Hello Thomas and group,
Adirondack and many other rocks in the rover photos
appear to be altered by wind erosion. This can leave very sharp faces and are
known as ventifacts. Other terms used for this effect are
dreikanter also windkanter. Seasonal changes in wind direction
can cause two or three distinct planes on the rock surface. They are
common in windy desert environments.
Dan Wray
COMETS
----- Original Message -----
Sent: Tuesday, January 20, 2004 7:35
AM
Subject: Re: [meteorite-list] Spirit
Drives to a Rock Called 'Adirondack' for Close Inspection
Ron and List,
Does it appear to you that there may have been some shearing on the right
hand side of the rock called 'Adirondack'?
Guy
Webster (818) 354-5011 Jet Propulsion Laboratory, Pasadena,
Calif.
Donald Savage (202) 358-1547 NASA Headquarters, Washington,
D.C.
News Release: 2004-024 January 19, 2004
Spirit Drives to
a Rock Called 'Adirondack' for Close Inspection
NASA's Spirit rover
has successfully driven to its first target on Mars, a football-sized
rock that scientists have dubbed Adirondack.
The Mars Exploration
Rover flight team at NASA's Jet Propulsion Laboratory, Pasadena, Calif.,
plans to send commands to Spirit early Tuesday to examine Adirondack with
a microscope and two instruments that reveal the composition of rocks,
said JPL's Dr. Mark Adler, Spirit mission manager. The instruments are
the Mössbauer spectrometer and the alpha particle X-ray
spectrometer.
Spirit successfully rolled off the lander and onto the
martian surface last Thursday. To make the drive to Adirondack, the
rover turned 40 degrees in short arcs totaling 95 centimeters (3.1
feet). It then turned in place to face the target rock and drove four
short moves straightforward totaling 1.9 meters (6.2 feet). The
moves covered a span of 30 minutes on Sunday, though most of that
was sitting still and taking pictures between moves. The total
amount of time when Spirit was actually moving was about two
minutes.
"These are the sorts of baby steps we're taking," said JPL's
Dr. Eddie Tunstel, rover mobility engineer.
"The drive was
designed for two purposes, one of which was to get to the rock," Tunstel
said. "From the mobility engineers' standpoint, this drive was geared to
testing out how we do drives on this new surface." Gathering new
information such as how much the wheels slip in the martian soil will
give the team confidence for more ambitious drives in future weeks and
months.
"Adirondack is now about one foot (30 centimeters) in front
of the front wheels," he said.
Scientists chose Adirondack to be
Spirit's first target rock rather than another rock, called Sashimi, that
would have been a shorter, straight-ahead drive. Rocks are time capsules
containing evidence of the environmental conditions of the past, said Dr.
Dave Des Marais, a rover science-team member from NASA Ames Research
Center, Moffett Field, Calif. "We needed to decide which of these time
capsules to open."
Sashimi appears dustier than Adirondack. The
dust layer could obscure good observations of the rock's surface, which
may give information about chemical changes and other weathering
from environmental conditions affecting the rock since its surface
was fresh. Also, Sashimi is more pitted than Adirondack. That makes it
a poorer candidate for the rover's rock abrasion tool, which
scrapes away a rock's surface for a view of the interior evidence
about environmental conditions when the rock first formed. Adirondack
has a "nice, flat surface" well suited to trying out the rover's
tools on their first martian rock, Des Marais said.
"The
hypothesis is that this is a volcanic rock, but we'll test
that hypothesis," he said.
Spirit arrived at Mars Jan. 3 (EST and
PST; Jan. 4 Universal Time) after a seven-month journey. In coming weeks
and months, according to plans, it will be exploring for clues in rocks
and soil to decipher whether the past environment in Gusev Crater was
ever watery and possibly suitable to sustain life.
Spirit's twin Mars
Exploration Rover, Opportunity, will reach Mars on Jan. 25 (EST and
Universal Time; 9:05 p.m., Jan. 24, PST) to begin a similar examination
of a site on the opposite side of the planet from Gusev
Crater.
JPL, a division of the California Institute of Technology
in Pasadena, manages the Mars Exploration Rover project for
NASA's Office of Space Science, Washington, D.C. Images and
additional information about the project are available from JPL
at
http://marsrovers.jpl.nasa.gov
from Cornell University,
Ithaca, N.Y., at
http://athena.cornell.edu/
. -end-
______________________________________________ Meteorite-list
mailing
list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
Do you Yahoo!? Yahoo! Hotjobs: Enter
the "Signing Bonus" Sweepstakes
|