NASA's Phoenix Mars Lander Uses Soil Probe and Swiss Scope

Guy Webster 818-354-5011
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

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

J.D. Harrington 202-358-5241
NASA Headquarters, Washington
j.d.harrington@nasa.gov

News release: 2008-130 July 10, 2008

NASA's Phoenix Mars Lander Uses Soil Probe and Swiss Scope

NASA's Phoenix Mars Lander has touched Martian soil with a fork-like probe for the first time and begun using
a microscope that examines shapes of tiny particles by touching them.

Phoenix's robotic arm pushed the fork-like probe's four spikes into undisturbed soil Tuesday as a validation
test of the insertion procedure. The prongs of this thermal and electrical conductivity probe are about 1.5
centimeters, or half an inch, long. The science team will use the probe tool to assess how easily heat and
electricity move through the soil from one spike to another. Such measurements can provide information about
frozen or unfrozen water in the soil.

The probe sits on a "knuckle" of the 2.35-meter-long (7.7-foot-long) robotic arm. Held up in the air, it has
provided assessments of water vapor in the atmosphere several times since Phoenix's May 25 landing on far-
northern Mars. Researchers anticipate getting the probe's first soil measurements following a second
placement into the ground, planned as part of today's Phoenix activities on Mars.

Phoenix also has returned the first image from its atomic force microscope. This Swiss-made microscope
builds an image of the surface of a particle by sensing it with a sharp tip at the end of a spring, all
microfabricated from a sliver of silicon. The sensor rides up and down following the contour of the surface,
providing information about the target's shape.

"The same day we first touched a target with the thermal and electrical conductivity probe, we first touched
another target with a needle about three orders of magnitude smaller -- one of the tips of our atomic force
microscope," said Michael Hecht of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead scientist for the
suite of instruments on Phoenix that includes both the conductivity probe and the microscopy station.

The atomic force microscope can provide details of soil-particle shapes as small as about 100 nanometers,
less than one-hundredth the width of a human hair. This is about 20 times smaller than what can be resolved
with Phoenix's optical microscope, which has provided much higher-magnification imaging than anything seen
on Mars previously.

The first touch of an atomic force microscope tip to a substrate on the microscopy station's sample-
presentation wheel served as a validation test. The substrate will be used to hold soil particles in place for
inspection by the microscope. The microscope's first imaging began Wednesday and produced a calibration
image of a grooved substrate. "It's just amazing when you think that the entire area in this image fits on an
eyelash. I'm looking forward to exciting things to come," Hecht said.

With these developments in the past two days, the spacecraft has put to use all the capabilities of its
Microscopy, Electrochemistry and Conductivity Analyzer, or MECA, suite of instruments. Researchers have
begun analyzing data this week from the second sample of soil tested by MECA's wet chemistry laboratory.

Meanwhile, the Phoenix team is checking for the best method to gather a sample of Martian ice to analyze
using the lander's Thermal and Evolved-Gas Analyzer, which heats samples and identifies vapors from them.
Researchers are using Phoenix's robotic arm to clear off a patch of hard material uncovered in a shallow
trench informally called "Snow White." They plan in coming days to begin using a motorized rasp on the back
of the arm's scoop to loosen bits of the hard material, which is expected to be rich in frozen water.

The atomic force microscope for Phoenix was provided by a consortium led by the University of Neuchatel,
Switzerland.

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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