October 18, 2005

Rovers Find Traces of Salt, New Mars Crater

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The Mars Rovers continue to make progress nearly 640 days after landing on Mars. Every day since the landing, scientists from around the world have conversed via teleconference to plan the following day’s schedule for activity.

Information for controlling the rovers can only be transmitted once a day because of the four and a half minute lag in the radio signal, which travels at the speed of light between Earth and Mars. Even though Earth and Mars are extremely close right now, it would be impossible to directly control the movement of the rovers because of this long lag in reaction time. Therefore, each movement that the rovers make must be intricately planned in advance.

The most exciting recent discoveries have involved the composition of rocks.

“The ‘rinds’ that form on the rocks at Meridiani – seem to have enrichments of NaCl in them, ordinary table salt,” said Prof. Steven Squyres Ph.D. ’78, astronomy. The presence of salt suggests the existence of a process involving water, which has implications for the existence of life on Mars. However, more data must be gathered and analyzed to fully understand this process.

The team has also discovered a new type of basalt at Gusev Crater “that may have been put into place after the Columbia Hills formed,” Squyres said. This discovery indicates that volcanic activity was not just restricted to the plains, but some lava was able to force its way to the surface through fractures in the hill materials. The Columbia Hills were named in honor of the astronauts who died in the Columbia accident.

Both rovers are in “excellent health,” Squyres said, “but they’re both so far past their 90-day ‘warranty’ now that there’s no reason to have any confidence in their continued health. They could last for another year, or they could drop dead tomorrow.”

Opportunity has been working around the western rim of the Erebus Crater. Erebus is the largest crater between Endurance Crater, which has already been explored, and Victoria Crater, which is where the rover is headed. However, because the terrain in Erebus Crater looks fairly unpleasant, the team is trying to find another route to reduce the amount of driving through the crater. It is important to study the rock in Erebus Crater in case the compositions of Endurance and Victoria Craters differ. “It will be valuable to have looked at some of the rocks in between,” Squyres said.

Spirit is currently on a precarious 27 degree perch on Hillary Hill. The team plans on having the rover back down off the perch to gather further information on Hillary, go down around Hillary into the Columbia Hills, specifically Husband Hill, and then study the Martian atmosphere. Because the mission has lasted much longer than estimated, the team is tired. They will continue the project as long as the rovers last, but when the rovers are no longer functioning, the team is “going to take a very long rest,” Squyres said. It is going to take years to analyze all of the data that has been accumulated.

Archived article by Dana Mendelowitz
Sun Contributor