January 10, 2004
Spirit Extends
Wheels and Sends More Photos
NASA's Mars Exploration Rover Spirit has
successfully completed its stand-up activities by extending the
rear wheels. This puts the rover into a fully opened configuration
for the first time since pre-launch testing in Florida last spring.
Meanwhile, the rover is sending home sections
of a 360-degree color panorama it has taken and stored onboard,
plus other information about the terrain around its landing site,
Columbia Memorial Station in Mars' Gusev Crater.
Mission managers at NASA's Jet Propulsion
Laboratory, Pasadena, Calif., have decided that changing the
tilt of the lander platform will not be necessary before the
rover drives off, possibly allowing drive-off to occur late Tuesday
night or early Wednesday, Pacific Standard Time.
JPL's Chris Voorhees, who led the engineering
team that planned the unfolding sequences for Spirit and its
sister rover, Opportunity, said "Spirit has spent most of
the last seven months scrunched up inside of a tetrahedral-shaped
lander, and that is not the shape a rover wants to be. Over the
last several days, Spirit has performed a sort of reverse robotic
origami."
"The rover now stands at its full
height and all six wheels are in position for driving on the
surface of Mars," said Jennifer Trosper, mission manager
at JPL.
The rover is still attached to the lander.
The next step planned for Saturday evening (Pacific Standard
Time) is to command the rover to release connections between
the middle wheels and the lander. Under best-case conditions,
severing the final cable connection is planned for Sunday night,
followed by clockwise turns totaling 120 degrees on Monday night
into Tuesday, then drive-off toward the northwest on the following
martian day.
Pictures from Spirit's panoramic camera
continue to provide details about the martian ground and sky.
The rover transmitted home about 180 megabits of science data
in the past martian day, nearly 10 times the maximum daily capability
of Mars Pathfinder in 1997.
Horizon Haze Level Comparison
Photos
Click
for larger image
Courtesy NASA/JPL
JPL geologist Dr. Matt Golombek, co-chair
of the steering committee that evaluated potential landing sites
for Spirit and Opportunity, said the pictures are confirming
some predictions about the Gusev site. Rocks cover less of the
ground than at the three previous Mars landing sites -- about
three percent of ground area around Spirit compared with about
20 percent of the ground around each of Mars Pathfinder, Viking
1 and Viking 2.
Presenting the latest high-resolution color
mosaic from Spirit, Golombek said, "This is without question
the smoothest, flattest place we've ever landed on Mars, with
the possible exception of Viking 2."
Mosiac Image of Surface Southwest
of Lander
Click
for larger image
Courtesy NASA/JPL
Dr. Mark Lemmon a member of the rover science
team from Texas A & M University, College Station, said the
atmosphere at Spirit's site is dustier than at previous landing
sites, except during dust storms observed by the Viking landers.
The dust colors the sky and affects the appearance of objects
on the ground.
Higher above the ground, atmospheric densities
predicted for Spirit's descent closely matched the true conditions
measured from the spacecraft's deceleration, said JPL's Dr. Joy
Crisp. That is a good sign for Opportunity's descent two weeks
from now, though risks remain high for any landing on Mars.
Spirit arrived at Mars Jan. 3 (EST and
PST; Jan. 4 Universal Time) after a seven-month journey. Its
task is to spend the next three months exploring for clues in
rocks and soil about whether the past environment in Gusev Crater
was ever watery and suitable to sustain life.
Spirit's twin Mars Exploration Rover, Opportunity,
will reach its landing site on the opposite side of 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. As of Sunday morning, Opportunity will have
flown 428 million kilometers (266 million miles) since launch
and will still have 28 million kilometers (17 million miles)
to go before landing.
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