Posted: August 1, 2008
After weeks of struggling to deliver a sample of icy soil to Phoenix’s onboard laboratory, the lander’s ovens have finally received their bounty and provided the first direct evidence for water on Mars.
"We have water," says William Boynton, lead scientist for the Thermal and Evolved-Gas Analyser (TEGA), the instrument that sniffed out the water vapour as the sample was heated to progressively higher temperatures. "We've seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks [of ice] observed by Phoenix last month, but this is the first time Martian water has been touched and tasted."
A full-circle, colour panorama of Phoenix's surroundings also has been completed by the spacecraft, showing an ice-dominated terrain as far as the eye can see. The image will help mission scientists plan future measurements within reach of the robotic arm and then interpret the results with how they fit into the global picture. Image: NASA/JPL-Caltech/University Arizona/Texas A&M University.
The soil sample came from a section of the ‘Dodo-Goldilocks’ trench extending to about 5 centimetres deep, where a hard layer of frozen soil was discovered earlier in the mission. Two attempts to deliver samples of the icy soil were foiled when they became stuck inside the scoop, and no amount of shaking or vibrating helped release the stubborn soil. But in the latest attempt, the soil had been exposed to the Martian air for around two days, allowing some of the water locked up in the soil to vapourise away, making it less ‘sticky’ and easier to work with.
"Mars is giving us some surprises," says Phoenix principal investigator Peter Smith of the University of Arizona. "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."
With these tantalizing results and the lander given a clean bill of health, NASA also announced additional funding for the mission to continue through to the end of September, adding an extra five weeks to an originally planned 90 day mission.
"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," says Michael Meyer, chief scientist for the Mars Exploration.
During that time, the science team will try to determine whether the water ice ever thaws enough to be available for life as liquid water, and if carbon-containing chemicals and other raw materials required for life as we know it are present.
Jul 29 Sticky situation for Phoenix read more
Jul 22 Phoenix in 24-hour monitoring assignment read more
Jul 17 Phoenix rasps frozen layer... read more
Jul 11 First success with Phoenix soil probe... read more
Jul 10 Phoenix struggling with icy payload read more
Jul 03 Next Phoenix bake could be last read more
Jun 30 Phoenix soil could support life read more
Jun 23 Frozen water confirmed on Mars read more
Jun 19 Bright chunks must have been ice read more
Jun 17 First results from Phoenix bakery read more
Jun 12 An oven full of sand read more
Jun 10 Clumpy Martian soil challenges Phoenix read more
Jun 06 Closest view ever of Mars sand read more
Jun 03 Phoenix scoops up Martian soil read more
Jun 02 Phoenix sees possible ice read more
May 30 Phoenix flexes robotic arm read more
May 28 HiRISE captures Phoenix descent read more
May 26 Spectacular new colour view of Mars read more
May 23 Phoenix prepares for Mars landing read more