NASA's Phoenix Mars Lander Puts Soil in Chemistry Lab, Team Discusses Next Steps

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Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
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Dwayne Brown 202-358-1726
NASA Headquarters, Washington
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Sara Hammond 520-626-1974
University of Arizona, Tucson
shammond@lpl.arizona.edu

NEWS RELEASE: 2008-120 June 25, 2008

NASA's Phoenix Mars Lander Puts Soil in Chemistry Lab, Team Discusses Next Steps

TUCSON, Ariz. -- NASA's Phoenix Mars Lander placed a sample of Martian soil in the
spacecraft's wet chemistry laboratory today for the first time. Results from that
instrument, part of Phoenix's Microscopy, Electrochemistry and Conductivity Analyzer,
are expected to provide the first measurement of the acidity or alkalinity of the planet's
soil.

The analysis of this soil sample and others will help researchers determine whether ice
beneath the soil ever has melted, and whether the soil has other qualities favorable for
life.

The Phoenix team is discussing what sample to deliver next to the lander's other
analytical instrument, which bakes and sniffs soil to identify volatile ingredients.
Engineers have identified possible problems in the mechanical and electrical operation of
that instrument, the Thermal and Evolved-Gas Analyzer, or TEGA.

Scientists are studying information provided by TEGA's analysis of the first Martian soil
sample put in that instrument. The instrument has eight single-use oven cells; each cell
can analyze one sample. When doors for a second TEGA oven were commanded open
last week, the doors opened only partway. Later, the team determined that mechanical
interference may prevent doors on that oven and three others from opening fully. The
remaining three ovens are expected to have one door that opens fully and one that opens
partially, as was the case with the first oven used.

"The tests we have done in our test facility during the past few days show the robotic arm
can deliver the simulated Martian soil through the opening with the doors in this
configuration," said William Boynton of the University of Arizona, Tucson, lead scientist
for TEGA. "We plan to save the cells where doors can open wider for accepting ice
samples."

Scientists believe the first soil sample delivered to TEGA was so clumpy that soil
particles clogged a screen over the opening. Four days of vibration eventually succeeded
at getting the soil through the screen. However, engineers believe the use of a motor to
create the vibration may also have caused a short circuit in wiring near that oven.
Concern about triggering other short circuits has prompted the Phoenix team to be
cautious about the use of other TEGA oven cells.

Subsequent soil samples for TEGA will be delivered with a different method than the
first. The new method will sprinkle soil into the instrument to make it easier for particles
to get through the screens.

The Phoenix mission is led by Peter Smith at the University of Arizona with project
management at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the
development partnership at Lockheed Martin in Denver. International contributions are
from the Canadian Space Agency; the University of Neuchatel, Switzerland; 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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