NASA's
Phoenix Mars Lander successfully scooped up a sample of Martian soil with its
robotic arm, mission scientists said on Friday.
The scoop
is poised and ready to deliver the sample to an instrument on the
spacecraft that will analyze the soil.
"This
is really an important occasion for us, to be poised to make a measurement for
the first time of the Martian arctic soil," said Phoenix principal
investigator Peter Smith of the University of Arizona.
The $420
million mission aims to dig down through the soil to the layers of water ice thought
to lie underneath the surface, and to analyze soil samples to determine their
composition and see if the ice might once have been liquid water, potentially
creating a habitable zone for microbial life at some point in the past.
Phoenix retrieved its sample Thursday from
a site dubbed Baby
Bear, which lies just to the right of the trench the lander dug out in its
practice digs. The practice digging locale is called Dodo. After scooping up
the sample, measuring about 1 cup in volume, Phoenix used its robotic arm
camera to photograph
the sample so that scientists could make sure they had enough to deliver to
the Thermal and Evolved-Gas Analyzer (TEGA) instrument aboard the lander.
"This
looks like a really good sample for us," Smith said.
Mission controllers will send instructions
to the lander to dump the sample into one of the TEGA ovens tonight. The TEGA
ovens, which are about an inch long and the diameter of a pencil lead, will
heat up the soil samples and use a mass spectrometer to detect the gases that
come off the samples, which will shed light on some of the materials in the
soil, specifically those formed by the process of liquid water.
"The
TEGA system is particularly sensitive to water in its oven ... water is the first
thing that's cooked out," Smith said.
Mission scientists must be careful when
delivering the sample not to overload the instrument and contaminate other
ovens. Once the sample is delivered on Friday, Phoenix will image TEGA to make
sure the sample has been delivered and that the oven door is shut. The
instrument is will then begin its four-day analysis (which may not occur in
four consecutive days); the team will report each day's results as they become
available. Any water present in the sample should be the first thing to
vaporize from the soil, Smith said.
The sample
also contains some of the white material seen in the scoop after Phoenix's first practice "dig and dump," which scientists think could be ice or a
type of salt mineral.
Of course,
they can't be sure that any of the white material will make it through the
oven's entry screen. "We're hoping that some of this goes in and that we
get a hint of what it is," Smith said.
Some
science team members think that the whitish material can't be ice because it
has been too easy to scrape up — the ice layers under the soil will likely be
difficult to scrap because ice is so hard at the brutally frigid temperatures
on Mars (which have so far reached a high of only -22 degrees Fahrenheit (-30
Celsius) since Phoenix
landed).
"Some
people think that it's too easy to get this material and that it can't be ice,"
Smith said. But he added that if the white material turns out to be some kind
of salt, "that would be a very nice discovery" because salts are what
is left when water reacts with soil.
After TEGA
begins its analysis, the lander will start digging up samples for its
microscopes and its wet chemistry lab. The microscope samples will likely be
taken from the same Baby Bear site as the TEGA samples, because they will she
further light on TEGA's results. The wet chemistry samples will be taken from
an adjacent site just to the right of Baby Bear, dubbed Mama Bear.
"If we
have a really good week [next week], we could have each of those delivered by
the end of the week," Smith said.
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