Mars Rover Spirit is Rolling Again After Memory Problems
Written by Ian O'Neill
Image taken by Spirit of a possible location for further scientific study (NASA)
It's been a worrying month for the health of Mars Expedition Rover Spirit. Two weeks ago, the embattled robot failed to wake up after three successive communication sessions, and then over the Easter weekend (April 12th and 13th), mission HQ noticed the rover had rebooted its systems at least twice during use of the high-gain antenna. The same thing happened on April 18th. In addition to this, Spirit has been suffering bouts of what seems to be an 'electronic amnesia', where the onboard computers have failed to record data onto their flash memory.
Today however, it would appear Spirit is still operational after over two weeks of remaining planted in the same position. It managed to enact commands sent from NASA to start driving once more, trundling 1.7 metres over the Martian regolith. She hasn't given up the good fight quite yet…
Since when have electronics on Earth ever lasted more than five years? I always seem to hit a two-year wall with my laptops when something nasty happens to the hardrive and/or motherboard (usually a day or two after the warranty runs out). But when we talk about the computers on board the Mars Expedition Rovers (MER), these electronics aren't in the snug safety of my office; they are on the surface of an alien planet, dealing with extremes in temperature, high energy particles and copious amounts of dust. What's more, the rovers were only designed to operate for a few months and yet they are still going strong, five years later. It's the NASA mission that just keeps on giving.
I think this is what makes the MER mission so impressive for me. Not only are Spirit and Opportunity still operational, they are operating 20 times longer than their designated lifetime and they are notching up a very healthy odometer count. Their cumulative distance travelled is not measured in metres, or kilometres; it's measured in tens of kilometres. They are giving us an unprecedented insight to the Martian surface, information that will shape our understanding of planetary science for generations to come.
But like any planetary mission, times can be tough, and both rovers have been tested to their engineered limits. Unfortunately, Spirit has been hit by a few more setbacks than Opportunity, but NASA has been able to find workarounds for each problem. The Mars Science Laboratory has a lot to live up to, I wonder if the MER mission will still be operational when the MSL finally touches down? Perhaps the next generation rover will have a robotic welcoming party!
The most recent issue for Spirit has been the flash memory problem. Flash memory helps the rovers store data even when they are powered down, but when the little rover forgets to actually store the data on the flash memory, something is obviously awry. In an attempt to make sure the rover can still take commands and to see if the computer problems persist, NASA ordered Spirit to travel 1.7 metres toward a target 150 metres away. All seems to be going well so far.
"We expect we will see more of the amnesia events, and we want to learn more about them when we do," said JPL's Sharon Laubach, chief of the rover sequencing team, which develops and checks each day's set of commands.
"We decided not to wait until finishing the investigations before trying to drive again. Given Spirit's limited power and the desire to make progress toward destinations to the south, there would be risks associated with not driving."
Hopefully keeping the rover mobile will help NASA troubleshoot the recent computer problems, but so far, she's still rolling over the Martian dirt…
Source: Physorg
Filed under: Mars
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April 25th, 2009 at 7:25 am
I think once people visit Mars, these rover should be brought back & placed in a museum. As the little rovers that COULD!
April 25th, 2009 at 8:04 am
"Bud Bray Says:
I think once people visit Mars, these rover should be brought back & placed in a museum. As the little rovers that COULD!"
i totaly agree !! they should be inspiration for all future generations ..
i'dd like to see viking missions in a museum too :p
April 25th, 2009 at 9:51 am
If I remember correctly, they only expected the rovers to last a few months due to the expected accumulation of dust on the solar panels. We know that moon dust is sticky due to static charge, we know that volcanic ash is sticky due to static charge, I believe they expected the same sticky dust situation on the rovers. But they we're surprised, and understandably thrilled, to discover that the rovers receive regular 'cleanings'. It could be wind blowing the dust off, but assuming the dust is electrostatically charged, then the cleanings might be electrostatic in nature as well. Maybe instead of the mechanical cleanings of wind, it's the electric field generated by the winds of a dust devil that do the actual cleaning. NASA says that rovers on Mars haven't experienced any consequences as a result of those e-fields. Maybe they haven't connected the dots yet, it happens sometimes. If the dust on the rovers is negatively charged, and the base of a dust devil is positively charged…ever use one of those static dusters?
http://www.nasa.gov/centers/goddard/news/topstory/2004/0420marsdust.html
"However, the team's observations indicate that smaller particles become negatively charged, while larger particles become positively charged. Dust devil winds carry the small, negatively charged particles high into the air, while the heavier, positively charged particles remain near the base of the dust devil. This separation of charges produces the large-scale electric field,
like the positive and negative terminals on a battery. Since the electrified particles are in motion, and a magnetic field is just the result of moving electric charges, the dust devil generates a magnetic field also."
I hope this post isn't too long or 'speculative' within the new guidelines.
April 26th, 2009 at 8:19 am
We should mount a mission to retreve them,to build better ones…nothing like actual road tested robots to improve..8^)
April 26th, 2009 at 8:37 am
I'd rather that they were put in a museum on Mars. It's their planet now.
April 28th, 2009 at 2:37 pm
solrey, I don't think that there is a relationship with the dust devils that creates magnitic fields and the memory loss of the rovers. Simply because the electronics are in an Faraday's cage. Two possible sources are here the cause, hitting by gamma rays and just plain old aging of the internal components on the chip that had to operate in really tough conditions.
It is very logicall that on a very dry planet where water is no where is found in the atmosphere that static charge will have an effect on the dust and they will start to float because they repell each other when they get charged by solar wind on the Moon.
Also regarding the dust devils, the charged particles might push away other charged particles on the solar panels, but the wind is mechanical caused by pressure. The mechanical pressure that caused the dust devil creates the magnetic fields because of the flying charged particles but the magnetic fields does not create the dust devil at all!
The magnetic fields might influence the dust devil's form, but it is not the source of teh dust devil, the atmospheric presure is the source.
solrey, you should take a basic course on electronics.