Credit: NASA/JPL-Caltech/University Arizona/Texas A&M University

Laboratory tests aboard NASA's Phoenix Mars Lander, currently on a mission in the northern polar region of the Red Planet, have identified water in a Martian soil sample. The lander's robotic arm delivered the sample on 30 July to an onboard instrument that identifies vapors produced by the heating of samples.

"We have water," said William Boynton, lead scientist for the Thermal and Evolved-Gas Analyzer, TEGA. "We've seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks observed by Phoenix last month, but this is the first time Martian water has been touched and tasted."

With intriguing results so far and the spacecraft operating well, NASA will extend the Phoenix mission through 30 September 2008. The prime mission was scheduled to be three months long; the mission extension adds five weeks.

"Phoenix is healthy and the projections for solar power look good, so we want to take full advantage of having this resource in one of the most interesting locations on Mars," said Michael Meyer, chief scientist for the Mars Exploration Program at NASA Headquarters in Washington.

The soil sample was taken from a trench approximately 5 cm deep. When the robotic arm of the lander first probed that depth, it hit a hard layer of frozen soil. Two attempts to deliver samples of icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop. Most of the material in 30 July’s sample had been exposed to the air for two days, allowing some of the water in the sample vaporize away and making the soil easier to handle.

"Mars is giving us some surprises," said Phoenix principal investigator Peter Smith. "We're excited because surprises are where discoveries come from. One surprise is how the soil is behaving. The ice-rich layers stick to the scoop when poised in the Sun above the deck, different from what we expected from all the Mars simulation testing we've done. That has presented challenges for delivering samples, but we're finding ways to work with it and we're gathering lots of information to help us understand this soil."

Since landing on 25 May 2008, Phoenix has been studying soil with a chemistry lab, TEGA, a microscope, a conductivity probe and cameras. Besides confirming the 2002 finding from orbit of water ice near the surface and deciphering the newly observed stickiness, the science team is trying to determine whether the water ice ever thaws enough to be available for biology and if carbon-containing chemicals and other raw materials for life are present.

The mission is not only studying the soil, it is observing the Martian sky as well. A Canadian instrument is using a laser beam to study dust and clouds overhead. "It's a 30-watt light bulb giving us a laser show on Mars," said Victoria Hipkin of the Canadian Space Agency.
A full-circle, color panorama of Phoenix's landing site also has been accomplished by the spacecraft.

"The details and patterns we see in the ground show an ice-dominated terrain as far as the eye can see," said Mark Lemmon, lead scientist for Phoenix's Surface Stereo Imager camera. "They help us plan measurements we're making within reach of the robotic arm and interpret those measurements on a wider scale."

Further Reading

NASA’s Phoenix Website
http://www.nasa.gov/mission_pages/phoenix/main/index.html

Aymen Mohamed Ibrahem
Senior Astronomy Specialist