I have a confession to make. I don’t know squat about nuclear power.
I don’t know if nuclear fission is really safe, if we can deal with nuclear waste in a responsible way, if nuclear fusion can ever be made viable in anything by a hydrogen bomb.
And yet I’m a huge advocate of nuclear power. Why? Because I think it’s freakin’ cool. I think it would be so cool if our society ends up running on the power of atoms first formed in exploded stars from billions of years ago. I think it would be amazing if the power of those same stars were harnessed here on Earth. Every kid learning about our power grid would in turn find out about the secrets of atoms and stars, and the world would be a better place.
I’m also a huge fan of space travel. I am a child of Apollo, born in the late sixties. Some of my earliest memories are watching astronauts on live TV from the Moon. There was a book in my kindergarten classroom that I’ll never forget, a picture book all about Apollo 11, this tiny, spidery lander heading toward a barren landscape, while the faraway white capsule circled overhead. I remember Michael Collins going on Mr. Rogers to talk about why he had to stay behind while his friends walked on the Moon.
I remember putting on my winter coat in the middle of the summer, because I thought it looked like a spacesuit, and pretending to land and walk on the Moon. And I remember eating Push-Ups (best ice cream ever) and then turning the tube, plastic pushing wheel, and plastic stick into a rocketship and flying through the universe in my back yard.
So naturally, when nuclear power and space travel come together, I can’t resist it.
Remember the story of how we know that the helium here on Earth came almost entirely from nuclear decay? It’s because almost every bit of helium we have is helium-4, and helium-4 is made quite easily in alpha decay. The other isotope, helium-3, is almost completely absent from the Earth. But it’s not like that in the Sun.
The Sun makes both helium-3 and helium-4. And it fires both away from itself as part of the solar wind. Atoms of helium-3 streak from the Sun and fly all over the Solar System. Any that impact the Earth are quickly lost, as our atmosphere buffets the speeding particles, slowing them down until they finally drift off and out of the atmosphere.
But the Moon has no atmosphere. Helium-3 that smashes into the Moon has a chance to stay there, especially if it gets trapped in the loose, powdery rocks found on the Moon called regolith.
Scientists estimate that there are over one million tons of helium-3 embedded in the regolith of the Moon, compared to maybe a few hundred pounds of helium-3 to be found anywhere on Earth. So what’s the big deal?
The big deal is this. Nuclear fusion – the technology that’s twenty years away and always will be, as the saying goes – combines deuterium (hydrogen-2) and tritium (hydrogen-3) to make helium-4 and energy. But it also makes lots and lots of neutrons. Neutrons are hard to handle, carry away valuable energy, and also make the surrounding walls radioactive over time. This is nothing like the radioactivity problem of nuclear fission, but it is still a concern.
If we replace tritium with helium-3, the neutron problem disappears. Fusion between deuterium and helium-3 produces helium-4 and a proton, and that proton can be used to make electric current. Fusion with helium-3, so the scientists say, can be 70-80 percent efficient, and eliminate the need to replace radioactive container walls every few years.
So all we have to do is go to the Moon, harvest the helium-3, bring it back to Earth in huge quantities, (oh, and build a working nuclear fusion reactor), and voila! Our energy problems are solved!
Well, you’re right to be skeptical. If it sounds too good to be true, it probably is. But wouldn’t it be so cool? Imagine having the world powered not only by the process the powers the Sun and the stars, a process that requires us to understand matter on its most basic level, but if the fuel for that star-powered world came from space itself? What an incredible world that would be!
And that, my friends, brings us to the end of my story of helium. That’s one element down, only 91 more to go. Wait, didn’t they just discover element 118? Oh, well . . .
Thanks for reading!