NASA scientists, hoping to quell a growing number of rumors, say it's way to early to say exactly what they've found in the Martian soil.
In June, researchers at NASA and the Jet Propulsion Laboratory announced that they were finding more familiar than alien elements in the soil on Mars from initial test results sent back by the analysis equipment onboard the Mars Lander. Then this past weekend, rumors and posts started to appear on the Internet claiming that scientists had found a toxic chemical that would make the Red Planet uninhabitable.
Noting that they were stepping outside their normal scientific process, NASA assembled a team of Mars mission scientists Tuesday afternoon for a press conference aimed at tackling the rumors. Duane Brown, a NASA spokesman, said they wanted to address rumors that NASA had been withholding information from the public about a major finding.
Peter Smith, Phoenix's principal investigator, said there has been some evidence of the presence of perchlorate, which is described as a highly oxidizing substance.
"This is an important piece in the puzzle as we strive to determine if a habitable environment exists on Mars," said Smith. "It is neither good nor bad for life... It does not preclude life on Mars. In fact, it's a potential energy source."
Dr. Michael Meyer, lead scientist for NASA's Mars Exploration Program, said he does not regret the summer's earlier announcement that they had found Earth-like elements in the Martian soil and that their initial analysis found that Martian soil could support life.
"Some kinds of Earth life would be happy to live in these soils," Samuel Kounaves, a Tufts University professor and a research affiliate at NASA's Jet Propulsion Laboratory, said in June. "Asparagus, green beans and turnips love alkaline soils."
The presence of perchlorate, however, raises new questions.
Perchlorate can be found on Earth as both a natural and a man-made 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.
Smith said they are investigating but he doesn't think of contamination as much of a possibility.
"We must be sure we have not introduced the material," he added. "I must say it seems rather remote since our fuel is hydrazine and contains no chlorine. It could have migrated in the spacecraft before leaving Earth but that's a low possibility.
Richard Quinn, a research scientist with NASA, said perchlorate is not a life-killer. He noted that some microbes co-exist with it quite easily and others actually use it as a life source.
So where did the confusion about the presence of perchlorate come from?
Well, scientists got different findings from different testing instruments.
Scientists explained today that the first oven analysis showed signs of oxygen, which would be consistent with perchlorate, but it did not show any signs of chlorine, which would be another indicator of perchlorate. However, the wet chemistry test did find evidence of perchlorate.
One reason for the different findings simply could lay with the fact that the oven analysis wasn't looking for chlorine or perchlorate.
"During the [oven] analysis, they didn't look for chlorine since they were not expecting it," said Bill Boynton, a co-investigator on the Mars mission.
Boynton, though, also said a second oven analysis also showed no signs of perchlorate. That could have been because the perchlorate wasn't in the sample area or that some perchlorates simply don't give off chlorine when heated.
At this point, researchers will be running more wet chemistry and oven analyses and then will be sorting through their findings. With a recent extension to the mission, they're only halfway through their research on the Martian north pole.
"We don't want to come to the media and say we found chocolate on Mars and then two weeks later say we were wrong, it's strawberry," Michael Hecht, a co-investigator on the Mars mission, said at the press conference. "That makes us look bad and it makes you look bad."