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Old 10-31-2018, 05:19 PM
 
5,210 posts, read 8,210,851 times
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Quote:
Originally Posted by rjshae View Post
Well presumably you'd prioritize the power for a cleaning device since not much else can be accomplished if there's a dense enough dust coating on the panels. Clearing at least some of the dust off will presumably accelerate the re-activation of the other systems.

An alternative might be some type of ablative system using transparent sheets that roll up once released. That would only be useful for 1-2 cleanings, but it wouldn't need much power.
Power shouldn't be an issue for current much larger rovers considering power is nuclear. But it would be handy for landers or any other device that uses solar panels for power to operate. The idea of transparent sheets sounds like a pretty good idea. The InSight lander uses solar panels. Even the large rovers could benefit something to blast off dust. Images of Curiosity showed dust on the upper surfaces of the rover. Of more concern for such rovers would be to keep dust from causing any problems underneath, especially for the wheels. That would require more than transparent sheets though. Presumably, any habitats for future manned missions to Mars would likely utilize at least some solar panels to help supply power.
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Old 11-01-2018, 07:38 AM
 
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Quote:
Originally Posted by Dane_in_LA View Post
This is engineering, right? Two devices, both designed to operate under extreme circumstances. One failed for unknown reasons, one due to dust on the solar panels, both having outlived their expected service lives by magnitudes. Statistically, that's not a great case for sacrificing payload and adding complexity for a solar-cell cleaner subsystem. (N=2)

What JPL actually ended up doing (for Curiosity) was using an isotope thermoelectric generator.
But then the whackos decry using nuclear material.
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Old 11-01-2018, 07:39 AM
 
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Quote:
Originally Posted by NightBazaar View Post
Power shouldn't be an issue for current much larger rovers considering power is nuclear. But it would be handy for landers or any other device that uses solar panels for power to operate. The idea of transparent sheets sounds like a pretty good idea. The InSight lander uses solar panels. Even the large rovers could benefit something to blast off dust. Images of Curiosity showed dust on the upper surfaces of the rover. Of more concern for such rovers would be to keep dust from causing any problems underneath, especially for the wheels. That would require more than transparent sheets though. Presumably, any habitats for future manned missions to Mars would likely utilize at least some solar panels to help supply power.
Reminds me of what NASCAR put into place for the exterior cameras on the cars - transparent material on a spool that could be remotely cranked to clear the picture.
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Old 11-01-2018, 12:39 PM
 
Location: Seattle
2,396 posts, read 506,465 times
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Quote:
Originally Posted by markjames68 View Post
But then the whackos decry using nuclear material.
It's not wacko to be concerned about disbursement of radioactive dust in the atmosphere due to a launch failure. For example, a significant increase of thyroid cancer in children has been traced to regional contamination from the Chernobyl accident.

https://www.who.int/ionizing_radiati...ckgrounder/en/

Rockets are basically a large chemical bomb, so the intact recovery of the radioactive material is not assured.
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Old 11-01-2018, 02:43 PM
 
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Quote:
Originally Posted by rjshae View Post
It's not wacko to be concerned about disbursement of radioactive dust in the atmosphere due to a launch failure. For example, a significant increase of thyroid cancer in children has been traced to regional contamination from the Chernobyl accident.

https://www.who.int/ionizing_radiati...ckgrounder/en/

Rockets are basically a large chemical bomb, so the intact recovery of the radioactive material is not assured.
Plutonium-238 dioxide was used for power in the Mars Curiosity Rover. The amount was about 11 pounds. The 2020 Mars Rover is expected to carry about 10.6 pounds. Plutonium-238 is a Type A; it has a short distance. You wouldn't want to breath it, but it isn't able to pass through the upper skin layer of dead skin cells so it's not absorbed into the body like that. if there was an accident during launch, it's not like it's going to explode like a bomb; it's not going to turn into radioactive dust. It isn't made like that, it's in ceramic form and the amount on the rovers are a very small amounts. It's used to charge the batteries and keep heat for the instruments at operating conditions. There are other forms of plutonium that are more hazardous. Plutonium-238 is at the low end of the scale in terms of hazardous risk. Not sure why you bring up Chernobyl. You'd be more at risk of physical harm from getting a suntan. It might help to do a little research on the subject.
https://en.wikipedia.org/wiki/Curios...Specifications
https://www.technologyreview.com/s/4...-mars-mission/
https://mars.nasa.gov/mars2020/missi...ctrical-power/

Besides, the topic of the thread is: "NASA will probably dump Opportunity MER". Opportunity and Spirit rovers used solar panels. For a cost of some 2.5 billion dollars (Curiosity), you'd want to be sure it'll operate as long as possible to get your money's worth.
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Old 11-05-2018, 05:22 AM
 
Location: PRC
3,250 posts, read 3,365,783 times
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There are plenty of 'cleaning events' which have supposedly cleaned both the rovers solar panels back to squeaky-clean, so dont need any windscreen wipers on their solar panels to keep the dust off. Personally, I dont believe the so-called cleaning events, but anyway, thats what we are told. Even after major dust storms, the solar panels somehow become clean, so this one should not be a problem.

Has it actually finished yet? Have we been told anything more about it? The dust storm which they will use to dump the last MER?

If the rovers are actually on Mars, then I agree they both have lasted well past their sell-by date which speaks well for the engineering involved.
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Old 11-05-2018, 11:51 AM
 
28,638 posts, read 40,613,958 times
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Quote:
Originally Posted by ocpaul20 View Post
There are plenty of 'cleaning events' which have supposedly cleaned both the rovers solar panels back to squeaky-clean, so dont need any windscreen wipers on their solar panels to keep the dust off. Personally, I dont believe the so-called cleaning events, but anyway, thats what we are told. Even after major dust storms, the solar panels somehow become clean, so this one should not be a problem.

Has it actually finished yet? Have we been told anything more about it? The dust storm which they will use to dump the last MER?

If the rovers are actually on Mars, then I agree they both have lasted well past their sell-by date which speaks well for the engineering involved.

Once again with the dumb comments. Will it never cease?
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Old 11-06-2018, 01:17 PM
 
33,821 posts, read 17,312,451 times
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Quote:
Originally Posted by rjshae View Post
Rockets are basically a large chemical bomb, so the intact recovery of the radioactive material is not assured.
It's not that much of a difficult engineering problem to design a cask that will allow for intact re-entry and impact at terminal velocity.
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Old 11-06-2018, 10:59 PM
 
Location: PRC
3,250 posts, read 3,365,783 times
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Quote:
Originally Posted by markjames68 View Post
But then the whackos decry using nuclear material.
To me, the REAL whackos are the ones who allow nuclear energy generation - even after we realise that the waste is lethally toxic for hundreds of thousands of years and we have nowhere to store it. Currently much of it is stored above ground in dry caskets in huge storage areas. If any disaster happens, these area will be overcome and the contents will be spread about to kill off the population. Many of the caskets are 20-40 years old and rusting.

(You really need to see this) In Fukushima, they store the radioactive soil waste in huge black bags which degrade with the sunlight and split open.
The HUGE area used to store these bags of waste, many bags layers high too.

Taken from 2 trips to Fukushima by this journalist.
First trip -
Fukushima Sept 2015

and

Fukushima a second Chernobyl? second trip Sept 2016

So, I think these images speak for themselves, maybe you can reply to that.

Last edited by ocpaul20; 11-06-2018 at 11:07 PM.. Reason: add more bags
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Old 06-27-2019, 12:57 AM
 
Location: PRC
3,250 posts, read 3,365,783 times
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OK, so we have officially now dumped Opportunity after extensive 'wake-up calls' to it by the scientists. I wonder why the 'cleaning events' failed this time to clear off the dust from the solar panels.

Possibly it is 'planned obsolescence' and so my prediction has come true. What a surprise. (Well, not to me anyway)
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