Phoenix Still Analyzing Martian Soil Data
Despite reports last week by a noted aerospace trade journal --
suggesting NASA was very close to revealing that findings from the
Phoenix Mars Lander indicated ideal conditions to support
carbon-based life -- on Monday the agency said while the final
verdict is still out, no one should hold their breath for such an
Instead, NASA says its scientists are still analyzing results
from soil samples delivered several weeks ago to science
instruments on NASA's Phoenix Mars Lander to understand the landing
site's soil chemistry and mineralogy.
Within the last month, two samples have been analyzed by the Wet
Chemistry Lab of the spacecraft's Microscopy, Electrochemistry, and
Conductivity Analyzer, or MECA, suggesting one of the soil
constituents may be perchlorate, a highly oxidizing substance. The
Phoenix team has been waiting for complementary results from the
Thermal and Evolved-Gas Analyzer, or TEGA, which also is capable of
detecting perchlorate. TEGA is a series of ovens and analyzers that
"sniff" vapors released from substances in a sample.
Confirmation of the presence of perchlorate and supporting data
is important prior to scientific peer review and subsequent public
announcements. The results from Sunday's TEGA experiment, which
analyzed a sample taken directly above the ice layer, found no
evidence of this compound.
"This is surprising since an earlier TEGA measurement of surface
materials was consistent with but not conclusive of the presence of
perchlorate," said Peter Smith, Phoenix's principal investigator at
the University of Arizona, Tucson.
Scientists at the Phoenix Science Operations Center at the
University of Arizona are specifically looking at the data from
these instruments to provide information on the composition of
"We are committed to following a rigorous scientific process.
While we have not completed our process on these soil samples, we
have very interesting intermediate results," said Smith, "Initial
MECA analyses suggested Earth-like soil. Further analysis has
revealed un-Earthlike aspects of the soil chemistry."
The team also is working to totally exonerate any possibility of
the perchlorate readings being influenced by terrestrial sources
which may have migrated from the spacecraft, either into samples or
into the instrumentation.
"When surprising results are found, we want to review and assure
our extensive pre-launch contamination control processes covered
this potential," said Barry Goldstein, Phoenix project manager at
NASA's Jet Propulsion Laboratory in Pasadena, CA.
Since landing on May 25, Phoenix has been studying Martian soil
with MECA's wet chemistry lab, two microscopes and a conductivity
probe, TEGA's ovens and two cameras.
MECA's robotic wet chemistry lab studies soluble chemicals in
the soil by mixing a soil sample with a water-based solution with
several reagents brought from Earth. The inner surface of each
cell's beaker has 26 sensors that give information about the
acidity or alkalinity and concentrations of elements such as
chloride or perchlorate. The beaker also can detect concentrations
of magnesium, calcium and potassium, which form salts that are
soluble in water.
With continuing results and the spacecraft in good condition,
the mission has been extended through September 30. The original
prime mission of three months ends in late August. The mission
extension adds five weeks to the 90 days of the prime mission.