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NASA's Perseverance rover sends stunning images

bbc.com

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Re: NASA's Perseverance rover sends stunning images

#91

Post by souprock »

marshmallow_12 wrote: post #52
11thEarlOfMar wrote: post #44

Stupid question, but where is Perseverance's energy source? Answer: Plutonium It powers a Multi-Mission Radioisotope Thermoelectric Generator. The plutonium decays at a few % per year, so that means it should be able to bring Elon a sandwich when he lands. https://mars.nasa.gov/mars2020/spacecraft/rover/electrical-p...

a glowing green sandwich covered in red sand. But seriously, this stuff is powering those voyager probes 40 years later. Which makes me ask: why do we have to send there technologies 10 billion miles away to make them work? Why can't my fridge be powered this way?

We used to power pacemakers this way. There might still be a person with plutonium inside.

Re: NASA's Perseverance rover sends stunning images

#92

Post by hanniabu »

asdff wrote: post #49
hanniabu wrote: post #29

Earlier quoted context omitted.

What's difficult about it?

Multiple clicks to get to the full resolution image. 50 thumbnails able to be viewed at a time, many uninteresting to lay people (solid gray screen, dozens of repeated images of of a portion of the rover itself, etc), for the monumental task of sifting through the 6407 images the rover has transmitted so far in mere days. Wholly unusable in a few months I imagine.

Maybe over the weekend if I can carve out a few hours I'll put together an open source site and share here.

Re: NASA's Perseverance rover sends stunning images

#93

Post by almyk »

rsj_hn wrote: post #79
azernik wrote: post #47

Earlier quoted context omitted.

The helicopter hasn't flown yet - they put it down on the ground, and they're going to run it through a lot of remote checks before flying it. IIRC it's gonna be a month or two before first flight.

Thank you for this! Do you know of a source on the net for a simple timeline of when X will happen?

This is not a timeline, but it states the objectives of the helicopter and contains a check list of them.

https://mars.nasa.gov/technology/helicopter/

Re: NASA's Perseverance rover sends stunning images

#94

Post by matheusmoreira »

marshmallow_12 wrote: post #52
11thEarlOfMar wrote: post #44

Stupid question, but where is Perseverance's energy source? Answer: Plutonium It powers a Multi-Mission Radioisotope Thermoelectric Generator. The plutonium decays at a few % per year, so that means it should be able to bring Elon a sandwich when he lands. https://mars.nasa.gov/mars2020/spacecraft/rover/electrical-p...

a glowing green sandwich covered in red sand. But seriously, this stuff is powering those voyager probes 40 years later. Which makes me ask: why do we have to send there technologies 10 billion miles away to make them work? Why can't my fridge be powered this way?

Surely it would be a horrible idea to distribute radioactive materials to the general population.

https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident

Re: NASA's Perseverance rover sends stunning images

#95

Post by perardi »

nitrogen wrote: post #74
AnimalMuppet wrote: post #54

Earlier quoted context omitted.

What's powering Voyager is a plutonium pile. Pretty sure you don't want that in your fridge. 10 billion miles from me? Sure, knock yourself out. 10 feet from me? No way.

AKA "Not In My Back Yard." So the question stands and extends to include this: "why not?"

People are probably going to answer “safety”.

But it’s also hideously expensive. Plutonium is, apparently, one of the safer ways to build these things, because it is easy to shield, and the power density is good. But plutonium, as it’s not naturally occurring, is stratospherically expensive.

https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...

Re: NASA's Perseverance rover sends stunning images

#96

Post by waheoo »

khuey wrote: post #81
AnimalMuppet wrote: post #54

Earlier quoted context omitted.

What's powering Voyager is a plutonium pile. Pretty sure you don't want that in your fridge. 10 billion miles from me? Sure, knock yourself out. 10 feet from me? No way.

The radiation emitted by plutonium 238, which is what's found inside RTGs, is easily shielded by essentially any solid material. The real reason you don't want an RTG powering your fridge is that it costs on the order of one million dollars per watt.

Economies of scale would surely change that though?

Re: NASA's Perseverance rover sends stunning images

#97

Post by Balgair »

oso2k wrote: post #83
shkkmo wrote: post #69

Earlier quoted context omitted.

The 8 figure price tag for a RTG makes consumer use uneconomical.

More than likely, 99% of that cost is the container and the apparatus to make use of its energy. [0][1] [0] https://www.thoughtco.com/what-is-most-expensive-element-606... ). [1] https://www.sciencedirect.com/topics/earth-and-planetary-sci... .

Plutonium-238 can only be made via Uranium-238. Per the Seaborg process, you must bombard U-238 with deuterons to get Neptunium-238, which then further decays into Pu-238. The Pu-238 then decays into U-234 with a half life of ~88 years. U-234 has a half life of ~200,000 years, btw.

It is very unlikely that the production of Pu-238 would cost less to produce than the container and the apparatus that harvests the energy.

Let alone the issues with the waste products of U-234 hanging about in the kitchen or basement. If you think climate change is bad as is, add in what people will do when faced with surplus uranium waste removal costs.

https://en.wikipedia.org/wiki/Plutonium-238

Re: NASA's Perseverance rover sends stunning images

#98

Post by extrapickles »

shkkmo wrote: post #69
marshmallow_12 wrote: post #52

Earlier quoted context omitted.

a glowing green sandwich covered in red sand. But seriously, this stuff is powering those voyager probes 40 years later. Which makes me ask: why do we have to send there technologies 10 billion miles away to make them work? Why can't my fridge be powered this way?

The 8 figure price tag for a RTG makes consumer use uneconomical.

The reason for that high of a price tag is that the engineering costs are spread over a very few units. If they made 100,000 of them, the costs would be much closer to the materials cost.

Re: NASA's Perseverance rover sends stunning images

#99

Post by mojomark »

What are the "dark spot anomalies" that appear to be floating in the air in some images (1, 2)? Dust on the camera lens? I've never looked at any rover images so I assume someone knows.

Also, whay are the images fairly low resolution compared to a phones camera. Does it have to do with image data transmission error?

Finally (then I'll shut up), when do we get to see the stereo images? I want to see these on my Vive.

1.) https://mars.nasa.gov/mars2020/multimedia/raw-images/NLE_000...

2.) https://mars.nasa.gov/mars2020/multimedia/raw-images/SI0_001...

Re: NASA's Perseverance rover sends stunning images

#100

Post by briga »

waheoo wrote: post #96
khuey wrote: post #81

Earlier quoted context omitted.

The radiation emitted by plutonium 238, which is what's found inside RTGs, is easily shielded by essentially any solid material. The real reason you don't want an RTG powering your fridge is that it costs on the order of one million dollars per watt.

Economies of scale would surely change that though?

Plutonium is fairly rare, so I'm not sure it could be scaled up easily, even if there was a demand for it. Not to mention we probably don't want the raw material for nuclear bombs to be inside easily accessible home appliances...
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