TUCSON,
Ariz. – NASA's Phoenix Mars Lander sent back images of the blind spot
underneath it today as mission scientists gear up for the craft's robotic arm
to touch the planet's soil for the first time. The spacecraft also encountered
its first glitch, with a short circuit in one of its instruments, mission
scientists said at a briefing on Friday.
Phoenix's
robotic arm was maneuvered so that the camera at the end of it could image the space
underneath the lander, which is a blind spot for the stereo camera on top
of the lander's deck. The images showed some interesting tabular formations, as
robotic arm co-investigator Ray Arvidson, of Washtington University in St.
Louis, described them.
"We
don't know what they are. They could be exposures of ice, or they could be
exposures of rocks," Arvidson said at a briefing here at the University of
Arizona. "We're really pushing for ice, but we don't know if that's the case
yet."
The
$420 million dollar Phoenix mission is designed to
dig down to the layers of water ice thought to lie just under the surface
of the north polar region of Mars, where it landed on Sunday. Instruments on
the spacecraft are designed to analyze soil samples to see if the ice was once
liquid and could have created a habitable zone for possible microbial life at
some point in Mars' past.
Mission
controllers have encountered a problem with one of these instruments, the
Thermal and Evolved-Gas Analyzer (TEGA) that is designed to heat up soil
samples until vapors come off and then to analyze those vapors to detect
the composition of the soil.
The
glitch seems to be a short circuit in a filament in a part of the instrument
that ionizes the vapors before they are sent to the detector, said TEGA
co-investigator William Boynton of the University of Arizona. There are two
filaments in the detector however, and TEGA scientists are now investigating
whether they can operate the instrument with just the one filament. They will
also being sending up diagnostic instructions over the next few days.
"We're
quite optimistic that we have a workaround that will let us operate the
instrument," Boynton said.
Meanwhile,
mission scientists are also looking for more information on the soil near the
lander so that they can begin digging for samples. The first step will be
imaging all three of the landers' footpads with the robotic arm camera to make
sure the craft is stable on the ground, mission scientists said.
After
that, mission scientists plan to perform a "soil touch," which
involves moving the scoop at the end of the robotic arm and making a dent in
the soil, then turning the scoop around and imaging the dent to make sure that
controllers know how to reach the soil, Arvidson told SPACE.com.
The
next step will be to do what mission scientists call a "dig and dump"
where they will practice having the robotic arm scoop up the soil and dump it
down again.
Mission
controllers are waiting to get data back from Phoenix's Friday night downlink
on one of the proposed "dig and dump" sites to decide when and where to perform
the soil touch maneuver.
Click
here for SPACE.com's
Phoenix mission coverage and a link
to NASA TV.
advertisement
