How the Curiosity Rover's Nuclear Battery Works
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How the Curiosity Rover's Nuclear Battery Works
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Re: How the Curiosity Rover's Nuclear Battery Works
#2Wow, that's super cool. I wonder if this technology is being used on any earth-based applications? If not, I'm assuming there are harmful side effects that don't necessarily affect the space missions. I'd like to learn more about the negatives of this technology basically.
Re: How the Curiosity Rover's Nuclear Battery Works
#3Wow, that's super cool. I wonder if this technology is being used on any earth-based applications? If not, I'm assuming there are harmful side effects that don't necessarily affect the space missions. I'd like to learn more about the negatives of this technology basically.
There's probably a radiation issue that wouldn't make it suitable for close to human contact. I wonder how much energy the rover needs to move around since the gravity there is considerably weaker.
Re: How the Curiosity Rover's Nuclear Battery Works
#4Wow, that's super cool. I wonder if this technology is being used on any earth-based applications? If not, I'm assuming there are harmful side effects that don't necessarily affect the space missions. I'd like to learn more about the negatives of this technology basically.
Sometimes used in earth-based applications too. See http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen....
Re: How the Curiosity Rover's Nuclear Battery Works
#5Wow, that's super cool. I wonder if this technology is being used on any earth-based applications? If not, I'm assuming there are harmful side effects that don't necessarily affect the space missions. I'd like to learn more about the negatives of this technology basically.
If this is the same tech I remember, Soviet Russia used them a lot for far-flung lighthouses that couldn't be easily refueled. Many of them are still out there, or have been stolen, vandalized, stripped of metal by unwitting thieves, spreading hazard all around. One was even found underwater.
edit: links:
http://bellona.no/bellona.org/english_import_area/internatio...
http://englishrussia.com/2009/01/06/abandoned-russian-polar-...
Re: How the Curiosity Rover's Nuclear Battery Works
#6How much power does the device generate? How much will it generate in 14 years when it is "expended"?
Edit: Initially 2 kW of thermal power and 125W of electrical power, falling by only 20% after 14 years. https://en.wikipedia.org/wiki/MMRTG#Design_and_specification...
Re: How the Curiosity Rover's Nuclear Battery Works
#7Wow, that's super cool. I wonder if this technology is being used on any earth-based applications? If not, I'm assuming there are harmful side effects that don't necessarily affect the space missions. I'd like to learn more about the negatives of this technology basically.
For a short while they were used in implantable pacemakers as 'lifetime' power sources[1]
The main issue is that they're really rather inefficient. The efficiency of the thermocouple at converting thermal->electrical is only about 5-10%, and combined with the cost of shielding, expense of the radioisotope to begin with, and security/safety considerations, they're really only suitable for niche aerospace/defense applications.
Edit: I was curious if anyone had considered a stirling or other heat-engine driven by decay heat, and found https://en.wikipedia.org/wiki/Stirling_Radioisotope_Generato... which looks like it can hit 20+% efficiencies. The downside is that unlike thermo-electric/Seebeck effect converters, they have moving parts that could be a threat to reliability, which is the major issue when you're a planet away from the nearest repair tech.
[1] https://www.orau.org/ptp/collection/Miscellaneous/pacemaker....
Re: How the Curiosity Rover's Nuclear Battery Works
#8How much power does the device generate? How much will it generate in 14 years when it is "expended"? Edit: Initially 2 kW of thermal power and 125W of electrical power, falling by only 20% after 14 years. https://en.wikipedia.org/wiki/MMRTG#Design_and_specification...
According to Wikipedia, 125 watts when it was launched, down to about 100 watts in 14 years.
The JPL guys claim that the RTG is really just a trickle charger for the batteries that actually handle the load -- which likely has transients that the thermocouple in the RTG couldn't handle.
I don't know the lifetime of the lithium-ion battery pack but I'm guessing it'll degrade way before the RTG power decreases below the point where it can effectively charge the battery.
Re: How the Curiosity Rover's Nuclear Battery Works
#9Wow, that's super cool. I wonder if this technology is being used on any earth-based applications? If not, I'm assuming there are harmful side effects that don't necessarily affect the space missions. I'd like to learn more about the negatives of this technology basically.
There's probably a radiation issue that wouldn't make it suitable for close to human contact. I wonder how much energy the rover needs to move around since the gravity there is considerably weaker.
Rover mass is same on Earth or Mars. So acceleration costs the same. Low gravity also means less friction with the ground, making it somewhat harder to move on Mars.
Climbing hills would be easier on Mars.
Re: How the Curiosity Rover's Nuclear Battery Works
#10Many people here in the far north have extensive solar setups and live completely off-grid. Unfortunately in winter, we only get ~4 hours of sunlight, and it's a pain to sweep snow off the panels every day at ~ -30C to -40C
We don't get much wind, and rivers are only liquid for ~4-5 months, so wind and hydro are not popular.
I've been investigating commercial thermoelectric couplings as a source in the winter. Everyone has a BIG wood stove burning 24x7 for ~6 months. My best research shows it shouldn't be hard to see +400C on the top surface of the stove. My plan is to have a radiator outside, run anti-freeze in the system and get an approx 400 deg C temperature drop.
Now, my interest is peaked in this approach from NASA. I wonder how long it will be until I can buy or build such a thing?