[meteorite-list] Mars Rovers Heading Into Autumn of Robotic Life

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu May 6 13:16:41 2004
Message-ID: <200405061716.KAA08413_at_zagami.jpl.nasa.gov>

http://www.usatoday.com/tech/news/2004-05-06-rovers-fate_x.htm

Mars rovers heading into Autumn of robotic life
By Leonard David
space.com
May 6, 2004

Last month, NASA gave the go-ahead for both Mars Exploration Rovers - Spirit
and Opportunity - to keep on rolling.

Each robot has been handed up to five months of overtime assignments after
completing their individual three-month prime mission.

"Even though the extended mission is approved to September, and the rovers
could last even longer, they also might stop in their tracks next week or
next month," said Firouz Naderi, Manager of Mars Exploration at NASA's Jet
Propulsion Laboratory (JPL) in Pasadena, California, where the rovers were
built and are controlled.

Scientists and engineers running the automated emissaries from Earth have
already made a long, productive haul of exploration and discovery. And there
is no doubt that a very real and intense human/machine bonding has occurred.

That being the case, how does one cope with "robot death" on distant Mars?

Emotional ties

"There are very definitely strong emotional ties to the rovers," said Steve
Squyres of Cornell University in Ithaca, New York, and principal
investigator for the science payload carried on each of the rovers.

"We poured our hearts and souls into these things for years, so how wouldn't
there be? In fact, for me personally, it was actually a little hard just to
say goodbye to them at launch. It's going to be very hard to say goodbye to
them forever," Squyres told SPACE.com.

As to how Squyres and his colleagues will deal with the eventual loss of the
Mars machinery, he responded: "I don't know... ask me that when we get to
that point. The sadness from losing the vehicles will be balanced, in part,
by a big plus. We'll get our lives back! Flight operations have been
exhausting, involving a lot of time away from our families. So, in that
regard, life will certainly get easier after they're gone."

Squyres added that the impact of saying so long to the revered rovers is
lessened by a central fact.

"The mission has been so successful. If we lost them before they had
accomplished much...that would be very painful. Losing them after they have
led such long and productive lives will not be as bad. But still, it's going
to be hard," Squyres admitted.

Stayin' alive

The newly approved extension provides $15 million for operating the rovers
through September - added on top of the $820 million already spent.

Those two robot Mars pioneers are a technological brew of circuit boards,
computer, battery, solar panels, telecommunications hardware and science
instruments. Each the size of a golf-cart, Spirit and Opportunity must wheel
and deal with the planet's exotic environment, treacherous terrain, and
night/day temperature swings.

Despite being put together with tender loving care, the robots will
eventually succumb - be it by equipment breakdown or external forces. What
could go kaput first?

"That's a question we don't know the answer to," Squyres explained. "One
obvious possibility, of course, is that the gradual buildup of dust on the
solar arrays will slowly decrease the power output to the point that we
can't keep them alive any more. In that case, it'll be a very long, slow
decline in capabilities, and we'll see the end coming.

Another possibility, Squyres added, is that a rover would have a sudden,
abrupt failure of some critical component. "One day the thing simply
wouldn't work any more. I really can't guess which it'll be."

Near-death experience

There has already been a near-death experience within the family of Mars
rovers. For Spirit at Gusev Crater, it balked down early in its mission due
to computer conniptions. The robot's troubles quickly de-spirited JPL's
Jennifer Trosper, Spirit mission manager.

"I remember talking to my husband on the phone and I asked him first how his
day was. He said it was okay. And then he asked me how my day was going,"
Trosper said. "Well...I think I'm personally responsible for the loss of a
$400 million national asset," she recounted.

Spirit's woes, however, were eventually stabilized and the robot's software
was debugged. Today, Trosper is happy to report that the rover is "more than
a 100% of what it was on landing day."

Never run-of-the-mill

Busy at work on Mars, Spirit has been steadfastly clicking off wheel turns
as it heads for the base of "Columbia Hills", far off in the distance.

On the other side of red planet, Opportunity at Meridiani Planum is now
pulled up to the western rim of "Endurance Crater". The robot's camera gear
has begun relaying spectacular new views.

Meanwhile, back at JPL's Mars Exploration Rover (MER) mission control,
things have definitely gotten calmer and quieter. For one, rover teams have
switched from Mars-clock schedules to Earth-clock agendas designed to be
less stressful and more sustainable over a longer period.

"It's a strange feeling actually. For a long time we have been in a
different mode...so it's nice to be here," said Matt Wallace, JPL's
Opportunity Mission Manager. "It's starting to get a different feel...more
of a settling in for the long-haul type of feel," he told SPACE.com.

In many ways, tasking the rovers has become routine and, in some cases,
repetitive. But Wallace is quick to add: "It's never a run-of-the-mill job
when you're operating on Mars."

For the MER team, Wallace observed, having the rovers operate so well on
Mars is a by-product of people investing years of time. "There's a lot of
emotional energy...a lot of hard work."

Probes with personalities

JPL's Wallace managed the assembly and integration of Spirit and
Opportunity. "We watched these vehicles grow up...get launched...land and
operate," he said.

Although the NASA robots are mechanized twins at birth, each has a distinct
personality, Wallace observed.

Undergoing testing here on Earth prior to Mars sendoff, Wallace felt that
Spirit exhibited a tendency to be less well-behaved, the more adventurous of
the two vehicles. "Opportunity tended to kind of toe the line...a little
more staying inside the lines," he related.

Both robots have performed exceptionally well on Mars, from an engineering
and scientific perspective - with more to come, Wallace said. "I can't
really say that one or the other has become a favorite, or stolen the
show...at least not from our perspective."

Nevertheless, there will come a time when the Mars machines move no more.

Sounds of silence

Spirit's long-duration trek to Columbia Hills will be tough, but appears
doable, Wallace said.

Getting Spirit through the September time frame and into the fall at Gusev
Crater will be a challenge. The rover faces minimal power draw from the Sun
and will experience the coldest temperatures being farther from the equator
than Opportunity at Meridiani Planum.

Wallace said it's hard to predict how the rovers will eventually be
silenced.

First of all, there are scads of moving parts on each robot. Yet, even then,
a failed wheel or steering actuator, even with some breakdown of
communications equipment - a rover could still remain perky.

"There are some good, graceful degradation modes on the outside of the
rovers," Wallace said. Inside the robots, however, it's a different story.
There are a number of "single-string" components - such as power converters,
electronic boards - that could bring a rover to full-stop and mean
end-of-life.

"You never really hit the wall. There's always something that happens and
you try to recover for some period of time. You hold on, and hold on, to
hope," Wallace said.

When the day comes that Spirit and Opportunity pass away on Mars, Wallace
said, you have to step back and say: "Hey, this is a machine. That's why we
send machines to these hazardous environments before we send humans."

"But it's always tough at the end...no matter how it comes or when it
comes," Wallace concluded.
Received on Thu 06 May 2004 01:16:28 PM PDT