Mid-Depth Soil Collected for Lab Test On Phoenix Mars Lander

http://www.jpl.nasa.gov/news/news.cfm?release=2008-163

Mid-Depth Soil Collected for Lab Test On NASA's Mars Lander
Jet Propulsion Laboratory
August 21, 2008

TUCSON, Ariz. -- NASA's Phoenix Mars Lander has scooped up a soil
sample
from an intermediate depth between the ground surface and a subsurface
icy layer. The sample was delivered to a laboratory oven on the
spacecraft.

The robotic arm on Phoenix collected the sample, dubbed "Burning
Coals,"
from a trench named "Burn Alive 3." The sample consisted of about
one-fourth to one-half teaspoon of loose soil scooped from depth about
3
centimeters (1.2 inch) below the surface of the ground and about 1
centimeter (0.4 inch) above a hard, icy underground layer.

Data received from Phoenix early Thursday confirmed that the arm had
delivered some of that sample through the doors of cell 7 on the
lander's Thermal and Evolved Gas Analyzer (TEGA) and that enough
material passed through a screen and down a funnel to nearly fill the
cell's tiny oven. The Phoenix team prepared commands Thursday to have
TEGA close the oven and begin heating the sample to low temperature
(35
degrees Celsius, or 95 degrees Fahrenheit).

The purpose of the low temperature heating is to look for ice in the
sample. The next step is a middle temperature process, which heats the
sample to 125 degrees Celsius (257 degrees Fahrenheit) to thoroughly
dry
the sample. The last heating takes the sample to 1000 degrees Celsius
(1832 degrees Fahrenheit). The gases given off during these heating
stages help the science team to determine properties of the Martian
soil.

"We are expecting the sample to look similar to previous samples,"
said
William Boynton of the University of Arizona, lead scientist for TEGA.
"One of the things we'll be looking for is an oxygen release
indicative
of perchlorate."

Perchlorate was found in a sample delivered to Phoenix's Microscopy,
Electrochemistry, and Conductivity Analyzer (MECA). The MECA team saw
the perchlorate signal in a sample taken from a trench called
"Dodo-Goldilocks" on June 25, and again in another sample taken from
the
"Rosy Red" trench on July 6. To see signs of perchlorate in TEGA would
help confirm the previous results. Scientists are analyzing data from
a
Rosy Red surface sample heated in TEGA cell number 5 last week.

The new sample in cell 7 completes a three-level soil profile that
also
includes the surface material (from Rosy Red) and ice-layer material
(from a trench called "Snow White").

"We want to know the structure and composition of the soil at the
surface, at the ice and in-between to help answer questions about the
movement of water -- either as vapor or liquid -- between the icy
layer
and the surface," said Ray Arvidson of Washington University in St.
Louis, a leader of Phoenix science team activities.

The Phoenix mission is led by Peter Smith of The University of Arizona
with project management at the Jet Propulsion Laboratory and
development
partnership at Lockheed Martin, located in 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.

------------------------------------------------------------------------

Media contacts: Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@xxxxxxxxxxxx

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

2008-163
.

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