NASA's Plutonium Supply Dwindling; ESA To Help

astroengine writes "NASA's stockpile of the plutonium isotope Pu-238 is at a critical level, causing concern that there won't be enough fuel for future deep space missions. Pellets of Pu-238 are used inside radioisotope thermoelectric generators (or RTGs) to generate electricity for space probes traveling beyond the orbit of Mars — solar energy is too weak for solar arrays at these distances. Blocked by a contract dispute with Russia to supply Pu-238 and the US Department of Energy that has not been granted funds to produce more of the isotope, NASA lacks enough of the radioisotope to fuel the future joint NASA-ESA mission to Europa. However, the head of the European Space Agency has announced that they have plans to commence a new nuclear energy program to alleviate the situation."

Comments

NASA had another option in 1981

[PinkyGigglebrain]

Maybe they could use a Radioisotope Photoelectric Generator instead, at least for power, and save the Pu238 just for heating. From my understanding of it, limited since the only article (from 1981) I've ever read about it was the one I linked to, a RPG can use any gamma ray emitting isotope and will have full power for a period equal the half-life of the isotope used. And IIRC there are still several reactors in the US that can generate isotopes.

Never heard anything more about it, anyone else know more?

Re:NASA had another option in 1981

[PinkyGigglebrain]

Good point, but considering that the electronics are alerady radiation hardened against gamma ray, alpha particles and cosmic rays of much higher power I would really be surprised if much extra shielding would be needed. From another article I came across after posting it mentions that by selecting the right isotope its possible to get useful power and only need a .5cm lead shield for it to be safe around people. Since it would be in space you might be able to just shield the probe side of the RPG.

I'm sure that given some thought a workable solution could be found. I'd still like to know if anyone has heard of any work being done or did it get buried for some reason?

Re:Missed Opportunity?

[modecx]

That in itself doesn't say very much, does it?

Have you ever seen a typical home that hasn't been touched since the late 40's-50's? It had a refrigerator, a radio everyone huddled around, a single light bulb and one outlet in each room (there being very few rooms to begin with), if you were fortunate--two outlets if you're very lucky. They didn't have central air, or big screens TVs and computers humming along all day, burning through thousands upon thousands of kWh.

I see that 10% number float around from time to time. Don't know where it comes from, or if it's remotely accurate at all--but if I had to guess: should we undertake *ALL* of that energy research and weapon building today, it would be dwarfed compared to the country's power bill for A/C alone.