Phoenix Mars Team Opens Window on Scientific Process

Aug 06, 2008
This image was acquired by Phoenix on July 8, 2008. This image shows the trench informally called "Snow White." Two samples were delivered to the Wet Chemistry Laboratory, which is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer (MECA). Image credit: NASA/JPL-Calech/University of Arizona

(PhysOrg.com) -- Phoenix Mars mission scientists spoke today on research in progress concerning an ongoing investigation of perchlorate salts detected in soil analyzed by the wet chemistry laboratory aboard NASA's Phoenix Lander.

"Finding perchlorates is neither good nor bad for life, but it does make us reassess how we think about life on Mars," said Michael Hecht of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead scientist for the Microscopy, Electrochemistry and Conductivity Analyzer (MECA), the instrument that includes the wet chemistry laboratory.

If confirmed, the result is exciting, Hecht said, "because different types of perchlorate salts have interesting properties that may bear on the way things work on Mars if -- and that's a big 'if ' -- the results from our two teaspoons of soil are representative of all of Mars, or at least a significant portion of the planet."

The Phoenix team had wanted to check the finding with another lander instrument, the Thermal and Evolved-Gas Analyzer (TEGA), which heats soil and analyzes gases driven off. But as that TEGA experiment was underway last week, speculative news reports surfaced claiming the team was holding back a major finding regarding habitability on Mars.

"The Phoenix project has decided to take an unusual step" in talking about the research when its scientists are only about half-way through the data collection phase and have not yet had time to complete data analysis or perform needed laboratory work, said Phoenix principal investigator Peter Smith of the University of Arizona, Tucson. Scientists are still at the stage where they are examining multiple hypotheses, given evidence that the soil contains perchlorate.

"We decided to show the public science in action because of the extreme interest in the Phoenix mission, which is searching for a habitable environment on the northern plains of Mars," Smith added. "Right now, we don't know whether finding perchlorate is good news or bad news for possible life on Mars."

Perchlorate is an ion, or charged particle, that consists of an atom of chlorine surrounded by four oxygen atoms. It is an oxidant, that is, it can release oxygen, but it is not a powerful one. Perchlorates are found naturally on Earth at such places as Chile's hyper-arid Atacama Desert. The compounds are quite stable and do not destroy organic material under normal circumstances. Some microorganisms on Earth are fueled by processes that involve perchlorates, and some plants concentrate the substance. Perchlorates are also used in rocket fuel and fireworks.

Perchlorate was discovered with a multi-use sensor that detects perchlorate, nitrate and other ions. The MECA team saw the perchlorate signal in a sample taken from the Dodo-Goldilocks trench on June 25, or Sol 30, or the 30th Martian day of the mission after landing, and again in another sample taken from the Snow White trench on July 6, or Sol 41.

When TEGA heated a sample of soil dug from the Dodo-Goldilocks trench on Sol 25 to high temperature, it detected an oxygen release, said TEGA lead scientist William Boynton of the University of Arizona. Perchlorate could be one of several possible sources of this oxygen, he said.

Late last week, when TEGA analyzed another sample, this one from the Snow White trench, the TEGA team looked for chlorine gas. The instrument detected none.

"Had we seen it, the identification of perchlorate would be absolutely clear, but in this run we did not see any chlorine gas. We may have been analyzing a perchlorate salt that doesn't release chlorine gas upon heating," Boynton said. "There's nothing in the TEGA data that contradicts MECA's finding of perchlorates."

As the Phoenix team continues its investigation of the artic soil, the TEGA instrument will attempt to validate the perchlorate discovery and determine its concentration and properties.

Provided by NASA

Explore further: Space station's 3-D printer pops out 1st creation

add to favorites email to friend print save as pdf

Related Stories

Martian soil may contain detrimental substance

Aug 05, 2008

Scientists are analyzing results from soil samples delivered several weeks ago to science instruments on NASA's Phoenix Mars Lander to understand the landing site's soil chemistry and mineralogy.

Recommended for you

Iridium flares captured in real time by astrophotographer

7 hours ago

There are so many fun sights to see in the sky that are pure astronomical magic. And then there are the spectacular human-created sights. One of those sights is watching satellites from the Iridium constellation ...

Is Phobos doomed?

8 hours ago

"All these worlds are yours except Europa, attempt no landing there."

Espresso in space

10 hours ago

Espresso-loving astronauts, rejoice! You may soon be able to enjoy your beloved beverage in space, thanks to a new cup designed specifically to defy the low-gravity environments encountered aboard the International ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

out7x
1 / 5 (1) Aug 08, 2008
How does MECA distinguish SO4 ions from ClO4 ?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.