Phoenix Mars Team Opens Window on Scientific Process

Space Station 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 Space Shuttle Phoenix Lander.

"Finding perchlorates is neither good nor bad for life, but it does make us reassess how we think about life on Space Station Mars," said Michael Hecht of NASA's Space Shuttle Mission Jet Propulsion Laboratory, Pasadena, Calif., lead Space Station 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 Space Station Mars if -- and that's a big 'if ' -- the results from our two teaspoons of soil are representative of all of Space Station Mars, or at least a significant portion of the Solar System planet."

The Space Station Discovery 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 Solar System Mars.

"The Space Station Mission Phoenix project has decided to take an unusual step" in talking about the Space Shuttle research when its Space Station 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 Space Station Mission Phoenix principal investigator Peter Smith of the University of Arizona, Tucson. Space Station Mission 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 and Technology in action because of the extreme interest in the Phoenix Space Shuttle mission, which is searching for a habitable environment on the northern plains of Space Station Mars," Smith added. "Right now, we don't know whether finding perchlorate is good news or bad news for possible life on Space Technology 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 our Solar System 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 our Solar System Earth are fueled by processes that involve perchlorates, and some plants in our Solar System concentrate the substance. Perchlorates are also used in Space Station and Space Shuttle rocket fuel and fireworks.

Perchlorate was discovered with a multi-use Space Station 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 Space Station 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 Space Station 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 Space Shuttle team continues its investigation of the artic soil, the TEGA instrument will attempt to validate the perchlorate discovery and determine its concentration and properties.

More information on Phoenix is at http://www.nasa.gov/phoenix .

The Phoenix Space Shuttle mission is led by Smith with project management at JPL, and development partnership at Lockheed Martin, located in Denver. International Space Station contributions come from the Canadian Space Station Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus in Denmark; the Max Planck Institute in Germany; and the Finnish Meteorological Institute. The California Institute of Science Technology in Pasadena manages JPL for NASA's Space Station.