Phoenix science results, Beginning with December 2008 AGU meeting Options

[elakdawalla]

I figured it was time for a new thread, since we finally seem to be getting some science results out of Phoenix. The press release should be out shortly.

First numerical result I've heard was given by Peter Smith at today's press briefing at AGU: TEGA found that the soil is composed of 5% calcium carbonate, which is a significant result.

Hopefully more will hit the Web soon -- post here when the links go up!

--Emily

[alan]

Phoenix Site on Mars May Be in Dry Climate Cycle Phase

PASADENA, Calif. -- The Martian arctic soil that NASA's Phoenix Mars Lander dug into this year is very cold and very dry. However, when long-term climate cycles make the site warmer, the soil may get moist enough to modify the chemistry, producing effects that persist through the colder times.

Phoenix found clues increasing scientists' confidence in predictive models about water vapor moving through the soil between the atmosphere and subsurface water-ice. The models predict the vapor flow can wet the soil when the tilt of Mars' axis, the obliquity, is greater than it is now.
...
Cloddy texture of soil scooped up by Phoenix is one clue to effects of water. The mission's microscopic examination of the soil shows individual particles characteristic of windblown dust and sand, but clods of the soil hold together more cohesively than expected for unaltered dust and sand. Arvidson said, "It's not strongly cemented. It would break up in your hand, but the cloddiness tells us that something is taking the windblown material and mildly cementing it."

That cementing effect could result from water molecules adhering to the surfaces of soil particles. Or it could be from water mobilizing and redepositing salts that Phoenix identified in the soil, such as magnesium perchlorate and calcium carbonate.

The Thermal and Electrical Conductivity Probe on Phoenix detected electrical-property changes consistent with accumulation of water molecules on surfaces of soil grains during daily cycles of water vapor moving through the soil, reported Aaron Zent of NASA Ames Research Center, Moffett Field, Calif., lead scientist for that probe.

"There's exchange between the atmosphere and the subsurface ice," Zent said. "A film of water molecules accumulates on the surfaces of mineral particles. It's not enough right now to transform the chemistry, but the measurements are providing verification that these molecular films are occurring when you would expect them to, and this gives us more confidence in predicting the way they would behave in other parts of the obliquity cycles."

http://www.nasa.gov/mission_pages/phoenix/...x-20081215.html

[marsbug]

The Thermal and Electrical Conductivity Probe on Phoenix detected electrical-property changes consistent with accumulation of water molecules on surfaces of soil grains during daily cycles of water vapor moving through the soil, reported Aaron Zent of NASA Ames Research Center, Moffett Field, Calif., lead scientist for that probe.

Is this a complete turnaround from previous reports, or did I miss something?