NASA's Phoenix Mars Lander to Begin Rasping Frozen Layer

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

Sara Hammond 520-626-1974
University of Arizona, Tucson
shammond@lpl.arizona.edu

NEWS RELEASE: 2008-133 July 15, 2008

NASA's Phoenix Mars Lander to Begin Rasping Frozen Layer

TUCSON, Ariz. -- A powered rasp on the back of the robotic arm scoop of NASA's
Phoenix Mars Lander is being tested for the first time on Mars in gathering sample
shavings of ice.

The lander has used its arm in recent days to clear away loose soil from a subsurface
layer of hard-frozen material and create a large enough area to use the motorized rasp in a
trench informally named "Snow White."

The Phoenix team prepared commands early Tuesday for beginning a series of tests with
the rasp later in the day. Engineers and scientists designed the tests to lead up to, in
coming days, delivering a sample of icy soil into one of the lander's laboratory ovens.

"While Phoenix was in development, we added the rasp to the robotic arm design
specifically to grind into very hard surface ice," said Barry Goldstein, Phoenix project
manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This is the exactly the
situation we find we are facing on Mars, so we believe we have the right tool for the job.
Honeybee Robotics in New York City did a heroic job of designing and delivering the
rasp on a very short schedule."

The rasp bit extends at a shallow angle out of an opening on the back of the scoop at the
end of the 2.35-meter-long (7.7-foot-long) robotic arm. To use it, the back surface of the
scoop is placed on the ground, and a motor rotates the rasp. The angle of the rasp is
increased from nearly horizontal to slightly steeper while it is rotating, so the tool kicks
shavings sideways onto a collection surface just inside the opening. After the rasp stops, a
series of moves by the scoop then shifts the collected shavings from the back of the
scoop, past baffles, to the front of the scoop. The baffles serve to keep material from
falling out of the rasp opening when the scoop is used as a front loader.

The commands prepared for Phoenix's activities Tuesday called for rasping into the hard
material at the bottom of the Snow White trench at two points about one centimeter (0.4
inch) apart. The lander's Surface Stereo Imager and robotic arm camera will be used to
check the process at several steps and to monitor any resulting sample in the scoop for
several hours after it is collected.

Collecting an icy sample for an oven of Phoenix's Thermal and Evolved-Gas Analyzer
(TEGA) may involve gathering shavings collected at the rasp opening and scooping up
additional shavings produced by the rasp. The Phoenix team has been testing this
combination on simulated Martian ice with a near-replica model of Phoenix in a test
facility at the University of Arizona, Tucson.

The Phoenix mission is led by Peter Smith of the University of Arizona with project
management at JPL and development partnership at Lockheed Martin, Denver.
International contributions come from the Canadian Space Agency; the University of
Neuchatel; the universities of Copenhagen and Aarhus, Denmark; Max Planck Institute,
Germany; and the Finnish Meteorological Institute. For more about Phoenix, visit:

http://www.nasa.gov/phoenix and http://phoenix.lpl.arizona.edu.

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