New Prototype of the Mars Organic Analyzer (MOA)
“I admit I never actually wrote this goal into my grant,” UC Berkeley Professor of Chemistry Richard Mathies told me, as one of his graduate students injected a drop of Zinfandel into Mathies’s organic analyzer. “But it is an important demonstration” that the detector actually works.
The Mars Organic Analyzer has been chosen by NASA to be included in the Urey instrument that will eventually fly aboard the European Space Agency’s ExoMars rover in 2013. The first taken step has been by Richard Mathies, UC Berkeley Professor of Chemistry, to bring forth a prototype device to be included in one of the most sophisticated life-detection instruments that has even been sent to Mars. Hopefully, it will be able to answer the Martian questions which were never answered by the Viking Landers over 30-years ago.
Possible answers may be found this time, as the MOA is taking an entirely different approach to analyze the soil samples taken from Mars, than the Viking Landers did. The landers had ovens which burned the Martian soil with special instruments that would pick up odors of the escaping organic compounds—but none were found. Today’s researchers and scientists feel that even if there had been organic compounds in the soil during that time, none would have been found due to the type of approach being used.
A liquid process that will look primarily for nitrogen-based compounds, known as amines, will be used aboard the MOA. The reason for this is because amines are in the majority of life’s molecules. “Eighty to ninety percent of the dry weight of a bacterial cell is amines of various forms, mostly amino acids,” says Mathies. According to Mathies, the first two steps of the process are to prepare the sample for analysis:
** FIRST STEP—The sample is steamed with a very-high temperature and high-pressure water, in order to extract the organic material. This is similar to an expresso machine process.
** SECOND STEP – This is referred to as “tagging” which marks the amine-containing molecules for detection, where the slurry from step one is mixed with a fluorescent dye. IF the sample contains amines, the dye will attach itself to them.
**FOLLOWING STEPS – The tagged sample is injected into the MOA, which is a circular glass disk, four inches in diameter and a laser. Etched into the glass disk is a long, narrow channel the width of a human hair, which moves and “snakes” back and forth through the disk’s interior.
Once the electric field is applied to the liquid in this channel, a separation occurs within the various compounds, with positive ions going one direction—and negative ions going another—with smaller molecules much faster moving than the large ones. After just a few minutes, the sample’s contents are placed along the channel in a predictable order. As the tagged molecules are pushed past tiny laser from this channel, the light will cause them to give off light at a different frequency than of the laser. This secondary light is what the detector will measure, with Mathies recognizing the specific molecule that is present when a fluorescent response occurring, and the strength of the response telling of its amount available.
This entry was posted on Wednesday, March 19th, 2008 at 8:39 am and is filed under Space Agency News, The Gear to Get There. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
