Posted on 02/27/2004 10:14:02 AM PST by bogdanPolska12
LOS ANGELES (Reuters) - NASA (news - web sites) scientists said on Wednesday that they were within weeks of unlocking one of the key mysteries about Mars -- whether the arid planet once had water and was able to support life.
The rovers Spirit and Opportunity, working on opposite sides of the planet, have returned data from soil and rock samples that leave open the possibility that Mars once was warmer and wetter.
At the end of planned 90-day missions for the rovers, scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, should be able to determine what role, if any, water played in the planet's geological history, Ray Arvidson, deputy principal science investigator, said.
"Water is the elixir of life," Arvidson told reporters. "And if we come to the conclusion that water has been involved in the surface or subsurface at some time in the past, then I think the probability that ... life could have gotten started goes way up."
He said scientists would need "a couple dozen more sols," or martian days, to finish critical measurements, download data from the rovers and narrow several working hypotheses about the planet's geological history, not all of which include a role for water.
WIND, LAVA, WATER
Opportunity has spent 33 sols on Mars studying finely layered bedrock in the small crater where it landed at Meridiani Planum near the planet's equator.
Scientists were puzzling out whether the layers were formed by wind, volcanic lava floes or water, and if spherical "blueberries" discovered in the rocks were water-related.
The rover has sent back high-definition and microscopic images as well as data about the composition of the rocks and soil that suggest the presence of gray hematite, which on Earth can form in oxygenated water.
Opportunity's spectrometers have detected a large deposit of hematite in the surrounding plains and in a flat area of bedrock nicknamed Charlie Flats, which held a variety of soil and rock types, Jim Bell, JPL's panoramic camera scientist, said.
"We can't unequivocally say this is coarse-grained gray hematite, but it's a hypothesis we are putting forward," he said. "We really need some better compositional information."
The "blueberries," found throughout the bedrock, may have formed in a water-charged volcanic explosion, from iron-bearing minerals that corroded in water or from molten rock that sprayed into the air and solidified as spheres as it fell to the ground, Arvidson said.
"We're getting chemistry and mineralogy from a number of sites to put the whole story together," he said. "That story is right around the corner but we need to finish this work in progress."
Spirit, now in its 53rd sol, has cut a zig-zagging path from its lander through an increasingly dense field of rocks toward a 15-meter (49 ft) deep crater nicknamed Bonneville.
Inside the crater, scientists hope to pierce the planet's surface layer of volcanic basalt to reach more ancient rocks and soil that may have been formed by water.
Spirit rests in a hollow named Middle Ground, about 110 meters (361 ft) northeast of its landing site. The rover, equipped with a suite of scientific instruments, has been sampling soil and rocks along the way to the 150-meter (492 ft) wide crater.
Engineers plan to upgrade the rover's software in a couple of weeks to allow it to move more quickly through the rocky ground and to negotiate Bonneville Crater's steep rim.
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