mercredi 14 novembre 2012

Rover's 'SAM' Lab Instrument Suite Tastes Soil












NASA - Mars Science Laboratory (MSL) patch.

Nov. 14, 2012

A pinch of fine sand and dust became the first solid Martian sample deposited into the biggest instrument on NASA's Mars rover Curiosity: the Sample Analysis at Mars, or SAM.

Located inside the rover, SAM examines the chemistry of samples it ingests, checking particularly for chemistry relevant to whether an environment can support life. Curiosity's robotic arm delivered SAM's first taste of Martian soil to an inlet port on the rover deck on Nov. 9. During the following two days, SAM used mass spectrometry, gas chromatography and laser spectrometry to analyze the sample.

The sample came from the patch of windblown material called "Rocknest," which had provided a sample previously for mineralogical analysis by Curiosity's Chemistry and Mineralogy (CheMin) instrument. CheMin also received a new sample from the same Rocknest scoop that fed SAM. SAM has previously analyzed samples of the Martian atmosphere.


Image above: This subframe image from the left Mast Camera (Mastcam) on NASA's Mars rover Curiosity shows the covers in place over two sample inlet funnels of the rover's Sample Analysis at Mars (SAM) instrument suite. Image credit: NASA/JPL-Caltech/MSSS.

"We received good data from this first solid sample," said SAM Principal Investigator Paul Mahaffy of NASA Goddard Space Flight Center, Greenbelt, Md. "We have a lot of data analysis to do, and we are planning to get additional samples of Rocknest material to add confidence about what we learn."

The SAM Suite


Images above: The Sample Analysis at Mars (SAM) instrument, largest of the 10 science instruments for NASA's Mars Science Laboratory mission, examines samples of Martian rocks, soil and atmosphere for information about chemicals that are important to life and other chemical indicators about past and present environments.

SAM is in fact a suite of three different instruments supported by a complex set of components to process gases and solids. The instruments are: Quadrupole Mass Spectrometer (QMS), Tunable Laser Spectrometer (TLS), and Gas Chromatograph (GC).

Other components include: a sample manipulation system (SMS) with 74 cups; two solid sample inlet tubes (SSIT); two turbomolecular wide-range pumps (WRP); two ovens to release gas to SAM's instruments; 14 gas processing manifolds; two high conductance valves; 52 micro-valves; 51 gas line heaters; combustion and calibration gases; two scrubbers and two getters; four hydrocarbon traps; two helium tanks; four reflux heat pipes; an electronics stack consisting of eight separate modules; about 20 feet (600 meters) of harness wire; two gas inlets; and two vents to Curiosity's exterior.

The SAM instrument was developed at NASA Goddard Space Flight Center, Greenbelt, Md., with instrument contributions from NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the University of Paris, France, collaborators. Image credit: NASA/JPL-Caltech.

Potential Sources and Sinks of Methane on Mars


Illustration above: If the atmosphere of Mars contains methane, various possibilities have been proposed for where the methane could come from and how it could disappear.

Potential non-biological sources for methane on Mars include comets, degradation of interplanetary dust particles by ultraviolet light, and interaction between water and rock. A potential biological source would be microbes, if microbes have ever lived on Mars. Potential sinks for removing methane from the atmosphere are photochemistry in the atmosphere and loss of methane to the surface. Image credit: NASA/JPL-Caltech, SAM/GSFC.

Volatiles on Mars


This illustration shows the locations and interactions of volatiles on Mars. Volatiles are molecules that readily evaporate, converting to their gaseous form, such as water and carbon dioxide. On Mars, and other planets, these molecules are released from the crust and planetary interior into the atmosphere via volcanic plumes. On Mars, significant amounts of carbon dioxide go back and forth between polar ice caps and the atmosphere depending on the season (when it's colder, this gas freezes into the polar ice caps).

New results from the Sample Analysis at Mars, or SAM, instrument on NASA's Curiosity rover show that the lighter forms of certain volatiles, also called isotopes, have preferentially escaped from the atmosphere, leaving behind a larger proportion of heavy isotopes. Scientists will continue to examine this phenomenon as the mission continues, looking for isotope signatures in rocks. One question they plan to address is: To what degree have atmospheric volatiles been incorporated into rocks in the crust through the action of fluids, perhaps in the distant past? Image credit: NASA/JPL-Caltech.


Image above: High-Resolution Self-Portrait by Curiosity Rover Arm Camera. Image Credit: NASA/JPL-Caltech/Malin Space Science Systems.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the rover.

More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity .

Images (mentioned), Text, Credits: NASA / Jet Propulsion Laboratory / Guy Webster.

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