NASA's Spirit rover hit the 1,000-Martian day
of its mission on the red planet
Thursday, but the mission continues for the hardy robot.
To
celebrate the Martian milestone, rover mission managers released the McMurdo
panorama [image],
a mosaic of some 1,449 individual images taken by Spirit's panoramic camera.
"It has
been a surprise and delight to see the vehicle survive as long as it has," Jake
Mapijevic, engineering team chief for NASA's Mars Exploration Rover (MER) mission. "We
had anticipated a much shorter mission."
More than
10 times shorter, in fact.
When Spirit
landed
on Mars on Jan. 3, 2004, mission scientists and engineers hoped to wrangle at
least 90 Martian days - dubbed sols - out of the rover and its robotic twin Opportunity,
which touched
down on the red planet about 22 days later. At 24 hours and 37 minutes, one
sol is slightly longer than one Earth day.
But despite
an early software
glitch and ongoing
wheel issues, Spirit continues to return science from "Winter Haven" at its
Gusev Crater landing site. The region served as a sort of red planet retreat during
six months of harsh Martian
winter, Spirit's second
such season on Mars.
"We've
gotten through the worst of the winter season," Mapijevic told SPACE.com.
"Environmentally, we're going to go into another spring season, which is a
period where the atmosphere tends to change quite a bit on Mars."
The
mission continues
Altogether,
Spirit has spent more time exploring Mars than the last five International Space Station
astronaut crews spent in Earth orbit. Its robotic twin Opportunity - currently stationed
[image]
on the other side of Mars at Meridiani
Planum's Victoria Crater - will hits its own 1,000-sol mark in upcoming
weeks.
The two MER
rovers could likely survive until January, when mission scientists and
engineers hope to celebrate the third Earth anniversary of their red planet arrival.
During their
mission, Spirit and Opportunity returned evidence that liquid
water shaped the distant Martian past. Altogether, Spirit has roamed across
4.2 miles (6.8 kilometers) of Martian landscape at Gusev
crater, scaled
one of the Columbia
Hills and is preparing to head towards other interesting sites nearby.
Opportunity,
on the other hand, roved a stunning 5.8 miles (9.4 kilometers), and sits
perched on the rim of Victoria Crater, a massive depression that mission
scientists hope to descend into in the near future. The rover has its own wheel
issues and a motor winding glitch in the shoulder of its instrument-laden
robotic arm.
"Otherwise,
the rest of the vehicles' systems are pretty much fine," Mapijevic said.
Steven
Squyres, lead scientist for the rover mission at Ithaca, New York's Cornell
University, has attributed the long life of Spirit and Opportunity to their
robust design and talented handlers.
"These
vehicles are 10 times past their warranty," he said in a mission briefing last
month on Opportunity's travels. "It is really a remarkable team effort."
Spirit
still has a long way to go before it catches up with the reigning champions of
Martian missions: NASA's Viking
1 and Viking 2 landings in 1976.
Viking 2
lasted some 1,281 sols, a feat eclipsed by Viking 1's four-Earth year mission
that ended on Nov. 13, 1982. But unlike Spirit and Opportunity, which draw
their power from solar arrays that can decline over the years, the massive
Viking landers used radioisotope
thermal generators (RTGs) to generate electricity.
Break time
on Mars
Spirit and
Opportunity are taking a bit of a science break as Mars passes through solar
conjunction, a period in which Mars passes behind the Sun as seen from Earth.
"We haven't
actually heard from the vehicles for about five days now, and that's all traceable
to the noise environment with the Sun between Earth and Mars," Mapijevic said. "We
should be out of conjunction by next Monday."
During
conjunction, rover handlers don't expect to send many new commands to Spirit
and Opportunity, but the robots are expected to send home daily reports to
Earth and conduct science observations.
Mission
handlers at JPL, in the meantime, are taking advantage of the low activity
period for some much needed rest, Mapijevic said.
"I feel
quite privileged to have, in my work time, seen this milestone," he added. "This
period is kind of like the wildest imagination I could have had."
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