[meteorite-list] NASA's Phoenix Mars Lander Ready to Gather Samples

[Ron Baalke]

http://www.jpl.nasa.gov/news/phoenix/release.php?ArticleID=1731

NASA's Phoenix Mars Lander Ready to Gather Samples
Jet Propulsion Laboratory
June 04, 2008

TUCSON, Ariz. -- Two practice rounds of digging and dumping the clumpy
soil at the Martian arctic site this week gave scientists and engineers
gathered at the University of Arizona confidence to begin using
Phoenix's Robotic Arm to deliver soil samples to instruments on the
lander deck.

Those samples will not be collected before Thursday. Following
Wednesday's briefing on the mission, the Phoenix team learned that
NASA's Odyssey orbiter, which relays Phoenix data to and from Earth, had
entered a "safe mode," preventing Wednesday's (or sol 10) instructions
from reaching the lander. Instead, Phoenix will complete a sequence of
commands that are already stored on board. That sequence includes
instructions for the lander to continue taking images required to
assemble a full-color 360-degree high-resolution panorama.

Odyssey mission managers are doing a check out of the orbiter to
determine what triggered the safe mode. During safe mode, the spacecraft
turns off non-essential operations and waits for instructions from
Earth. In the meantime, the Phoenix team has been directed to issue
commands to the lander and receive data through Mars Reconnaissance
Orbiter (MRO). While Phoenix has been primarily utilizing Odyssey for
relay services since MRO's UHF radio unexpectedly powered off during a
relay pass on Sol 2, the radio has been exercised repeatedly over the
past week and appears to be operating well.

The two practice digs have already enticed scientists about some bright
material in the soil just beneath the surface.

"Two scoops into the soil we see there's a white layer becoming visible
in the wall of the trench," said Carol Stoker of NASA Ames Research
Center, Moffett Field, Calif., a member of the Phoenix science team.

Phoenix Principal Investigator Peter Smith said, "We've had an
impassioned discussion of whether that may be salts or ice or some other
material even more exotic."

Concentrations of salts can be indicators of formerly wet conditions.
One goal for the Phoenix mission is to determine whether the ice beneath
the surface of far-northern Mars ever thaws during long-term climate
cycles.

The location chosen for the sample is adjacent to the hole dug by the
two practice scoops. The team plans to command the arm to deliver the
sample to the lander's Thermal and Evolved-Gas Analyzer (TEGA), after it
first receives images to confirm that the scoop holds collected soil
ready for delivery.

"The arm has been performing flawlessly," said Ashitey Trebi-Ollennu of
NASA's Jet Propulsion Laboratory, senior robotics engineer on the
Phoenix Robotic Arm team. The arm made daring, Tai Chi or Yoga-like
moves to position the Robotic Arm Camera to take pictures underneath the
lander, and did its two test digs "magnificently," he said.

Phoenix is the first mission to dig into Mars with a robotic arm since
the Viking landers in the 1970s.

"We have only dug to a depth of an inch or two, so we know there are
challenges ahead," Trebi-Ollennu added. "But we are confident that we'll
get a good amount of material to deliver to TEGA."

In addition to the bright material seen where the arm collected test
samples, a layer of hard, light-toned substrate has been seen in images
taken underneath the lander by the Robotic Arm Camera.

"We think the lander is sitting on a layer of this white material that
possibly extends beyond, out into our work area," said Uwe Keller,
Robotic Arm Camera lead scientist from the Max Planck Institute for
Solar System Research, Katlenburg-Lindau, Germany. Phoenix's telltale,
which is part of the Canadian Space Agency's meteorological package and
the highest part of the lander, has proved to be very sensitive to
Martian winds, said Haraldur Gunnlaugsson of the University of Aarhus,
Denmark, which provided the device.

"A storm on Mars is a gentle hand movement on Earth," Gunnlaugsson said.
Surface Stereo Imager images of the telltale show a diurnal pattern to
Martian winds. Winds come from the south in the morning, blow in from
the north by mid-day, from the west in the afternoon, and again from the
south by the end of the day.

Knowledge of wind direction and speed is important to prevent possible
contamination of samples during digging.

The Phoenix mission is led by Smith at the University of Arizona with
project management at JPL and development partnership at Lockheed
Martin, Denver. International contributions come 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.


Media contacts: Guy Webster 818-354-5011
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov