The Black Vault - Mars Orbiters Chip Away at an Icy World

NASA's Mars Odyssey is chipping away at how and where ice forms on the red planet. New data is helping shape future strategies of exploring Mars, looking for life, and supporting future human explorers.

Frozen layers of carbon-dioxide frost or snow accumulate during northern Mars' winter, then dissipate in the spring. That process exposes a soil layer rich in water ice, the Martian counterpart to permafrost. Coupling Mars Odyssey data with laser altimeter information gleaned by the Mars Global Surveyor (MGS), the amount of dry ice during the northern winter and spring seasons is being revealed.

In some places, the water-ice content is more than 90 percent by volume, reports Odyssey's Igor Mitrofanov of the Russian Space Research Institute, Moscow, in the June 27 issue of the journal Science. He and his co-researchers assessed MGS laser altimeter data taken more than two years ago to explore the implications of the seasonal changes.

Another report, to be published in the Journal of Geophysical Research-Planets, combines measurements from the two Mars orbiting probes to provide indications of how densely the winter layer of carbon-dioxide frost or snow is packed at northern latitudes greater than 85 degrees. William Feldman of Los Alamos National Laboratory in New Mexico led that study.

Feldman and his associates also found that, once the dry ice disappears, the remaining surface near the pole is composed almost entirely of water ice.

Meanwhile Mars researchers James Head of Brown University and David Marchant of Boston University report that cold-based mountain glaciers exist on the red planet.

In the July issue of the Geological Society of America’s magazine, Geology, they provide evidence that large cold-based mountain glaciers existed on the flanks of the large Tharsis Montes equatorial volcanoes in the recent geological past.

Using newly acquired MGS data, backed by a trek to Antarctica, the investigators point to Arsia Mons, Tharsis Rise as the site of mountain glacier formation. Moreover, deposits there may still contain glacial ice below the surface and thus hold the record of ancient climatic conditions on Mars. Such deposits may provide water resources for future human explorers, the Mars experts suggest.

http://www.space.com/scienceastronomy/odyssey_update_030627.html