NASA Associate Administrator for the Science Mission Directorate Edward Weiler praises NASA’s scientists and engineers gathered to pay tribute to the Mars rover Spirit Tuesday , July 19, 2011, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Spirit and its twin, Opportunity, landed on Mars in 2004 for what was supposed to be a three-month mission. Both survived longer than expected and uncovered geologic evidence that the red planet was once warmer and wet. Spirit operated on the surface for six years. In May, NASA declared Spirit dead after it had not responded to commands for more than a year. (AP Photo/Damian Dovarganes) |
LOS
ANGELES (AP) — NASA’s next Mars rover will land at the foot of a
towering mountain inside a 96-mile-wide crater to search for evidence
that the region once had conditions capable of supporting microbial
life, project officials announced Friday.
Gale
Crater was chosen as the target for the $2.5 billion Mars Science
Laboratory mission after an extensive review of dozens of potential
sites, officials said in webcast from the Smithsonian’s National Air and
Space Museum in Washington, D.C.
The
rover, nicknamed Curiosity, is expected to be launched this year and to
land on Mars in August 2012. It’s far bigger than the three rovers NASA
has previously sent to the red planet in search of geologic evidence
that the frigid, dusty planet was once warmer and wet, with conditions
that could potentially have supported a hardy form of life.
The
3-mile-high mountain in Gale Crater is layered and scientists believe
it is the surviving remnant of an extensive sequence of deposits. The
site also has a huge cut likened to the Grand Canyon that appears to
have been made by flowing water.
Mission
planners intend to send the instrument-laden Curiosity up the lower
flanks of the mountain to examine the layers. Its robotic arm is
designed to pick up samples that two of the 10 instruments will be able
to ingest for analysis.
Past
studies from orbiting spacecraft show the mineral signatures of clays
and sulfate salts, which form in the presence of water, concentrated in
older layers near the bottom of the mountain.
“Both
of those are key classes of minerals that tell us about the environment
on Mars and the interaction of water with that environment, and water
is critical to habitability,” said Dawn Sumner, a geologist from the
University of California, Davis.
Scientists
hope Curiosity will help determine what happened to the water on Mars,
how it went from wet to a frozen desert where dust devils spin across
the surface.
John
“Jack” Mustard, a planetary geologist at Brown University, said in a
statement that Gale Crater is believed to cross a “major time boundary”
documented in mineral history.
“We
believe that at Gale Crater, we have located that boundary where life
may have sprung up and where it may have been extinguished,” said
Mustard, who has science roles with an instrument aboard NASA’s Mars
Reconnaissance Orbiter and another instrument aboard Europe’s Mars
Express.
The
selection of a landing site came after years of debate and input from
the Mars science community. Sixty potential sites were discussed in
public meetings before a shortlist of four was created. In May, project
scientists cut the list to two, Gale and Eberswalde craters, and
forwarded the endorsement to NASA headquarters for the final decision.
The chosen crater is named for an Australian astronomer, Walter F. Gale.
The
choice of where to place a spacecraft on Mars involves maximizing the
chance of a safe landing as well as the likelihood of good science
results.
In
the mid-1970s, while the two Viking landers were en route to Mars,
engineers rushed to find alternate landing sites after the original
choices were discovered to be too dangerous. Both spacecraft landed
safely.
When
the twin Mars Exploration Rovers Spirit and Opportunity parachuted to
opposite sides of Mars in 2004, Opportunity fortuitously landed in an
area rich in the kind of geologic features the mission was looking for —
rocks showing evidence of a watery past. Spirit, however, had to drive
long distances to make discoveries.
Curiosity,
to be launched from Cape Canaveral Air Force Station, Fla., in November
or December, is 10 feet long, 9 feet wide, 7 feet tall and weighs about
2,000 pounds.
Unlike
its solar-powered predecessors — Spirit, Opportunity and the 1997
Pathfinder mission’s tiny rover Sojourner — Curiosity is
nuclear-powered, its energy originating from a radioisotope.
It
also will employ a new landing technology far different than the
airbags that were used to cushion the earlier rovers when they were
released from their parachutes and bounced to a stop.
Curiosity
also will parachute through the atmosphere, but then a rocket assembly
will fire to halt the descent and the rover will be lowered to the
surface on a tether.
The rover was supposed to be launched in 2009, but development snags pushed back the launch.
AP Science Writer Alicia Chang contributed to this report.
SOURCE: The Associated Press