Slashdot Mirror
Mars Rover "Spirit" In Danger
Riding with Robots writes "Just days after announcing that the Mars Phoenix Lander has met its icy demise, NASA reports that a dust storm has left the rover Spirit on the edge of power failure. During one recent Martian day, the robotic geologist's solar array produced only 89 watt hours of energy, the lowest output by either rover in their nearly five years on Mars. Mission managers are taking steps to protect the hardy, battle-worn spacecraft, but the agency describes Spirit's status as 'vulnerable.'"
Isn't this just an effect of reduced sunlight during winter? Or is Spirit near the equator / other hemisphere? I know the Phoenix shutdown is at least partly due to seasonal changes
From the Press Release:
"NASA's Phoenix Mars Lander has ceased communications
after operating for more than five months. As anticipated, seasonal
decline in sunshine at the robot's arctic landing site is not
providing enough sunlight for the solar arrays to collect the power
necessary to charge batteries that operate the lander's instruments."
The English word fart is one of the oldest words in the English vocabulary.
Viking 1 - orbiter + lander - dead and dead (fuel leak, battery)
Viking 2 - orbiter + lander - dead and dead (out of gas, bad software update)
Pathfinder - lander - lost contact in 12 weeks.
Sojourner - rover - lost contact in 12 weeks.
Spirit - rover - critically low power, busted wheel
Opportunity - rover - still roving strong
Phoenix - rover - dead, but we're still listening
Think next time they'll add a cleaning brush attachment for the arm?
These things had a 90 day life span! Next time I think we should send them in pairs so they can help each other out in a pinch.
actually... if you look at performance and power consumption... it would make sense to run advanced tasks on graphics cards (GPGPUs) then on processors...
It's fall in the northern hemisphere of Mars where Phoenix is located, so it dying was entirely expected, and although it lasted longer than its mission, they were hoping to get a few more weeks out of it. Landing was just a month before the summer solstice, so it had 30 days of conditions that started good and improved, then 130 days of declining conditions. Since it's in the arctic circle, it had complete daylight until a month or two ago, when the sun started setting again.
Spirit and Opportunity, however, are in the southern hemisphere, and it's early spring. Between the dust on Spirit's solar panels and being about 12 degrees further from the equator than Opportunity, things got a little worrisome for Spirit over the winter, but her minimum power levels at that time were over twice the 89 Watt-hours quoted in the article.
Low power is slightly less of a concern now than it was then, because the surface temperature should be higher and so electronics should need less heating, but that huge drop in power is probably more than enough to make up the difference. The other potential positive factor is Spirit's batteries had a decent level of charge when the storm started, so if the storm dissipates quickly they'll probably be in the clear. Trying to maintain 89 W-hr for several months, however, could very easily be fatal, so they're trying to use an absolute minimum of power to keep her out of fault mode.
Spirit actually hadn't moved an inch for several months to save power until a week or two ago. Her team had parked her on a sloped rock face at about a 30 degree angle to square her solar panels to the noon sun over the winter, and because of relatively clear skies, she was even able to take a high resolution panorama (link is to an index, not directly to the giant 42 MB image) and do some stationary science. As the sun angle increased, they had just started inching back towards a 20 degree tilt to follow it when the dust storm hit. There's a rather dramatic picture of what that 30 degree tilt looks like on the program site.
As of the last report I've seen, the atmosphere is 69% opaque due to suspended dust (although I believe more than 31% of the sunlight diffuses through indirectly), and the dust coating on Spirit's solar panels is only letting through 32% of of the sunlight that actually reaches them. In the past they'd had good luck with winds cleaning the panels off, but that hasn't happened in a while. The team is hoping that the same seasonal weather that brings on these dust storms will generate a few lucky dust devils.
Opportunity, on the other side of the planet meanwhile, has been getting 500-600 Watt-hours and averaging about 50 meters per day of progress towards the huge crater Endeavor, which is 12 km away.
And what nutjob modded the parent as a troll? Sheesh! And to think we probably let that person vote, too.
Here's the things one or both rovers have survived so far:
* Full flash memory
* Non-rotating wheel
* Dusty solar panels
* Stuck in dust dunes
* Two winters (very cold)
* Going down and up steep crater slopes
* A global dust-storm that put power at the edge (about a year ago)
* Broken joint motor
* Power leak
That's nine. If they follow feline conventions, then number 10 will be it.
Table-ized A.I.
Not trolling, but NASA is an expert at setting expectations low, then milking things for all they're worth when they keep working 'beyond expectations'.
So, good job, but enough of the 'will only last for 2 months' bullshit already.
Well, I had read about the fear of issues with dust settling on the solar cells; I figured they should have used the same mechanism that NASCAR uses to clear the lenses of the car-cams. A clear, celluloid cover over the cells, which can be rolled-up off of a spool on either side of the cells, and a brush along the top of the spool. Every time dust collects on the cells, the spool winds out a new clear celluloid cover, the dusty bit is brushed off, and rolled up. Next time, the motor rolls the opposite direction.
Oh well, maybe the next rover will have something like this.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.