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Mars Rovers Return to Exploration
inkslinger77 writes "The two Mars rovers that have been carefully conserving critical power supplies since June, when the summer dust-storm season began on the red planet, are now springing back to work as the storms subside.
Typically, the solar panels on each rover produce about 700 watt-hours of electricity per day — enough to light a 100-watt bulb for seven hours, according to NASA. But this year's dust storms reduced that to as little as 128 watt hours per day. When daily power generation is down to less than 400 watt-hours, the rovers suspend their driving on the planet and stop using their robotic arms, cameras and other instruments.
But they are back in action now!"
Hope they're not Li-ion.
They say the first thing to go is your penis. Well, it's either that or your brain. I forget which...
I don't think you need NASA to say that - I think I can confirm that 700 watt-hours will power a 100-watt bulb (or device) for 7 hours. furthermore, improving on NASA, I can also say that it will power 7 100-watt bulbs for 1 hour, or 1 700-watt bulb for an hour.
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It runs and runs and runs...
The dust storm even kind of polished it.
Go rover go!
"Hannibal's plans never work right. They just work." Amy/A-Team
The issue of whether or not to put some sort of dust-clearing device on the panels was examined critically and decided on early in this project. In short: they didn't know what dust storms would do to the panels; it turns out they tend to remove dust. Several options for dust clearing were considered -- wipers, electrostatic techniques, peel-away plastic, and probably others I've forgotten. All of them would have *probably* worked, and all of them would have taken up space and weight. Essentially it came down to choosing between dust removal and an instrument. Faced with that decision, they decided that better quality, more complete data was more interesting than having the rovers run longer.
Of course, they got lucky, and the dust storms seem to clear dust off the panels. So there was even less need for dust-clearing than they thought there might be.
It doesn't make much difference. Phoenix is on its way and MSL is being prepared for launch in 2009.
Shame on me, but this is the first time I visited the mars rover website. It struck me as slightly odd that NASA researchers call the Martian Solar Day the sol.
Anyway, for those similarly bemused and/or further intrigued, here is the explanation of Mars Solar Time as Adopted by the Mars24 Sunclock
shooting is not too good for my enemies
If mankind ever makes it to Mars in the flesh, I hope they bring one back and give it a medal or something.
Maybe mount a plaque at the point where it 'died' on Mars as well.
Fortunately they are not into consumer electronics. Otherwise there'd be a DRM on these rovers, one they would have retired 3 years ago in a cruel, wanton act of planned obsolescence.
700 watt-hours per day
Since a watt is just a short way of saying one joule per second, this means
700 joules per second per hour per day
Do NASA really do their energy computations in this unit? Given their past problems getting to grips with the metric system, perhaps they might.
Surely it would be clearer to say 'the rover's solar panels have an average power output of about 29 watts'. Anyone could see that this is enough power to run a 100 watt lightbulb nearly one-third of the time.
-- Ed Avis ed@membled.com
Are you kidding? These rovers are functioning way beyond their mission parameters. They've collected more data than anyone expected. We've gone from "What if there's water on Mars" to "How much water is there on Mars?". The rovers survived a Martian dust storm! Martian dust storms have been known to cover the entire planet.
Let's put it this way. If your car was as well-designed and resilient as these rovers it would run on empty for 100 miles, drive up mountains, and review your tax returns.
I grew up in a coal mining area of Illinois. The worlds largest shovel (Marion 6360) was in the mine where my dad worked...and it used the same crawlers that NASA made for the space shuttle. Down at NASA, they have the thing crawl out on a carefully leveled bed of pea gravel....but down in the mines, they had some mats to lay down, but the crawlers would still crunch over stuff. Apparently, when some of the NASA people came up to look at how the shovel was doing on their crawler system, they were utterly horrified at the conditions...not one of them thought it possible for the crawlers to perform in half so "bad" of conditions and still work for any amount of time. The crawlers worked all the way till the shovel burnt in the early 90's and the thing was scrapped (an oil fire hot enough to split open the inches thick steel skin of the sucker)...
Why are you describing to slashdotters, 700 watt-hours will light up a 100watt bulb for 7 hours? Is it that easily imaginable? Should use very precise engineering descriptions like, four football fields long or as big as a refrigerator or something. The most descriptive way to describe 700 watt-hours would be something like the energy spent by a senator tapping the restroom stall floor with foot over his entire three term career or the energy used by a /. mod marking 8324 posts as trolls, flamebaits and underrated.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
We as software developers here should take note of this. The code you're writing and putting into production has the potential to last for decades. For example, out of college my first programming job was for Mutual of Omaha. They had lots of code that was written in the late 1960s in Assembler or in (gag) COBOL. Well, although someone like me would have loved to have rewritten those systems, it was not happening. Then, take another point. I myself wrote a large system for them that--according to friends who are still there--and that system has not been changed much since then. So, folks, the point is this: you write a lot of applications. Some won't survive a year. Others... they may be doing their job in twenty years. Machines wear out but--properly designed and maintained--software never does. Bravo to Spirit & Opportunity and the teams that built those kickass pieces of hardware/software.
Sigh. It's practically obligatory when you're talking about science (at least in the States, how about other countries?) to dumb it down. At least they didn't say how many ping-pong balls the rovers could carry if they were hollow.
And at least we aren't to the point of saying how many angels can dance on a rover's solar panel, or somesuch. Yet.
Hail Eris, full of mischief...
E pluribus sanguinem
"700 watt-hours of electricity per day -- enough to light a 100-watt bulb for seven hours, according to NASA"
Do you really have to be a rocket scientist to figure that out?
Q: Why do NASA engineers buy their shoes much too big?
A: They think their feet are one meter long.
When we put our minds to it , it gets built in china.
This package Does Not Contain a Winner
In the space business, if you have hardware on mars, it's already magnitudes better than anything newly developed that hasn't launched yet. Abandoning an old project for a new one risks the new one not making it there successfully. Far better to use what you have as long as you can. It it ain't broke....
inkslinger77
narramissic
jcatcw
If it's all OK and everything with the corporate ownership of Slashdot to be played by IDG, I suppose that's their business, but one would hope that they are actually getting PAID for being part of IDG's advertising program. And of course there should be disclosure so that visitors to Slashdot realize they are reading advertisements and not an article submitted by a "real" user...
If you want news from today, you have to come back tomorrow.
Slashdot is able to reproduce an article twice per week, that's close to a dupe in about 3 days, according to Nasa. http://science.slashdot.org/article.pl?sid=07/09/0 3/0154202
This is a concern, but NASA considers the work the rovers are doing valuable enough to keep funding it.
NASA's budget for 2007 provides $85 million for rover operations, communications, and data processing. Obviously that's a non-trivial amount (roughly enough to employ 350 people full-time, standard cost ratios), even compared to the $820 million spent on designing, building, launching, and operating for the first year.
For comparision, Hubble is receiving $340 million this year. The entire NASA budget for Mars exploration for 2007 is about $700 million. Almost half of that goes towards building the 2009 Mars Science Laboratory rover. The rest is divided between the Spirit and Opportunity, Mars Global Surveyor (which died a couple months ago), Mars Odyssey (orbiter), Mars Reconnaissance Orbiter, the US contributions to Mars Express (orbiter), Phoenix Polar Lander (lander, en route), and a Scout-class mission scheduled for 2011.
* My numbers came from NASA's 2007 budget request. Some of them were changed for the actual allocation.