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Mars Winds Clean Spirit's Solar Panels Again
Titoxd writes "In a blast from the past, NASA reports that Spirit's solar panels have received a much-needed cleaning courtesy of the Red Planet. The report states, 'The cleaning boosts Spirit's daily energy supply by about 30 watt-hours, to about 240 watt-hours from 210 watt-hours. The rover uses about 180 watt-hours per day for basic survival and communications, so this increase roughly doubles the amount of discretionary power for activities such as driving and using instruments.'"
. . . don't forget to pack the broom.
"Who controls the past controls the future. Who controls the present controls the past." -- George Orwell
That's much better than NASA's alternative plan of sending a Squeegee Kid to do the job.
Yep - there are pools at JPL and Caltech. Go Beavers!
Did you ever wake up in the morning, with a Zombie Woof behind your eyes? -- FZ
Rule 1 of engineering: Underestimate your estimates.
The thing was designed to run for years. However they gave it a 90 Day limit to save their butts if it breaks in 85 days. as well the mission spec was for 90 days, so they made sure it would last that 90 days as much as possible. It is not like you going to put up a million dollar probe and skimp on parts. You are going to make it as robust as possible as estimating 90 days of operation in the unknown is quite hard.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
Weight = money. At $10,000 per pound, it would have been a waste of money for a vehicle designed to last only three months.
If the vehicle were designed to last five years, it might be a different story.
Maybe next time, NASA should include some type of cleaning devices,
This comes up every time the rovers are mentioned. Here is a detailed explanation why there are no wipers, or any other cleaning device, on the rovers.
We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
My computer uses nearly that much power under full load, and it doesn't even have to move!
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And of course, the scene from the TNG episode "Relics":
"Starship captains are like children. They want everything right now and they want it their way. The secret is to give them what they need, not what they want."
"I told the Captain I would have this diagnostic done in an hour."
"And how long will it really take you?"
"An hour!"
"Oh, you didn't tell him how long it would really take, did you?"
"Of course I did."
"Oh, laddie, you have a lot to learn if you want people to think of you as a miracle worker."
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Not 240 watts; 240 watt-hours. With 24.6 hours per Martian day, that's about 9.75 watts average consumption.
Cruise is something of an exaggeration... they've gone 13 miles in 5 years, put together. The Lunar Rover missions each went longer than both combined in 3-4 hours, at top speed they'd pass the rovers within the first hour. Semi-stationary crawlers is a more accurate description, but of course they've been loaded up with scientific equipment rather than for showing off.
Live today, because you never know what tomorrow brings
Only on Slashdot can a post that confuses power (watt) and energy (watt-hour) be modded +3 Interesting.
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
NASA probably has a good idea. Published estimates were likely wrong on purpose from the start to give them the opportunity for more media coverage and subsequently budget opportunities.
Not exactly. Estimates are based on worst case scenarios. What would have been the public's reaction if NASA had said that the rovers would last 1 year but they only lasted 6 months? NASA guidelines require that when something is supposed to last x months/years, then it's engineered such that it will last that long, no matter what. Specifying mission requirements is actually a tricky problem for the scientists on a mission because you want the most possible science that fits within a budget and that will last for as long as you say it will last. And usually the only way to convince NASA that something will last is if you add in backup systems. With new, expensive technology this becomes even harder.
So yes, the rovers were conservatively estimated to last 3 months. I'm sure the scientists on the mission expected that they would last longer, but 3 months was a good benchmark that provided a good amount of science for a reasonable cost. Everything else has just been icing on the cake (and in this case, a lot of icing). Personally, I think they did a great job and cannot fault them at all.
(I am a grad student working on a NASA mission and have seen a bit of how this process works)
How dare you inject a useful, explanatory article into the armchair quarterbacking? I don't know where you think you are, but this is [i]Slashdot[/i], kid. Take that stuff somewhere else.
Oh, you're not stuck, you're just unable to let go of the onion rings.
Exactly. "Designed to last 90 days" presumably means something like "Designed to have a 95% chance of lasting 90 days". Which probably means it has a 90% chance of lasting 180 days, an 80% chance of lasting 360 days...
I don't know what confidence threshold NASA uses, maybe more than 95%. So the 5 years these lasted is lucky, but not so completely off the charts as it might seem.
The Mars Science Lander is two years late and a billion dollars over budget because it has developed lots of new technology. It was supposed to launch during the 2009 optimal planetary configuration, but will have to wait until the 2011 one. The next lander uses a nuclear source and rocket landing instead of airbags. I'm a little fearful all the new stuff may not work as planned. I am also fearful NASA budgetary troubles may still kill it.
Anyone interested in the Mars Exploration Rovers' mission should check out Mars And Me, the unofficial diary of a Mars rover driver. Scott Maxwell is blogging his daily work at JPL exactly five years later. A very interesting and well-written look at the day-to-day operations of a truly amazing scientific expedition.
How about we all stop thinking that we have better ideas than the guys who built these incredible pieces of machinery? /. we have a bunch of armchair engineers believing they could do better?
I mean the designers built two rovers that had to survive a launch from earth, months in deep space, a bouncy landing on another world, and then operate correctly with a 10 minute (Or longer) radio delay.
That is an incredible accomplishment! Then for it to continue to operate for YEARS! I am in awe of the designers.
Now here on
Do you honestly believe that the same people who built these incredible machines didn't think of a solar panel wiper? A can of compressed air? A fan? A compressor?
To the designers: If any of you are reading this. My hat is off to you. Well done!
If I were God, wouldn't I protect my churches from acts of me?