NASA’s Mars mystery revealed as … evidence of water found under surface!

Last week, NASA teased a major scientific finding from their exploration of Mars, to be released during a major press conference at NASA Headquarters in Washington. Well, the news has been published in Nature magazine, and holy *&^&*, did they not disappoint. As SF author Ray Bradbury once wrote in his brilliant The Martian Chronicles, “The Martians were there – in the canal – reflected in the water.”

Not aliens, as many people have been hoping, but water under the surface. The game was rather given away by the presence of Lujendra Ojha on the NASA guest list, who discovered potential signs of water on Mars while working still as an undergraduate student. That must have been one heck of a dissertation!

In a Nature Geoscience paper published today, Ojha and his colleagues working with the tools of the Mars Reconnaissance Orbiter have shown that liquid water still flowing on Mars’ surface is forming the tear stains known as recurring slope lineae – areas of tear-like salt streaking down Martian slopes. The lineae appear in the Martian summer, growing and then fading by winter.

Ojha said, “Whatever is flowing on Mars is hydrating the salt and we’re seeing that hydration in the spectral signature.”

The origin of the water is still an unknown, although active underwater aquifers would be the most obvious source. Ojha admitted, “That’s the big mystery right now.”

Beyond the purely scientific ramifications of this discovery, the practical implications for colonization have just been Judo flipped 360 degrees and slapped down in the – rather wet – Martian surface.

“If they are announcing that they have found easily accessible, freely flowing liquid water under the surface, which is one of the theories we have been hearing for years and years, that has massive implications both for the potential for life on that planet and sustainability of humans,” noted Doug McCuistion, the former head of Nasa’s Mars programme, speaking to U.S newspapers including the Boston Herald before the publication of the Nature Geoscience paper. “That would be highly enabling and might be the game-changing trigger for both finding life and hurrying up and getting people to Mars. If it is already there and you don’t have to bring it, that could save you many, many metric tons of resupply as well as initial carrying capacity and landing mass … if you take water out of the equation that is going to lighten the load significantly.”

Here’s today’s full official report from NASA:

New findings from NASA’s Mars Reconnaissance Orbiter provide the strongest evidence yet that liquid water flows intermittently on present-day Mars.

Using an imaging spectrometer on MRO, researchers detected signatures of hydrated minerals on slopes where mysterious streaks are seen on the Red Planet. These darkish streaks appear to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. They appear in several locations on Mars when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius), and disappear at colder times.

“Our quest on Mars has been to ‘follow the water,’ in our search for life in the universe, and now we have convincing science that validates what we’ve long suspected,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington. “This is a significant development, as it appears to confirm that water — albeit briny — is flowing today on the surface of Mars.”

These downhill flows, known as recurring slope lineae (RSL), often have been described as possibly related to liquid water. The new findings of hydrated salts on the slopes point to what that relationship may be to these dark features. The hydrated salts would lower the freezing point of a liquid brine, just as salt on roads here on Earth causes ice and snow to melt more rapidly. Scientists say it’s likely a shallow subsurface flow, with enough water wicking to the surface to explain the darkening.

“We found the hydrated salts only when the seasonal features were widest, which suggests that either the dark streaks themselves or a process that forms them is the source of the hydration. In either case, the detection of hydrated salts on these slopes means that water plays a vital role in the formation of these streaks,” said Lujendra Ojha of the Georgia Institute of Technology (Georgia Tech) in Atlanta, lead author of a report on these findings published Sept. 28 by Nature Geoscience.

Ojha first noticed these puzzling features as a University of Arizona undergraduate student in 2010, using images from the MRO’s High Resolution Imaging Science Experiment (HiRISE). HiRISE observations now have documented RSL at dozens of sites on Mars. The new study pairs HiRISE observations with mineral mapping by MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).

The spectrometer observations show signatures of hydrated salts at multiple RSL locations, but only when the dark features were relatively wide. When the researchers looked at the same locations and RSL weren’t as extensive, they detected no hydrated salt.

Ojha and his co-authors interpret the spectral signatures as caused by hydrated minerals called perchlorates. The hydrated salts most consistent with the chemical signatures are likely a mixture of magnesium perchlorate, magnesium chlorate and sodium perchlorate. Some perchlorates have been shown to keep liquids from freezing even when conditions are as cold as minus 94 degrees Fahrenheit (minus 70 Celsius). On Earth, naturally produced perchlorates are concentrated in deserts, and some types of perchlorates can be used as rocket propellant.

Perchlorates have previously been seen on Mars. NASA’s Phoenix lander and Curiosity rover both found them in the planet’s soil, and some scientists believe that the Viking missions in the 1970s measured signatures of these salts. However, this study of RSL detected perchlorates, now in hydrated form, in different areas than those explored by the landers. This also is the first time perchlorates have been identified from orbit.

MRO has been examining Mars since 2006 with its six science instruments.

“The ability of MRO to observe for multiple Mars years with a payload able to see the fine detail of these features has enabled findings such as these: first identifying the puzzling seasonal streaks and now making a big step towards explaining what they are,” said Rich Zurek, MRO project scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

For Ojha, the new findings are more proof that the mysterious lines he first saw darkening Martian slopes five years ago are, indeed, present-day water.

“When most people talk about water on Mars, they’re usually talking about ancient water or frozen water,” he said. “Now we know there’s more to the story. This is the first spectral detection that unambiguously supports our liquid water-formation hypotheses for RSL.”

The discovery is the latest of many breakthroughs by NASA’s Mars missions.

“It took multiple spacecraft over several years to solve this mystery, and now we know there is liquid water on the surface of this cold, desert planet,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at the agency’s headquarters in Washington. “It seems that the more we study Mars, the more we learn how life could be supported and where there are resources to support life in the future.”