From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Dec 05 2003 - 08:32:40 PST
----- Original Message -----
From: NASA Jet Propulsion Laboratory
Sent: Tuesday, December 02, 2003 2:04 PM
To: ljk4_at_msn.com
Subject: Mars Rovers Head for Exciting Landings in January
MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov http://www.jpl.nasa.gov/
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Donald Savage 202-358-1547
NASA Headquarters, Washington D.C.
NEWS RELEASE: 2003-158 December 2, 2003
Mars Rovers Head for Exciting Landings in January
NASA's robotic Mars geologist, Spirit, embodying America's enthusiasm
for exploration, must run a grueling gantlet of challenges before it
can start examining the red planet. Spirit's twin Mars Exploration
Rover, Opportunity, also faces tough martian challenges.
"The risk is real, but so is the potential reward of using these
advanced rovers to improve our understanding of how planets work,"
said Dr. Ed Weiler, associate administrator
for space science at NASA Headquarters, Washington, D.C.
Spirit is the first of two golf-cart-sized rovers headed for Mars
landings in January. The rovers will seek evidence about whether the
environment in two regions might once have been capable of supporting
life. Engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif.,
have navigated Spirit to arrive during the evening of Jan. 3, 2004, in
the
Eastern time zone.
Spirit will land near the center of Gusev Crater, which may have once
held a lake. Three weeks later, Opportunity will reach the Meridiani
Planum, a region containing exposed
deposits of a mineral that usually forms under watery conditions.
"We've cleared two of the big hurdles, building both spacecraft and
launching them," said JPL's Peter Theisinger, project manager for the
Mars Exploration Rover Project. "Now
we're coming up on a third, getting them safely onto the ground."
Since their launches on June 10 and July 7 respectively, each rover
has been flying tucked inside a folded-up lander. The lander is
wrapped in deflated airbags, cocooned within a protective aeroshell
and attached to a cruise stage that provides solar panels, antennas
and steering for the approximately seven month journey.
Spirit will cast off its cruise stage 15 minutes before hitting the
top of the martian atmosphere at 5,400 meters per second (12,000 miles
per hour). Atmospheric friction during the next four minutes will heat
part of the aeroshell to about 1,400 C (2,600 F) and slow the descent
to about 430 meters per second (960 mph). Less than two minutes before
landing, the spacecraft will open its parachute.
Twenty seconds later, it will jettison the bottom half of its
aeroshell, exposing the lander. The top half of the shell, still
riding the parachute, will lower the lander on a tether. In the final
six seconds, airbags will inflate, retro rockets on the upper shell
will fire, and the tether will be cut about 15 meters (49 feet) above
the ground.
Several bounces and rolls could take the airbag-cushioned lander about
a kilometer (0.6 mile) from where it initially lands. If any of the
initial few bounces hits a big rock that's too sharp, or if the
spacecraft doesn't complete each task at just the right point during
the descent, the mission could be over. More than half of all the
missions launched to
Mars have failed.
JPL Director Dr. Charles Elachi said, "We have done everything we know
that could be humanly done to ensure success. We have conducted more
testing and external reviews
for the Mars Exploration Rovers than for any previous interplanetary
mission."
Landing safely is the first step for three months of Mars exploration
by each rover. Before rolling off its lander, each rover will spend a
week or more unfolding itself, rising
to full height, and scanning surroundings. Spirit and Opportunity each
weigh about 17 times as much as the Sojourner rover of the 1997 Mars
Pathfinder mission. They are
big enough to roll right over obstacles nearly as tall as Sojourner.
"Think of Spirit and Opportunity as robotic field geologists," said
Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal
investigator for the rovers' identical sets of science instruments.
"They look around with a stereo, color camera and with an infrared
instrument that can classify rock types from a distance. They go to
the rocks that seem most interesting. When they get to one, they reach
out with a robotic arm that has a handful of tools, a microscope, two
instruments for identifying what the rock is made of, and a grinder
for getting to a fresh, unweathered surface inside the rock."
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. For information about the Mars Exploration Rover
project on the Internet,
visit http://mars.jpl.nasa.gov/mer .
For Cornell University's Web site about the science payload,
visit http://athena.cornell.edu http://athena.cornell.edu/ .
-end-
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