Without Plutonium, Deep-Space Probe Missions May Sputter Out

cold fjord writes with this excerpt from Wired: "Most of what humanity knows about the outer planets came back to Earth on plutonium power. ... The characteristics of this metal's radioactive decay make it a super-fuel. ... there is no other viable option. Solar power is too weak, chemical batteries don't last, nuclear fission systems are too heavy. So, we depend on plutonium-238, a fuel largely acquired as by-product of making nuclear weapons. But there's a problem: We've almost run out. 'We've got enough to last to the end of this decade. That's it,' said Steve Johnson, a nuclear chemist at Idaho National Laboratory. And it's not just the U.S. reserves that are in jeopardy. The entire planet's stores are nearly depleted. ... what's left has already been spoken for and then some. ... Political ignorance and shortsighted squabbling, along with false promises from Russia, and penny-wise management of NASA's ever-thinning budget still stand in the way of a robust plutonium-238 production system." The plutonium shortage has been deepening for a long time, leading to some creative solutions. The Wired article alludes to the NASA project underway to create more, but leans toward gloom.

Comments

Re:Why are nuclear fission systems too heavy?

[mark-t]

Mass doesn't disappear just because something is in outer space. That mass carries with it a certain amount of inertia, and the heavier something is on earth, the more energy will be required to manipulate it with any kind of acceleration, even in space.

Re:Why are nuclear fission systems too heavy?

[fuzzyfuzzyfungus]

Launch price.

Shoving something out of ye olde gravity well is always expensive, if you go over the weight/size limit of one of the reasonably-commodified launch systems, things go from 'expensive' to 'heroically expensive'.

Depending on exactly what trajectory you have in mind, a more massive craft may also require more fuel/more powerful thrusters if you are making any course corrections along the way.

Re:112 tonnes enough?

[compro01]

That's the wrong kind of Plutonium. RTGs need Plutonium-238. That stockpile is Plutonium-239, 240, 241, and a bit of 242.

Re:Why are nuclear fission systems too heavy?

[CrimsonAvenger]

I don't know anything about them, but I have to ask why anything is too heavy in space? Is it too heavy when assembled on earth?

A very long time ago I was in the Navy, sailing about in a nuclear submarine.

The power plant of that submarine outmassed the ISS.

Re:Voyage To The Bottom Of The Sea.

[RevDisk]

Tapping undersea cables.

Re:Upside

[Baloroth]

Pu-238 isn't usable for nuclear weapons. The only use to which it is put is power generation. The only connection between Pu-238 and nuclear weapons, in fact, is that weapons production facilities naturally make good production facilities for Pu-238.