Mars Exploration

Adv. Bio-2

Indeed, NASA experts say their entire game plan for the latest stage of Mars exploration is based on sending twin robotic rovers, Spirit and Opportunity, to two spots on the red planet where the evidence of water is most compelling.

Spirit landed on Saturday night in the heart of Gusev Crater, a massive basin larger than Connecticut that was carved out by the impact of an asteroid or comet early in Mars\' history and is thought to have once held a gigantic lake.

A long, deep valley apparently chiseled by ancient flows of water leads into Gusev, suggesting it was fed by an ancient river.

In three weeks NASA plans to land Opportunity on the so-called Meridiani Planum, a smooth plain near Mars\' equator where NASA\'s orbiting Mars Global Surveyor has detected an abundance of gray hematite, a mineral that on Earth usually forms in association with liquid water.

Some environmental conditions that can produce hematite, such as a lake or hot springs, could be hospitable to life. Others, such as hot lava, would not.

Determining whether Mars ever supported living things would provide scientists with valuable insights into the evolution of life on Earth and the question of how rare or common life may be throughout the universe, Elachi said.

Although scientists believe the odds are slim that advanced forms of life like those on Earth could have evolved on Mars\' comparatively hostile environment, there is reason to believe that simple, microscopic organisms may have once existed at a time when Mars was warmer and wetter.

It is even possible that primitive life forms may now be present beneath Mars\' thick polar ice caps or in subterranean springs warmed by heat vents around smoldering volcanoes. There could also be martian equivalents of lithotrophs, single-celled microbes that dwell in bedrock.

The two rovers are designed to roam the surface of Mars for about three months seeking to unlock clues to the mystery of water on Mars by examining its rocks and soil.

The Spirit will survey its general environs with a pair of high-resolution, panoramic cameras mounted on a mast and with a spectrometer that measures the infrared radiation emitted by minerals. Together, these instruments will help scientists pick which areas to explore first with the rover.

The rover carries several more gadgets on its robotic arm to conduct remote-controlled geologic studies, including a microscopic camera to give scientists extreme close-up views of minerals, a tool to grind away the outer layer of rocks, and an instrument to analyze the composition of rocks and soil.

Besides Earth, which is Mars\' closest planetary neighbor, the only place in the solar system where water is believed to exist is Europa, a moon of Jupiter, where a liquid ocean may lie beneath an icy crust.