New findings from NASA’s Mars Reconnaissance Orbiter (MRO) 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).
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.”
3D-Printed Ice Houses Win NASA’s Mars Habitat Competition
NASA has deemed SEArch (Space Exploration Architecture) and Clouds AO (Clouds Architecture Office) winners of the 3D-Printed Habitat Challenge for Mars. Sponsored by NASA and America Makes, the teams were asked to use indigenous materials and 3D printing techniques to build a habitat for four astronauts on Mars. SEArch and Clouds AO’s first prize proposal, ICE HOUSE was awarded $25,000, ahead of 30 other shortlisted practices.
“Recognizing that water is the building block to life, the team used a ‘follow the water’ approach to conceptualize, site and construct their design,” said SEArch and Clouds AO. “[Our] proposal stood out as one of the few entries not to bury the habitat beneath regolith, instead mining the anticipated abundance of subsurface ice in the northern regions to create a thin vertical ice shell capable of protecting the interior habitat from radiation while celebrating life above ground.”
The architecture of ICE HOUSE celebrates the presence of a human habitat as a beacon of light on the Martian surface. The design emerged from an imperative to bring light to the interior and to create visual connections to the landscape beyond, allowing the mind as well as the body to thrive. While scientists have experimented with what could potentially be synthetic replacements for sunlight, artificial substitutes do not hold nearly the same circadian variance or ability to balance a crew’s mental and physical health as does experiencing the sun’s actual and unmediated daily cycles. The water ice counteracts the traditional danger of living above ground by serving as a radiation barrier, offsetting fears of solar exposure that have, until now, projected Martian architecture into a dark underworld—buried beneath a regolithic surface that is believed to contain perchlorates, gypsum and other substances hazardous to human life.
Read More about the winners