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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."
. 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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The've actually done quite a bit of testing on rover slippage on inclines with and engineering prototype here and have a chart showing up/down angles vs. slippage. elswise when they tell it to go forward 15 meters, it may stop at 12 or go past to 17 if the weels slip (the rovers rely on sensing wheel rotation to calculate distance traveled) they've been refining this test data (which they found alot closer to reality than they had hoped) with actuall measurements since then.
Thier data indicates that at about 25 degrees an uphill climb becomes impossible because of the slippage. so all they need to do is find a usuable slope under 25 degrees in angle.
Mycroft
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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 rovers can reduce the angle of a slope by going diagonally up a slope. In a conical crater, a rover could traverse the sides in a spiral pattern to reach the top. Assuming it doesn't slip down as much as it is trying to move up.
The safest route is straight up and straight down. A roll over is more likely when going sideways on a slope.
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.
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.
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.