Thinking on Mars: The Brains of NASA's Red Planet Rovers

Article from Yahoo News:

Humans have long depended on machines to explore strange, new worlds;
guiding mechanical rovers from millions of miles away, then waiting --
and hoping -- that the robotic beast carried out its instructions.

Spirit and Opportunity, NASA (news - web sites)'s twin Mars Exploration
Rovers (MER), are no exception to the rule. But while their onboard
computers are based on past spacecraft computing systems, engineers have
beefed up their memory capacities to handle what is hoped to be a slew of
data from Mars despite a serious glitch with the rover, Spirit.

"These computers are absolutely identical, and what's more impressive is
that there is just one for each rover," said Victor Scuderi, manager of
space products for Information and Electronics Warfare Systems (IEWS) in
Manassas, Virginia. IEWS, part of BAE Systems, provided the computer at
the heart of the MER rovers. "It's quite unusual to have a single
computer for the whole mission," Scuderi said, adding that many missions
tend to have redundant systems as a guard against failure.

But the MER computers are based on systems that have been proven
repeatedly in the past and present, particularly in the 1997 Mars
Pathfinder mission and the ongoing Mars Odyssey, which has led to some
faith in the technology on NASA's part.

A standard Martian brain

Both the hardware and operating software onboard Spirit and Opportunity
are very similar to those used in the highly successful Pathfinder
mission, which dropped a lander and the small Sojourner rover onto red
planet.

At the nerve center of each MER rover is a 6-by 9-inch electronics board
containing one computer responsible for every process that goes into a
mission, whether it be monitoring spacecraft health in transit, deploying
parachutes during landing or roving about the red planet. The computer,
called a RAD6000, is a tried and true component for NASA space mission
that has formed the brains of past Mars missions in the, as well as the
recent Stardust comet encounter.

"This has become a real workhorse for space missions," Scuderi said. "We
currently have about 150 of these [computers] in space today."

RAD6000 microprocessors are radiation-hardened versions of the PowerPC
chips that powered Macintosh (news - web sites) computers in the early
1990s, with 128 megabytes of random access memory (RAM) and capable of
carrying out about 20 million instructions per second. A critical feature
of the spaceworthy chips -- developed jointly by BAE systems, JPL and the
Air Force Research Laboratory -- is the radiation shielding, which uses a
series of resistors and capacitors to ground harmful radiation before it
can damage onboard electronics.

"In space, there are tons of high-energy particles, X-rays, gamma rays,
you name it," Scuderi told SPACE.com. "If [a computer] is not protected
against them, they could create short circuits, create fake bits or burn
up electronics."

Since the MER rovers are much larger than Sojourner, with missions
planned to last almost three times as long, JPL engineers added another
256 megabytes of "flash" memory - the same type used to store pictures in
digital cameras - to hold more mission data. Altogether, each MER robot
has more than 1,000 times the memory capacity as Sojourner.

The operating systems running on Spirit and Opportunity are based on a
flexible commercial platform initially chosen by JPL engineers for its
reliability.

"[JPL] needed the tools to be able to develop their mission software on a
system from someone with a proven track record," explained Steven
Blackman, director of business development for aerospace and defense for
the software company Wind River. The Alameda, California-based company
developed the VxWorks real-time operating system used in aboard the MER
rovers, as well as other NASA and European Space Agency missions.

In addition to VxWorks' reliability, the system allows users to add
software patches -- such as a glitch fix or upgrade -- without
interruption while a mission is in flight. "We've always had that
[feature] so you don't have to shut down, reload and restart after every
patch," Blackman said, adding that some commercial desktop systems
require users to reboot their computers after a patch.

Keeping warm and in touch

Rover computers, as well as equipment aboard Spirit and Opportunity, can
only operate properly within a set temperature range, which stretches
from -40 degrees Fahrenheit at the low end on up to 104 degrees
Fahrenheit at the high.



While a hot day on Mars is nothing for the robot brains to worry over --
they tend to top out at 71 degrees Fahrenheit -- nighttime is another
matter. Once the Sun sets on Mars, the temperature can drop down to a -
140 degrees Fahrenheit. To survive the frigid Martian night, MER
computers are housed in warm electronics boxed heated by a combination of
electric heaters, eight radioisotope heater units as well as the natural
warmth from the electronics themselves.

Each rover computer is programmed to periodically takes its own
temperature and check its ability to communicate with Earth to verify
that all systems are in working order and that the rover is "healthy."
The MER computer also responsible its rover's navigation, and constantly
uses images from an array of hazard and navigation cameras, as well as
standing movement orders from mission controllers, to keep itself moving
smoothly in the right direction.

A quirky Spirit

The current Mars rovers may rely on proven computer technology, but for
Spirit the journey has not been glitch-free.

After a promising start to its mission, the Spirit rover -- the first of
the MER twins to land on Mars -- stopped sending proper data to JPL
scientists 18 days into the mission and later baffled ground controllers
by rebooting itself over and over again. Since then, mission controllers
were able to regain reliable communications with the rover and continue
to study what may have caused the malfunction.

Recent reports cite the breakdown of software that controls file
management in Spirit's computer memory as the leading theory to the
rover's computer woes. While JPL scientists have expressed confidence
they can overcome the problem, possibly in a matter of weeks, the
hardware and software manufactures behind the computer system are more
than ready to help.

"If they ask, we come," Blackman said, echoing the enthusiasm of BAE
officials. "I think when something like this happens, the whole community
responds to it."
--
Regards, Terry King ...In The Woods In Vermont

The one who Dies With The Most Parts LOSES!! What do you need?

Interesting lack of spirit updates on the JPL website.

Last press release (about the problem) was a few days ago.

I wonder when we're going to hear how they're doing?

jt

The current Mars rovers may rely on proven computer technology, but for
Spirit the journey has not been glitch-free.

After a promising start to its mission, the Spirit rover -- the first of
the MER twins to land on Mars -- stopped sending proper data to JPL
scientists 18 days into the mission and later baffled ground controllers
by rebooting itself over and over again. Since then, mission controllers
were able to regain reliable communications with the rover and continue
to study what may have caused the malfunction.

Recent reports cite the breakdown of software that controls file
management in Spirit's computer memory as the leading theory to the
rover's computer woes. While JPL scientists have expressed confidence
they can overcome the problem, possibly in a matter of weeks, the
hardware and software manufactures behind the computer system are more
than ready to help.

"If they ask, we come," Blackman said, echoing the enthusiasm of BAE
officials. "I think when something like this happens, the whole community
responds to it."
--
Regards, Terry King ...In The Woods In Vermont

The one who Dies With The Most Parts LOSES!! What do you need?

Interesting lack of spirit updates on the JPL website.

Last press release (about the problem) was a few days ago.

I wonder when we're going to hear how they're doing?

jt

The current Mars rovers may rely on proven computer technology, but for
Spirit the journey has not been glitch-free.

After a promising start to its mission, the Spirit rover -- the first of
the MER twins to land on Mars -- stopped sending proper data to JPL
scientists 18 days into the mission and later baffled ground controllers
by rebooting itself over and over again. Since then, mission controllers
were able to regain reliable communications with the rover and continue
to study what may have caused the malfunction.

Recent reports cite the breakdown of software that controls file
management in Spirit's computer memory as the leading theory to the
rover's computer woes. While JPL scientists have expressed confidence
they can overcome the problem, possibly in a matter of weeks, the
hardware and software manufactures behind the computer system are more
than ready to help.

"If they ask, we come," Blackman said, echoing the enthusiasm of BAE
officials. "I think when something like this happens, the whole community
responds to it."
--
Regards, Terry King ...In The Woods In Vermont

The one who Dies With The Most Parts LOSES!! What do you need?

Interesting lack of spirit updates on the JPL website.

Last press release (about the problem) was a few days ago.

I wonder when we're going to hear how they're doing?

jt

The current Mars rovers may rely on proven computer technology, but for
Spirit the journey has not been glitch-free.

After a promising start to its mission, the Spirit rover -- the first of
the MER twins to land on Mars -- stopped sending proper data to JPL
scientists 18 days into the mission and later baffled ground controllers
by rebooting itself over and over again. Since then, mission controllers
were able to regain reliable communications with the rover and continue
to study what may have caused the malfunction.

Recent reports cite the breakdown of software that controls file
management in Spirit's computer memory as the leading theory to the
rover's computer woes. While JPL scientists have expressed confidence
they can overcome the problem, possibly in a matter of weeks, the
hardware and software manufactures behind the computer system are more
than ready to help.

"If they ask, we come," Blackman said, echoing the enthusiasm of BAE
officials. "I think when something like this happens, the whole community
responds to it."
--
Regards, Terry King ...In The Woods In Vermont

The one who Dies With The Most Parts LOSES!! What do you need?

yep.."RAD6000 microprocessors are radiation-hardened versions of the PowerPC
chips that powered Macintosh (news - web sites) computers in the early
1990s, with 128 megabytes of random access memory (RAM) and capable of
carrying out about 20 million instructions per second."

good old Mac

yep.."RAD6000 microprocessors are radiation-hardened versions of the PowerPC
chips that powered Macintosh (news - web sites) computers in the early
1990s, with 128 megabytes of random access memory (RAM) and capable of
carrying out about 20 million instructions per second."

good old Mac

yep.."RAD6000 microprocessors are radiation-hardened versions of the PowerPC
chips that powered Macintosh (news - web sites) computers in the early
1990s, with 128 megabytes of random access memory (RAM) and capable of
carrying out about 20 million instructions per second."

good old Mac

On Wed, 28 Jan 2004 11:39:19 -0500, Terry King
wrote:
But the MER computers are based on systems that have been proven
repeatedly in the past and present, particularly in the 1997 Mars
Pathfinder mission and the ongoing Mars Odyssey, which has led to some
faith in the technology on NASA's part.

Pathfinder software was badly screwed up, the thing would lock up
every few minutes due to a threading issue called priority inversion,
which for the nontechnical means: (a) in juggling the several tasks
that a computer does at once, it kept dropping the balls, (b) it was
programmed by novices, (c) it was not tested, or failed tests and was
launched anyway.

If the new rovers are similar to the old one, you do the math.

J.

On Wed, 28 Jan 2004 11:39:19 -0500, Terry King
wrote:
But the MER computers are based on systems that have been proven
repeatedly in the past and present, particularly in the 1997 Mars
Pathfinder mission and the ongoing Mars Odyssey, which has led to some
faith in the technology on NASA's part.

Pathfinder software was badly screwed up, the thing would lock up
every few minutes due to a threading issue called priority inversion,
which for the nontechnical means: (a) in juggling the several tasks
that a computer does at once, it kept dropping the balls, (b) it was
programmed by novices, (c) it was not tested, or failed tests and was
launched anyway.

If the new rovers are similar to the old one, you do the math.

J.

On Wed, 28 Jan 2004 11:39:19 -0500, Terry King
wrote:
But the MER computers are based on systems that have been proven
repeatedly in the past and present, particularly in the 1997 Mars
Pathfinder mission and the ongoing Mars Odyssey, which has led to some
faith in the technology on NASA's part.

Pathfinder software was badly screwed up, the thing would lock up
every few minutes due to a threading issue called priority inversion,
which for the nontechnical means: (a) in juggling the several tasks
that a computer does at once, it kept dropping the balls, (b) it was
programmed by novices, (c) it was not tested, or failed tests and was
launched anyway.

If the new rovers are similar to the old one, you do the math.

J.