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This white oval shows the location of
Opportunity's landing site.
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PASADENA, California (CNN) --
Opportunity, the second of NASA's twin rovers, has made
the descent to the surface of Mars, touching down
successfully at 0505 GMT Sunday (12:05 a.m. ET).
NASA now has two rovers on the ground,
after Spirit landed on the red planet exactly three
weeks ago on January 3. Though Spirit's landing was near
perfect, the rover mission has had serious complications
in recent days.
"We're on Mars everybody,"
mission scientist Wayne Lee declared as fellow members
monitoring the landing at NASA's Jet Propulsion
Laboratory burst into wild applause .
Dampened by the problems with Spirit,
it had been a nervous few moments at mission control as
NASA officials counted down and checked off the various
descent maneuvers during what appeared to be a flawless
six-minute sequence.
As planned, the airbag-encased craft
bounced on the Martian surface and rolled gently for a
few minutes before coming to a complete stop upside
down.
NASA was awaiting further signals and
communications from Opportunity, including images of the
landing site.
There were "no fault tones"
detected in the radio signals back to Earth, suggesting
that the spacecraft arrived in good shape on Mars, a
mission control official said.
Moments after the landing, California
Gov. Arnold Schwarzenegger and former Vice President Al
Gore walked through mission control to congratulate the
workers there.
Opportunity is an exact replica of
Spirit but was programmed to land about 6,600 miles
(10,620 km) away on the opposite side of the planet, in
an area known as the Meridiani Planum -- a smooth plain
near Mars' equator, believed to be full of iron-bearing
hematite.
The semi-precious mineral usually
forms on Earth in the presence of liquid water --
leading scientists to think that water once flowed
there.
The area is believed to be quite
different from the reddish soil of Gusev Crater, where
Spirit landed earlier this month.
Opportunity's site makes the landing
more difficult than Spirit's, mission manager Jim
Erickson said.
It is also the highest altitude
landing by NASA on Mars.
In addition, Mars' increased distance
from Earth would lengthen the time needed to communicate
with the spacecraft.
Troubles with Spirit
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The Mars rover Spirit is shown in this NASA
drawing.
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Scientists are hoping the rover won't
have the same problems that have hit Spirit this week.
That rover was set to use its tools to
examine a nearby boulder when NASA lost contact with the
vehicle.
But NASA engineers found a work-around
Saturday for Spirit's problems, re-established
communication and regained the ability to control it.
"This is very good news,"
project manager Pete Theisinger told reporters.
Spirit's condition, Theisinger said,
"has been upgraded from critical to serious."
The rover is probably "three
weeks away from driving," he said, as engineers
study the problems and try to correct them with
additional work-arounds in the meantime.
NASA engineers are working to trace
the source of the problem as it could have implications
on Opportunity's mission.
Spirit uses Flash memory to
communicate with the flight software to establish a file
structure and will shut itself down if the process is
interrupted, Theisinger said.
Engineers guessed that Spirit's
troubles were in its Flash memory and set about sending
the rover a complex series of instructions to see if
they could get it to bypass the corrupted memory.
Theisinger said engineers sent Spirit
a command just before its daily "waking up,"
telling it to shut down and restart in what is known as
"cripple mode," using RAM instead of Flash for
its start-up instructions.
"That is precisely what
happened," Theisinger said, and Spirit then sent an
hour's worth of data back to Pasadena.
"Something in the flight software
talking to the Flash memory is causing us
difficulty," Theisinger said.
He said engineers did not know caused
the problem, but if it is purely a software problem, it
is likely fixable. If, however, a problem in the
hardware is affecting the software, repair may not be
possible.
But, "we have a vehicle that is
stable now," he said.
PASADENA, Calif. --
Mars has received a one-two exploration punch as the
second Rover -- Opportunity -- achieved a
successful landing tonight on the red planet.
Engineers and scientists
broke out in cheers and tears here at the Jet Propulsion
Laboratory (JPL), mission control for the Mars
Exploration Rover (MER) program.
Opportunity landed in the
Meridiani Planum region of Mars. The spacecraft's exact
whereabouts are not precisely known, but appears to have
touched down within a pre-determined ellipse within
Meridiani Planum.
Opportunity
Landing Is Near-Perfect
Opportunity looks to have
completed a near-perfect entry, descent, and landing.
Initial data suggested
that the spacecraft hit Mars' surface at a relatively
slow velocity -- some two to three times the force
of gravity. The airbag system is designed to sustain a
40 g's collision with Mars.
Indications are that
after coming to a stop, Opportunity was
"side-petal" down. That means it will have to
right itself on the red planet, then deflate its
airbags.
The spacecraft slammed
into the top of Mars' atmosphere at about 12,000 miles
per hour (5.4 kilometers per second). That event was
followed by a series of death-defying entry, descent and
landing events.
Taking all of six minutes
to plummet to the martian landscape, Opportunity bounced
across Mars wrapped in its cocoon of airbags before
coming to a complete stop.
"We're on Mars
everybody. We're getting a strong signal," said Rob
Manning, JPL's Entry, Descent and Landing manager.
Perfect
maneuvering
Opportunity landed on
Mars at 12:05 a.m. Sunday EST or 9:05 p.m. Saturday
PST.Early today, mission managers chose not to use an
option for making a final tweak to Opportunity's flight
path. Previously, as the spacecraft closed in on the
planet, the third and fifth out of five scheduled
maneuvers were skipped as unnecessary.
Getting to the exact
entry point using only three maneuvers since
Opportunity's launch was heralded early this morning by
JPL's Louis D'Amario, navigation team chief for the Mars
rovers.
Hematite-rich
territory
The rover's main task is
to explore the Meridiani Planum landing site and
determine whether that region could have had a past
environment that was watery and possibly suitable for
sustaining life.
Opportunity is on the
lookout for a gray hematite. Meridiani Planum has been
found by orbiting spacecraft sensors to be rich in gray
hematite. This type of iron oxide usually forms in
association with liquid water.
Here at JPL, as
Opportunity reached Mars, troubleshooting teams are
working around-the-clock to get the Spirit Mars
Exploration Rover back on line. It landed three weeks
ago, but subsequently ran into an apparent computer
glitch that halted its science gathering duties.
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