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And they're off! Well, one of them is anyway. As far as getting the new Mars
Exploration Rovers (MERs) up through the atmosphere and out past the thermosphere
is concerned, NASA has hit its half-way mark.
Grounded in Florida by a poor weather forecast Sunday and Monday, the MER-A
rover, now known as "Spirit," in its metal-shielded seat atop a Boeing
Delta II rocket, launched this afternoon at 1:58 pm EDT. Spirit will spend the
next seven months making its way to Mars. If all goes well it will hopefully
provide (to forgivably alter Neal Armstrong's famous first words of space exploration),
"one giant leap for planetary geology."
They say a little rain never hurt anyone, but it's easy to imagine why NASA
and JPL, after spending countless man-hours and about 800 million dollars combined
on the two rovers, wouldn't want to compromise Spirit's mission. Caution seems
to have been the name of the game this time around. The last two days' delays
were just the most recent in a line of multiple delays that held the rovers
back.
The Spirit was originally slated to launch on May 30. Mid-April, NASA announced
that the rover would not launch any sooner than June 6, due to a potentially
mission-fatal problem present in both MER spacecrafts. According to NASA, the
problem involved faulty circuit boards that might have caused the spacecrafts
to misinterpret signals as cables were severed during the landers' disconnection
from their cruise stages and then the rovers' disconnection from their landers.
The cables connect the main computer inside each rover to peripherals in its
lander, cruise stage and small deep space transponder.
Failure to fix this problem could have resulted in two less-than-responsive
MERs when it came time to land. On April 15, Peter Theisinger, MER project manager
at JPL, told the New York Times there was a "substantial risk"
that without a fix they would lose the mission. "We would not be able to
tell where the ground was and how fast we were coming down," Theisinger
said.
Spirit and MER-B (now known as "Opportunity") were both disassembled
and repaired at the Kennedy Space Center in Cape Canaveral, Fla. Two extra electronic
parts and about 20 wires were added to each circuit board to the fix the problem.
On May 27, NASA pushed the launch date back an extra couple days, no earlier
than June 8, to make time for engineering reviews.
Even as he gave Spirit and Opportunity a clean bill of health in a June 4 JPL
press release, Ed Weiler, associate administrator for space science at NASA
Headquarters in Washington expressed the attitude of cautious optimism behind
the extra measures. "Historically, two out of three missions, from all
countries who have tried to land on Mars, ended in failure," Weiler said.
"We have done everything we can to ensure our rovers have the best chance
of success, and today I gave the order to proceed to launch."
As has become typical of these robotic missions, there are still a few small
software quirks to iron out during flight. But what remains is simply to see,
once January 4, 2004 rolls around, whether the Spirit — after bouncing
around the surface of Mars in its airbag pyramid — emerges on the red soil
of Gusev Crater fully functional.
Matt Shindell
Geotimes contributing writer
Links:
Landing
the Mars Exploration Rovers, May 2003
Robotic
Field Geologists Take to Mars, May 2003
May
2003 Geotimes special issue on geology on Mars
Athena
science team site
JPL
Mars rover site
Download
footage of today's launch. You'll need RealPlayer
software.
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