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Opportunity Rover Arrives at Endurance Crater
Mean_Nishka writes "After weeks of driving, the Mars Exploration Rover Opportunity has arrived at 'Endurance Crater.' It's a scientific treasure trove with an extensive outcrop of layered bedrock, and scientists will have to decide whether or not to send Opportunity inside for a closer inspection without getting it stuck forever - there's more information via a Monterey Herald/AP article."
Here's what I found earlier in the article:
Hope this helps.
Mycroft
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It could very easily get stuck there. When the rover was leaving the crater that it landed in, they had a little bit of trouble because of soil slippage, and the crater wasn't all that steep.
The first point is a valid reason not send one, though I think other issues probably had more to do with it. Like what would they use it for on a water finding mission. I supose to reveal deeper layers or somthing, but really an explosive device probably isn't all that usefull on this mision, especially for trouble to get it there.
As to the second, it's not entirely true. It is possible to make all sorts of explosive device that eigther don't depend on combustion (IIRC tnt explodes not by combustion, but by 'falling apart') or contain oxidizers in the mix removing the need for atmospheric O2.
Mycroft
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. Non nuclear bombs require oxygen to explode
Bombs carry their own oxidizer. In the case of gunpowder, it's potassium nitrate. Other types of explosives use other things, including potassium chlorate, potassium permangenate, etc. There is not enough oxygen in the air to make something combustable explode on it's own, it will just burn.
Even the old school fuses you see in cartoons going to dynamite have their own oxygen source (usually a string doped with gunpowder). This is why they will burn underwater, or even in an atmosphere without water.
The problem with the rovers carrying explosives, is that the explosives would need to be buried for them to have an effect. Just dropping a stick of dynamite on the surface would cause very little disruption.
When I was like 16, I worked at a gas station. There used to be this guy that came in with a silver van that said Kaboom! on the side. Turns out, he ran a demolitions company. He'd always sit and chat with us about his destructive creations. It almost seemed like he liked his job a little too much. Nevertheless, he was always interesting to BS with.
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Ahhh, sorry I misunderstood your question. Odds are they don't know yet. It will take time to gather evidence. And considering thier discussing whether or not to enter the crater at all, I would assume they don't have any significant evidence yet.
Mycroft
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I believe the expected lifetime of the rovers expired some time ago, and NASA is lucky they are still operational. Then again, NASA seems to have a pretty good track record in this area- Voyager 2 and the Hubble Telescope are both far beyond their projected life spans and are still returning information.
I'm aware that a lot of explosives carry their own oxygen. That doesn't mean they don't require oxygen to explode.
I guess I was thinking you would ideally use a bomb that can use atmospheric oxygen, but maybe they don't really exist.
You can probably make a bigger crater by crashing the craft it came in anyway.
As JPL stated here they think they may get about 250 sols out of these rovers, which is the approved duration of the extended mission (of course, I'm sure they'll keep extending it until they die, but there is a ten day communications blockage from the sun at about that time).
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Of course, this doesn't work if something unexpected happens like lots of soil slippage or a rock giving way (that would have to be one large rock). The rovers are programmed to go around rocks, not over them, so the chances of it tipping over are pretty low. Soil slippage like the type Opportunity saw at Eagle crater isn't going to cause the rover to tip. It was have to be a full-on landslide.
BTW, in the spirit of great-minds-think-alike, the idea of sending a microphone to Mars was first suggested by the late, lamented Carl Sagan.
``Life results from the non-random survival of randomly varying replicators.'' -- Richard Dawkins
Of course, it's actually a $100,000 mic, but hey, that's pretty close to $0.25 in space dollars. :-)
On the subject of microphones, the Cassini-Huygens probe currently on its way to Saturn/Titan is carrying one, so that we can hear Titan. The prospect of hearing the first waves lapping against an alien shore is quite remarkable. If theres any liquid there, that is.
TheHustler
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The path I walk alone is endlessly long.
30 minutes by bike, 15 by bus.
You could always just (as I presume they will) slowly restrict operations as effeciencies wear down. (Nah, stay here today, charge batteries for a trip tomorrow)
The problem is that at some point the panels are not generating enough energy to keep the rovers hot over night, so the internal temperature of the components cannot be maintained at their operational level, and then NASA expects that they will start having component failures.
Yes, in fact they did -- some bits of metal and fabric, to study the effects of radiation and micrometeor pitting over time.
"Ain't no right way to do a wrong thing."
" and scientists will have to decide whether or not to send Opportunity inside for a closer inspection without getting it stuck forever "
Christ! The rover has met its mission objectives 100%. Its OK to take a little risk. Hell, its OK to take a _LOT_ of risk!
It is time for NASA to grow a set of balls, strap em' on, and be bold enough to really go out and explore.
If the little bastard gets stuck in the crater, it can still sit there and do in-place observations of the atmosphere, and monitor the crater over the course of whatever time the rover survives. That would still be worthwile!
Its a machine. If it croaks, oops. Move the people on and start working on the next mission.
If Opportunity exhausts the scientific possibilities at Endurance Crater, the next target, according to NASA press releases is some "etched terrain" several kilometers to the south. Presumably they would be weighing the possibility of getting to that versus the benefits of spending the rest of the mission at or inside Endurance.
Is it just me? I can think of far worse things to happen to a sophisticated geological probe than to be stuck forever in the middle of a "scientific treasure trove". The actual problem may be that Opportunity wears out before they are done looking over all the goodies.
"That is like speaking of food so appetizing that no Frenchman would eat it." -- Mark Twain
As a geologist the formations in the center of the crater look like small star dunes to me. They form when winds come from multiple directions, such as the swirling winds you would get in a crater.
If God had had a computer it would have taken him 7 months to create the earth...if he even bothered to do it at all.
By the time they got done adding a complicated bolt anchoring system, a bunch of wire, cutters, dust sweepers, extra mechanical arms, gyroscopes, and all of the other stuff people had suggested, the rover would end up weighing 50 tons and would never get off Earth. The tradeoffs in this business are merciless and if a system isn't on the rovers, it's probably because it would have replaced something more valuable.
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The problem is that at some point the panels are not generating enough energy to keep the rovers hot over night, so the internal temperature of the components cannot be maintained at their operational level, and then NASA expects that they will start having component failures.
Indeed. The swing in tempuratures is estimated to be the biggest risk. Electronic components constantly expanding and contracting due to day-to-night-cycle tempurature changes eventually works things loose and cracks stuff.
The second biggest risk is probably dust getting into everything.
Note that the rovers do have small radioactive capsules that provide some warmth, but not enough. If you put too many of those in, then you have to use more expensive launch techniques to decrease launch failure risks of spreading the radioactive stuff.
The next generation of rovers are to exclusively use nuclear cells to generate power and maintain constant tempuratures to avoid such problems. However, I expect protesters to complain.
Such issues strangely reflect the need of mammals to have a constant body tempurature. The more complex the components/functions of an animal, the more a constant body tempurature seems to facilitate that. It is less variables the complex components have to deal with. But, it requires more energy. That is why reptiles can eat less per body weight. But the flipside is that they tend to be sluggish in the cold, or at least their performance is inconsistent as different chemicals are needed at different tempuratures, sometimes leaving gaps for certain tempurature ranges.
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The rovers don't have a self-righting mechanism, but they might be able to do something with the instrument arm. NASA has done extensive testing of the rovers to determine the performance envelope.
I know the rover drivers etc, and am familiar with the hardware. The idea that the IDD could right the rover would get many a chuckle here at JPL, as the IDD is not load bearing, and has very slow motors.
The torques induced when spectrally imaging the magnets alone is enough to slow down the arm movements.
If the rover is flipped over, we lose all power but batteries, and probably break mechanical components in the process. Communications may become difficult or impossible. If/when that happens, it's over.
Would make one hell of a final pancam though, the ground a centimeter away from the PMA.
Cheers,
Justin Wick
Disclaimer: I do software engineering on the mission, I do not directly drive the rovers.
I leave it to the scientists to see this from their chair. They drove more than they expected, past the "warranty" of the rover, to get there. From now on, all is gravy. From their vantage points, they can figure out if there is anything even remotely around which would make it not worth the risk. You gotta die sometime. Might as well be doing something useful.
Don't worry, the scientists are well aware of the cost/benefit tradeoffs associated with this... They are all very excited about going into the crater etc, however the crater is very dangerous.
After much discussion with various individuals, it's my best guess that we will decend, after much remote sensing, into a shallow part of the crater, look at some outcrops, and then climb back out, rather than getting stuck in the bottom with nothing new to image.
But this is not yet official.
Cheers,
Justin Wick
Disclaimer: I'm a software engineer on the mission, I don't drive the rover or make any of the decisions about where it goes.