Mars Rovers Sharpen Questions About Livable Conditions

Feb 15, 2008
Mars Rovers Sharpen Questions About Livable Conditions
This view from NASA's Mars Exploration Rover Opportunity shows bedrock within a stratigraphic layer informally named "Lyell," which is the lowermost of three layers the rover has examined at a bright band around the inside of Victoria Crater. Image credit: NASA/JPL-Caltech/Cornell University

Like salt used as a preservative, high concentrations of dissolved minerals in the wet, early-Mars environment known from discoveries by NASA's Opportunity rover may have thwarted any microbes from developing or surviving.

"Not all water is fit to drink," said Andrew Knoll, a member of the rover science team who is a biologist at Harvard University, Cambridge, Mass.

Opportunity and its twin, Spirit, began their fifth year on Mars last month, far surpassing their prime missions of three months. Today, at a meeting of the American Association for the Advancement of Science in Boston, scientists and engineers discussed new observations by the rovers, recent analysis of some earlier discoveries, and perspectives on which lessons from these rovers' successes apply to upcoming missions to Mars.

"The engineering efforts that have enabled the rovers' longevity have tremendously magnified the science return," said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' science payload. "All of Spirit's most important findings, such as evidence for hot springs or steam vents, came after the prime mission."

Opportunity spent recent months examining a bright band of rocks around the inner wall of a crater. Scientists previously hypothesized this material might preserve a record of the ground surface from just before the impact that excavated the crater. Inspection suggests that, instead, it was at the top of an underground water table, Squyres reported.

Experiments with simulated Martian conditions and computer modeling are helping researchers refine earlier assessments of whether the long-ago conditions in the Meridiani area studied by Opportunity would have been hospitable to microbes. Chances look slimmer. "At first, we focused on acidity, because the environment would have been very acidic," Knoll said. "Now, we also appreciate the high salinity of the water when it left behind the minerals Opportunity found. This tightens the noose on the possibility of life."

Conditions may have been more hospitable earlier, with water less briny, but later conditions at Meridiani and elsewhere on the surface of Mars appear to have been less hospitable, Knoll said. "Life at the Martian surface would have been very challenging for the last 4 billion years. The best hopes for a story of life on Mars are at environments we haven't studied yet -- older ones, subsurface ones," he said.

NASA's current rovers and orbiters at Mars pursue the agency's "follow the water" theme for Mars exploration. They decipher the roles and fate of water on a planet whose most striking difference from Earth is a scarcity of water. "Our next missions, Phoenix and Mars Science Laboratory, mark a transition from water to habitability -- assessing whether sites where there's been water have had conditions suited to life," said Charles Elachi, director of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Where conditions were habitable, later missions may look for evidence of life."

Elachi cited the achievements of Spirit and Opportunity. "They have worked 16 times longer than planned, driven 20 times farther than planned, and, most important, found diverse geological records of the effects of water in ancient Martian environments," he said. "We must not let these successes lull us into thinking this type of exploration is easy. Fifty years into the Space Age, we are still in the golden age of robotic exploration of our solar system, when each mission is unprecedented in some way as we push the limits of what is possible. Each mission presents new challenges."

The Phoenix lander, on course to reach Mars on May 25, will assess habitability of a shallow subsurface environment of icy soil farther north than any earlier mission has landed. It revives technology from missions launched before Spirit and Opportunity. The following mission, the Mars Science Laboratory rover, will incorporate many lessons from the current rovers, said that project's manager, Richard Cook of JPL. "The next rover will be much bigger to carry the instruments necessary for meeting its goals, but it would be laughable to consider doing Mars Science Laboratory without the experience gained from doing the Mars Exploration Rovers," he said.

The Mars Science Laboratory rover will weigh about four times as much as Spirit or Opportunity. "There's no way we could use an airbag landing," said JPL's Rob Manning, chief engineer for the future rover. Instead, a rocket-powered hovering stage will lower it to the surface on a tether. Lessons from Spirit and Opportunity will come into play when it starts driving, though. "With the current rovers, we've learned we can trust the autonomous navigation technology to a level we never expected, so now we can include that as a capability in our mission design for Mars Science Laboratory," Manning said.

Source: NASA

Explore further: NASA's space station Robonaut finally getting legs

add to favorites email to friend print save as pdf

Related Stories

Proposed Mars 'Icebreaker' mission detailed

8 hours ago

Scientists supported by the Astrobiology Technology for Exploring Planets (ASTEP) and Astrobiology Instrument Development Programs (ASTID) have outlined the proposed 'Icebreaker' mission to Mars in a recent ...

Recommended for you

NASA's space station Robonaut finally getting legs

3 hours ago

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Sun emits a mid-level solar flare

Apr 18, 2014

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

Impact glass stores biodata for millions of years

Apr 18, 2014

( —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

The importance of plumes

Apr 18, 2014

The Hubble Space Telescope is famous for finding black holes. It can pick out thousands of galaxies in a patch of sky the size of a thumbprint. The most powerful space telescope ever built, the Hubble provided ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

2 / 5 (1) Feb 16, 2008
Truly amazing science. What will happen there in the future is being bought and paid for by the robots we send now. Very interesting discoveries but not finding any microbes so far by reason of the acidity does not take into the fact that we in relatively recent times found new microbes that do indeed live in extremely harsh enviroments of heat and acidic surroundings. So why would we preclude that because of the high mineral deposits found on the surface of Mars, there would be none??? Perhaps it might look dismal but I would not say no to microbes being there. I guess we will find out someday when someone there gets a cut finger. Then what????
1 / 5 (2) Feb 16, 2008
For all those scientists that believe life is the result of random events and therefore must occur everywhere, it is interesting to see them back peddling and explaining away their previous certainty. According to their logic, life should have evolved on Mars. If the conditions were different then life should have evolved differently to suit those conditions. Their inconsistency is amusing.
4 / 5 (1) Feb 16, 2008
Andrew Knoll seems unaware of extremophiles.
All to often the specialists can't see outside "their" box.

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Cosmologists weigh cosmic filaments and voids

( —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.