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Thought you find this of interest.
Note the design difficulties...just like our robots. ;<)
TMT
http://www.usatoday.com/tech/science/space/2008-04-13-mars_N.htm?csp=1
Troubles parallel ambitions in NASA Mars project
By Traci Watson, USA TODAY
NASA's new Mars rover aims high. It's bigger, more powerful and more
sophisticated than any other robotic vehicle that has landed on
another planet. It will try to answer a big question: Has life existed
elsewhere in the solar system?
Its very ambition has gotten the rover in trouble. Thanks to a mix of
technological setbacks and engineering misjudgments, the rover's epic
scale is matched by epic problems. Its story offers a cautionary tale
as NASA plans to devote large chunks of its science budget in coming
years to grand "flagship" missions, including a spacecraft to return
Mars rocks to Earth and another that would visit a moon of Jupiter or
Saturn.
The new rover, known as the Mars Science Laboratory, is $235 million,
or 24%, over budget. Work on it has run so late that engineers are
racing to prepare the rover for its blastoff in 2009. After that, the
next good launch window, when Mars and the Earth are closest, is in
2011.
"They aimed high, and they got burned," says Arizona State
University's Phil Christensen, a Mars scientist who helped review
NASA's Mars program.
To make up for Mars Lab's ballooning cost, $1.2 billion, NASA has had
to raid the coffers of other science projects.
Last month, the Mars rover Spirit, which has roamed the Red Planet
since 2004, was threatened with being turned off to help pay for Mars
Lab. After word spread, NASA rescinded cuts to Spirit and twin rover
Opportunity.
'Pushing the envelope'
Spirit and Opportunity were a triumph for NASA, but next to Mars Lab,
they'll look crude. Their job was to look for water. Their successor
has a tougher task: to search for the molecules that are precursors to
life and for evidence of microbes at work.
That requires a big machine that relies on nuclear power rather than
the current rovers' solar panels. Mars Lab will carry a full chemistry
workshop and a robotic drill arm for gathering rock samples.
Mars Lab, conceived in 2000 and given formal approval in 2006, "is the
most challenging planetary mission that's ever been flown," says Doug
McCuistion, head of NASA's Mars program. "We're pushing the envelope
in a number of areas, and it just kind of built up."
Among the problems:
* The heat shield. Such a big rover needs heavy protection to get it
through the Martian atmosphere. It took engineers until mid-2007 to
determine that the material they'd chosen wouldn't work.
* The 90-plus motors that drive the rover's moving parts, such as its
wheels. Engineers spent years working on cutting-edge motors. They
decided last year that it would take too much time and money to
develop them.
* The scientific instruments. Ranging from cameras to chemical
sensors, the instruments ran so over budget that last year NASA
officials kicked one instrument off the rover and stopped work on
another. Work on the two instruments was restarted after corporate,
foreign and federal sponsors outside NASA came up with more money.
* The landing system. Because it's so big, Mars Lab will touch down on
the planet using a new combination of braking rockets, parachutes and
a long tether that will lower it to the ground. Engineers encountered
glitches developing the system.
Needed: 'Several miracles'
No single item can be blamed for the bulk of the cost growth,
McCuistion says. It all added up.
"You ended up with several miracles (needed) to get the mission
achieved, instead of just one," says Brown University planetary
scientist John Mustard, chair of a group that provides Mars advice to
NASA.
In retrospect, "we underestimated what it was going to take," concedes
the lab's project manager, Richard Cook of NASA's Jet Propulsion
Laboratory. "To do it right, we're going to need more funding."
What's more, every change has a ripple effect, Cook says. So the
decision in 2007 to use different and heavier motors on the rover's
moving parts meant that other weight-bearing parts of the rover had to
be redesigned, upping the cost more.
Cook and others concede that they may have been able to head off some
of the headaches by spending more money earlier than they thought was
needed. That would have allowed them to experiment with new
technologies without having so much of a ripple effect on the rest of
the spacecraft.
Despite the missteps, Edward Weiler, the acting head of NASA's science
division, says he'll do what it takes to fund the rover. Many NASA
science projects will have take a small hit to pay for the overruns.
"I'm trying to spread the pain," Weiler says. "Everything is fair
game."
Outside scientists agree with NASA officials that the rover is a
difficult endeavor. They say it will be worth it, and anything less
ambitious couldn't tackle the big questions Mars Lab will.
"Was it perhaps a quantum leap forward as opposed to an incremental
step?" Mustard says. "Yes, that might be the case. But that's what
NASA prides itself on."
MARS SCIENCE LABORATORY: BY THE NUMBERS
The Mars Science Laboratory, the next robotic vehicle to explore the
surface of the Red Planet, will be far more sophisticated than the two
Mars Exploration Rovers already roaming the planet.
Mars Science Laboratory Mars Exploration Rover
Total weight 1,984 pounds 384 pounds
Length 9 feet 5.2 feet
Power production Nuclear: 2.5 kilowatt hours per day Solar: 0.6
kilowatt hours per day
Weight of scientific instruments 176 pounds 15 pounds
Number of potential landing sites on Mars Hundreds Ten
Intended lifetime driving distance 12 miles 0.6 miles
Source: NASA
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