NASA: Martian soil may be more alien than first thought

Initial tests showed asparagus would grow on Mars, but now space garden may be out

New test results coming in from the Phoenix Mars Lander suggest that Martian soil may not be so akin to Earth's after all.

A little over a month after NASA scientists announced that they were finding more familiar elements than alien ones in the soil on Mars from test results sent back by the Lander, researchers now have discovered evidence that that might not be the case after all. They're also double-checking to make sure that the Earth-like elements found by Phoenix on the northern pole of Mars weren't actually brought from Earth and deposited there when the Lander touched down.

"We are committed to following a rigorous scientific process. While we have not completed our process on these soil samples, we have very interesting intermediate results," Peter Smith, Phoenix's principal investigator, said in a written statement released today. Smith, who is a senior research scientist at the University of Arizona, added that while the initial analyses from the wet chemistry laboratory onboard Phoenix suggested that Martian soil was like that of Earth, "further analysis has revealed un-Earthlike aspects of the soil chemistry."

NASA planned to hold a press conference at 2 p.m. EDT today to discuss the findings from the Mars research. In information sent out prior to the press conference, NASA noted that previous tests, including one done in the wet chemistry lab on Phoenix, showed the presence of perchlorate, which is described as a highly oxidizing substance. However, this week, the analysis ovens onboard the Lander sent back new information showing that no evidence of perchlorate was found in a sample taken directly above the ice layer on Mars.

Perchlorate can be found on Earth as both a natural and a manmade contaminant. According to the California Department of Toxic Substances Control, the compound is used as an ingredient in solid fuel for rockets and missiles. Perchlorate-based chemicals also are used to build fireworks, pyrotechnics and explosives. "Perchlorate is becoming a serious threat to human health and water resources," the department says on its Web site.

NASA scientists are working to figure out if the Mars Lander could have contaminated the testing area when it landed, or if Phoenix's testing instruments could have contained biological contaminants. "When surprising results are found, we want to review and ensure our extensive prelaunch contamination-control processes covered this potential," Barry Goldstein, the Phoenix mission's project manager, said in a statement.

In late June, after scientists received the first test results from the wet chemistry lab on the Lander, Samuel Kounaves, a Tufts University professor and a research affiliate at NASA's Jet Propulsion Laboratory, said that they "were all very flabbergasted at the data we got back." Phoenix is using a robotic arm to dig a shallow trench and then scoop up and analyze soil samples on the northern pole of Mars, and Kounaves said that the preliminary findings showed the presence of minerals that are essential to life."

"We basically have found what appears to be the requirements to support life, whether in the past, present or future," he said then. "We have elements that you might find in your backyard."

For instance, the soil was very alkaline, with a pH level of between 8 and 9, according to the initial data sent back by the Lander. The first tests also found magnesium, sodium, potassium and chloride in the Martian soil. "Some kinds of Earth life would be happy to live in these soils," Kounaves said in June. "Asparagus, green beans and turnips love alkaline soils."

Now, however, the question of whether the soil on Mars really is Earth-like appears to again be a bone of contention.

Copyright © 2008 IDG Communications, Inc.

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