LOS ANGELES: Written in the rust-red dust, sand, and rock of Mars is the history of water - a compound vital to organic life. A key tool for unlocking that history has started to trace ever-tighter orbits around the red planet. NASA’s 2001 Mars Odyssey orbiter, a solar-powered digital geologist launched last April, is preparing to take up a 2-1/2-year search for clues to the story of water - and, perhaps, of life - on Mars.
In the process, the craft, which arrived at Mars on Tuesday, is breathing new life into US efforts to explore a planet that has captivated the human imagination for millenniums. Mars Odyssey’s successful 285-million-mile journey stands in stark contrast to a pair of high-profile Mars missions in 1999 that reached the planet only to be destroyed.
The chemical makeup of rocks and minerals is expected to yield clues about the planet’s past climate and how that influenced on Mars’ water resources.
Researchers divide roughly into two camps on these topics. One holds that early in its history, the planet was warmer, wetter, and had an atmosphere thick enough to support the presence of vast amounts of surface water. The other camp posits that the planet has always been cold, and that any water would have been locked up as subsurface ice. Periodically, however, that ice could melt and gush to the surface.
The Mars Global Surveyor, has beamed back images of what appear to be relatively new gullies, washes, and debris flows. Some planetary geologists say these images are strikingly similar to aerial shots taken of US Southwestern desert slopes after flash floods and could have been formed after the sudden warming of water ice. Others hold that the formations could have been carved by the rapid release of fluidlike mixtures of soil and carbon-dioxide gas, which also can exist as subsurface ice. Based on the wide range of temperatures found to support elementary life forms on Earth, many astrobiologists suspect that either of the conditions on Mars could have allowed primitive life forms to emerge. For future missions
One factor that controllers will be watching is the Mars’ weather. The planet currently is in the grip of a global dust storm that began in late June. The sun is heating the upper layers of dust, boosting the upper atmosphere’s temperature by some 80 degrees F. As the atmosphere heats, it expands farther out into space and so could present more drag to the orbiter than originally envisioned.—Dawn/LATS Service (c) Christian Science Monitor.