Opportunity Joins Spirit on Mars
Sunday, January 25, 2004
PASADENA, Calif. — NASA's Opportunity rover successfully landed on
Mars late Saturday, arriving at the Red Planet exactly three weeks after
its identical twin set down, and prompting whoops and cheers of delight from
mission scientists.
"We're on Mars everybody," Rob Manning, manager of the entry, descent
and landing portion of the mission, shouted as fellow scientists at NASA's
Jet Propulsion Laboratory burst into wild applause.
The unmanned, six-wheeled rover landed at 9:05 p.m. PST in Meridiani Planum,
NASA said. The smooth, flat plain lies 6,600 miles and halfway around the
planet from where its twin, Spirit, set down on Jan. 3.
Minutes after the landing, former Vice President Al Gore and Gov. Arnold
Schwarzenegger strode through mission control, shaking hands with elated
scientists.
Together, the twin rovers make up a single $820 million mission to determine
if Mars ever was a wetter world capable of sustaining life. NASA launched
Spirit on June 10. Opportunity followed on July 7.
Earlier this week, Spirit developed serious problems, cutting off what
had been a steady flow of pictures and other scientific data. Scientists
said earlier Saturday, however, that they believe they can fix the problem
in the weeks ahead.
"We resurrected one rover and saw the birth of another today," said Ed
Weiler, NASA's associate administrator for space science.
At a jubilant news conference nearly two hours after the landing, NASA
administrator Sean O'Keefe broke open a bottle of champagne, as he did after
Spirit's landing, and toasted the mission's leaders.
"As the old saying goes, it's far better to be lucky than good, but you
know, the harder we work the luckier we seem to get," O'Keefe said, adding
"no one dared hope" that both rover landings would be so successful.
He said NASA officials hope to begin receiving photos from Opportunity
within a few hours, and added that Spirit was on its way to being fully repaired.
Opportunity, meanwhile, made what for it was a relatively soft landing,
scientists said.
Swaddled in protective air bags, it struck Mars at a force estimated to
be two to three times Earth's gravity. Engineers had designed it to withstand
as much as 40 G's, said Chris Jones, director of flight projects at JPL.
"It probably barely noticed it hit anything," Jones said.
Manning said the signals it was sending indicated it was in good shape.
The National Aeronautics and Space Administration had warned that it could
take as long as 22 hours after Opportunity's landing for it to make contact
with Earth, but it did so almost immediately.
Shortly before entering the martian atmosphere, Opportunity jettisoned
its cruise stage, shedding the disc-shaped structure that had provided power,
propulsion and communications capabilities during its seven-month trip through
space.
In the minutes before cruise separation, mission scientists at JPL broke
open containers of "good luck peanuts" they had brought for the occasion,
and Schwarzenegger and his wife, Maria Shriver, arrived to watch the drama
unfold.
As they prepared for the landing, scientists also said they were closing
in on the root of the problem that led the Spirit rover to begin spewing
gibberish and beeps instead of science and engineering data earlier this
week.
They brought stability to the six-wheeled vehicle by disabling its flash
memory, which is similar to the memory digital cameras use to store pictures,
said Orlando Figueroa, director of NASA's Mars exploration program.
"We made good progress overnight," project manager Pete Theisinger said
during an earlier news conference at JPL. "The rover has been upgraded from
critical to serious."
Spirit had resumed transmitting data Friday, but only in limited batches.
The malfunction, which appeared Wednesday, may prevent the rover from taking
another drive on Mars for as long as three weeks, Theisinger said.
Despite its woes, scientists said there is still a chance Spirit can take
up where it left off when it began malfunctioning. JPL Director Charles Elachi
said other NASA spacecraft, including Voyager, Magellan and Galileo, have
recovered from even graver problems.
"I am completely confident, without any hesitation, that I think we will
get that rover back to full operation," Elachi said.
The rover developed problems after working nearly flawlessly for days.
Mission members were able to stop the rover from rebooting its computer
as it had done roughly 130 times and place it in so-called "cripple" mode
to bypass its troubled flash memory.
They also succeeded in coaxing the robot to sleep after it stayed up two
nights in a row when it should have been turned off to conserve power.
The root cause of Spirit's problems remained elusive, however, and NASA's
inability to reproduce the problem in laboratory tests of its software on
Earth suggests that something is awry with the rover's hardware, Theisinger
said.
The problem may prevent Spirit from taking another drive on Mars for as
long as three weeks.
Before it began to malfunction, Spirit took thousands of pictures and
began its work prospecting the soil and rocks around its landing site.
As Spirit shut down systems and "slept" 124 million miles from Earth,
Opportunity made a flawless arrival on the other side of Mars.
Like Spirit did three weeks ago, it had to execute a choreographed sequence
of events to ensure its safe arrival. The only difference: Opportunity had
to open its parachute 4,500 feet higher above Mars than Spirit did to compensate
for the higher elevation of its landing site.
NASA sent Spirit to Gusev Crater, a broad depression believed to once
have contained a lake. It launched Opportunity toward Meridiani Planum, a
flat, smooth region relatively free of the reddish dust that cloaks Gusev.
Scientists believe Meridiani abounds in a mineral called gray hematite, which
typically forms in marine or volcanic environments rich in water.
Not since the 1976 landing of the twin Viking landers has NASA had two
working spacecraft on the surface of Mars.
NASA launched two rovers to double its chances of successfully landing
on Mars. Just one in three international efforts to land on the Red Planet
has succeeded.
The list of failures may include the British lander Beagle 2, which has
not been heard from since attempting to set down in December.
On the plus side, there are now a record five spacecraft either on or
near Mars. Two NASA spacecraft and one from the European Space Agency are
orbiting the planet.
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