in a statement on Saturday.

"This is the biggest milestone accomplishment for the Curiosity team since the sky-crane landing last August."

Several billion years ago, Mars may well have been a pleasant place for tiny microbes to live, with plenty of water as well as minerals that could have served as food, NASA scientists said Tuesday at a news conference on the latest findings from their Mars rover. But they have yet to find signs that actual microbes did live in that oasis.

“We have found a habitable environment that is so benign and supportive of life that probably if this water was around and you had been on the planet, you would have been able to drink it,” said John P. Grotzinger, the California Institute of Technology geology professor who is the principal investigator for the NASA mission.

In drilling into its first rock, a fine-grained mudstone, the scientists said, the rover Curiosity — a self-contained science laboratory about the size of a Mini Cooper — sent back to Earth convincing evidence that Mars was once awash in water.

Plus, the Curiosity scientists identified elements in the rocks — sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — that are some of the key ingredients of life, as well as minerals, like sulfates and sulfides, that primitive microbes could eat for food. Dr. Grotzinger said these minerals are “effectively like batteries” and can provide an energy source for life.

This included the presence of clays, one of the main things that scientists were hoping that Curiosity would find on its two-year, $2.5 billion mission. Clays form in waters that have a neutral pH.