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Mars Rovers Threatened By Dust Storms
mrcgran writes "Space.com is reporting a new potentially deadly weather condition threatening the Mars rovers: 'The first and largest dusty squall has reduced direct sunlight to Mars' surface by nearly 99 percent, an unprecedented threat for the solar-powered rovers. If the storm keeps up and thickens with even more dust, officials fear the rovers' batteries may empty and silence the robotic explorers forever. "This thing has been breaking records the past few days. The sun is 100 times fainter than normal. We're hoping for a big break in the storm soon, but that's just a hope." '"
They have. The problem is that the batteries also are providing power for heaters to keep the rover warm during the night. They probably won't (especially the batteries) survive a deep-freeze to -40C, so when sun starts shining again there may be too many things broken to start the rover up again.
So, its not that the battery won't come alive again later. Its that the cold will do serious damage to the electronics on board. Without power, there's no way to keep them warm. Nights on mars go well below -25C (in the winter, the southern hemisphere can get as cold as -120C).
From TFA:
The difference being that almost no light for too long of a period of time, not allowing the rovers to keep warm. They've always used batteries & solar power to keep the circuitry just warm enough to keep them from being damaged. Without that warmth, circuits can crack.
(2) if there is sand on the solar panels, you can't get power to wipe the sand off
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For some reason there ain't no method to wipe the sand off, apparently that's one reason why they thought they would last only 3 months.
Why no wiper is beyond me though.
I don't think so. There are no extra-terrestrial rovers that have lasted 90 days that I remember. One Soviet lander lasted 20 seconds on the surface. Sojourner lasted 83 days. If you know of any counterexamples, please let me know. Otherwise, your explanation is implausible because one year or three years is far, far longer than anyone has managed and is unrealistic.
The problem is that they expected the solar panels to fail due to excessive dust collection, blocking the light, and they had found no economical means to clean the panels. They got lucky when an occasional wind storm cleaned off the current rovers.
wire wrap is nice if weight is not a problem. In a launch, every gram matters, and wire wrap adds a lot of weight for several reasons. You have to have posts to wrap around, you have to use fat solid wire instead of thin traces, and the runs of wire are longer than the traces.
Size is also important. Wire wrap boxes are usually very large by comparison with a soldered PCB, especially where there are dense electronics. These rovers probably have several surface mount ICs on them, and you can't wire wrap that.
Also, correct me if I'm wrong here, but the longer the connecting traces/wires are, the more likely they are to be hit by EMI etc? So longer runs of wire, in addition to adding weight and bulk, could also invite unwanted and potentially damaging inducted power.
It appears they made all the right choices with the amount of information they had to go on and the design goals they had to meet. I can't think of any other possible way to explain the level of their success as discussed by numerous previous posts.
iirc, the rovers were scheduled for three months, and that's before ANY winters. The thing was designed to work for less than 1/2 yr, in the summer, but they engineered it with the "possibility" of surviving a winter or two. How may winters have they made it through so far? If it finally breaks, think of it like your car lasting you 40 years before you have to replace it. It owes you nothing, be happy for what you got, it's more than you deserved.
I work for the Department of Redundancy Department.
At Mars Exploration Rover Mission there is still no official statement that the Rovers are no longer operating normal. It seems that this site is not always up to date, but if I count correctly, images from the Rovers are still arriving. The last status report of Spirit is from June 2, for sols 1234-1239. The last Spirit images are from Sol 1247. The last Opportunity images are from Sol 1226. If I counted correctly, that must have been yesterday or today.
Age is compounding the problem. JPL has a good article up at http://marsrovers.jpl.nasa.gov/spotlight/20070612. html.
What you do with a computer does not constitute the whole of computing.
Actually, no. It was designed for three months. They, of course, made any changes that might make it last longer that didn't effect the budget, but they very definitely avoided any design improvements intended to lengthen it beyond 90 days, unless those improvements cost no money. The budget was very tight and many potential design improvements to make the rovers last longer were specifically rejected. (See the book by the project lead.)
The cake is a pie
Might I suggest that the engineers may have insisted very thoroughly to others that they were designing for 90 days, but really they were designing for much longer. Might I suggest this essay: Exaggerate with Extreme Prejudice.
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The next rover mission will no longer rely on solar panels. It will have nuclear reactors as the main source of power. http://en.wikipedia.org/wiki/Mars_Science_Laborato ry#Power_source/
1. Install wipers for the solar cells.
1) The wind from the storm has (once again) actually CLEARED the panels of dust.
2) The problem is that the storm is cutting out the sunlight used to charge the rovers. what would your "wipers" do, reach into the upper atmosphere and clear it out? Or perhaps they should have added an arm to hold a flashlight pointed at the solar panels. Genius!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
I believe you are confusing surface winds, which are very light, with atmospheric winds which are much faster and more then capable of blacking out the sun.. just because energy is up there, doesn't mean you can effectively harness it.
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Lunokhod-2 lasted for four months and explored 37 km in 1973.
National Geographic reported a day later that the storms are not a threat: http://news.nationalgeographic.com/news/2007/07/07 0706-rovers-dust.html.s -selling-solar.html
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Rent solar power: http://mdsolar.blogspot.com/2007/01/slashdot-user