Is There Life on Mars? NASA Goes Underground to Find Out

Next year NASA's Phoenix Lander will dig down into the surface of the arctic northern plains of the red planet, as recently announced by US scientists.

Phoenix will blast off in August, beginning a journey that will take several million miles and nine months to complete until the probe lands on Mars. Once there, Phoenix will deploy a set of advanced research tools never before used on the planet.

After the terrestrial discovery that exotic microbes exist in the rocks hundreds of meters beneath the floor of the Pacific Ocean, scientists have become more opened-minded about where and when life began.

Strange subterranean life on Earth is able to thrive without sunlight, exploiting dissolved gases and fluids, which percolate up from the depths of the Earth’s mantle. The primary producers are microbes that can convert inorganic substances directly into living material using chemical energy alone.

Jules Verne's science-fiction classic, Journey to the Center of the Earth aside, geologists have suggested the combined biomass of of microrganisms beneath Earth's surface may be several times that of all organisms, complex and simple, living on the surface above. Extremophiles have been found thriving in South African mines at depths of 3.5 kilometers; like their deep-sea vent counterparts, SLime communities (for subsurface lithoautotropic microbial ecosystem) can live independent of solar energy -surface and light. Deep rock microbe communities have been found trapped within their host rock for millions of years.

The significance of these discoveries for is that, though the surface is hostile to life, the warmer subsurface may be more congenial. And even if is dead today, life could have clung on underground for eons before planetary conditions worsened.

The new probe is a departure from past missions, which used robotic vehicles to explore the planet's surface hills and craters. Phoenix will actually dig down into Martian soil to assess if conditions are favorable to past or present life. Specifically, US scientists will use Phoenix to try and determine whether frozen water near the planet's surface might periodically melt enough to sustain a viable environment for microbes.

"Phoenix will complement our strategic exploration of by being our first attempt to actually touch and analyze Martian water—water in the form of buried ice," said Doug McCuistion, director of the Mars Exploration Program.

The solar-powered craft is equipped with a 2.3 meter (7.5 foot) robotic arm that will go vertically into the soil, aiming to strike the icy crust that is believed to lie within a few inches of the surface.

Peter Smith, Phoenix's principal investigator at the University of Arizona, Tucson, said the craft would be able to study the history of the ice and analyze how liquid water has modified the chemistry of the soil.

"In addition, our instruments can assess whether this polar environment is a habitable zone for primitive microbes," Smith said.

The Phoenix's robotic arm is capable of lifting samples to two instruments on its deck. One instrument will use a heater to check for water and carbon-based chemicals, while the other will analyze the soil chemistry.

The probe also hosts an onboard meteorology station, which will assess water and dust levels in the atmosphere, while tracking Martian weather during the three-month mission.

Posted by Rebecca Sato with Casey Kazan