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.'"
This has required mission managers to shut down the dual graphics cards and switch to the integrated graphics. Really sad.
Can you really call a rover a "spacecraft"? That is kind of like dipping my car in the ocean and call it a boat.
It would be very sad to see Spirit run out of power, but honestly, both the rovers have performed so far beyond their original expectations, it's astounding. I seem to recall they were originally meant for something like a two-month mission...four years ago.
So if we do lose Spirit soon, for my part, I think we can be satisfied with what it's already accomplished.
Dan Aris
Fun. Free. Online. RPG. BattleMaster.
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
Indeed, Spirit can legitimately unfurl a "Mission Accomplished" banner, now.
And have no regrets about it.
1. An 89 watt-hour high-speed dash to blow the dust off. By my calculations they should be able to go 6 feet at 4 mph so ok forget that.
2. Launch a nuclear powered feather dusting support rover. No that's stupid.
3. Fire a kazillajoule laser at Mars to energize the solar panels. This is actually the least worst idea so far which is depressing.
4. Spend the remaining energy teaching the rover to do the Hammer Dance with it's eight independently swiveling wheels. If you got to go down, go down doing the Hammer Dance that's what I always say which is maybe why nobody sits with me in the cafeteria.
Equine Mammals Are Considerably Smaller
NASA probably thought of that, but the issue is how practical any wiper system would be. Unlike automobile wipers, there's no air or water supply to remove the dust. Adding a system to compress air would have added unacceptable weight to the rover and every little bit counts (even if would work reliably under Mars conditions). A water system would have been out of the question. A waterless/airless system then depends on the material you would use. Such a material would have be softer than the panels or they would damage them; however, a softer material (rubber, polypropylene, polyethylene) probably would not survive the extreme conditions of Mars.
And that's just the survivability aspects. Now factoring the usability aspects: Some sort of arm would have to be long enough to reach all the panels. None of the rovers arms can extend that far so they would have to have been modified. This might add weight and complexity.
Probably the biggest reason why NASA didn't put one in was the rovers were designed for 90 sol missions. Having them last 5 years is a bonus. Along the way, the Rover team has dealt with the problems that have come with extending the mission beyond the original parameters: wheels no longer work, tools no longer function, dust storms limit power usage, etc. This is one issue that they knew would eventually cause the rovers to cease functioning after a few years.
Well, there's spam egg sausage and spam, that's not got much spam in it.
The most Illustrious Council of Elders has issued an update following yesterday's Planetary Day of Celebration of Victory over the Northern Invader. K'breel, Speaker for the Council, spake thus:
When a newly-hired journalism intern implied a correlation between the invaders' movements and seasonal weather patterns, and pointed out that that the current sandstorm had begun to abate, and that the same winds that were promised to bury invaders in dust could also, on occasion, blow accumulated dust off the invaders, K'Breel, in a rare display of compassion, responded by offering him a piece of jerky made from the dried gelsacs of a recently-retired member of the Press Corps.
The Planetary Society blog has a composite picture of Spirit from two years ago and today which shows starkly just how much dust has accumulated.
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.
The two rovers were not designed to work for 90 days.
They were guaranteed to work for 90 days.
The various components were designed to work no matter what they experienced for 90 days on the Martian surface.
I suspect that they were designed for the worst possible set of circumstances for 90 days which has allowed them to operate for the much longer time in the actual environment which is more benign than the worst case scenario.
Regardless of the semantics of the 90 days, the time the two robots have been operating is still an amazing achievement and everybody involved should be very proud.
myke
Mimetics Inc. Twitter
During a day, solar panels don't produce any watts of energy. Watts are a compound unit, specifically joules per second. Joules are a measurement of energy, and what would be produced in a a time period. Watts represent the instantaneous rate of power generation.