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Exploring the layer of ice at Mars' north pole

An image taken by the robotic arm (RA) camera pointed under the Lander, showing the ice table exposed by the thrusters.
[Image courtesy of Science/AAAS]

NASA's Phoenix mission landed on the planet Mars in May 2008, and explored the surface of the Red Planet for more than five months. New data from the Phoenix Mars Lander confirms that there is a layer of ice water at the Martian north pole about five to 18 centimeters beneath the soil.

Peter Smith and colleagues used tools on board the Phoenix Lander, such as the 2.35-meter Robotic Arm and the Icy Soil Acquisition Device, to dig into the Martian soil for the first time and analyze the properties of the ice below. Their results are published in the latest issue of the journal Science.

Enhanced-color nighttime image of surface frost on Mars.
[Image courtesy of Science/AAAS]

The researchers say that experiments with the ice layer suggest that liquid water was once present there, and that it physically modified the soil in the past. Smith and his team then analyzed the interaction between water in the atmosphere and the ground, and found that the soil absorbs water vapor from the air at night. This finding also provides more evidence of ancient liquid water at the landing site.

More experiments with the Phoenix Lander revealed that the Martian soil was basic, not acidic, at the north pole. It is made up of various salts and aqueous minerals, and the researchers suggest that the formation of the minerals, long ago, probably required the presence of water too.

Taken together, these findings imply that the north pole of Mars could have met the criteria for habitability at some time in the past.


This research appears in the 03 July 2009 issue of Science.