Helium-3 and Lunar power for Earth reactors
"All civilizations become either spacefaring or extinct." -- Carl Sagan
When former astronaut, Harrison Schmitt, gave his talk at the Cradle of Aviation Museum about being the last crew on the moon in Apollo 17, he said something that really got my interest when he mentioned that the moon has Helium-3 which can be a great resource to commercial fusion power on Earth. Since NASA’s manned space program is no longer in existence, are we just giving this resource to the Russians, Chinese or whoever comes next trying to send a manned ship to the moon? Of course, there are the US private enterprises that are targeting space travel, but right now I only hear about getting rich people to pay in excess of $1M to fly into space or to send a man and woman to Mars. Hopefully this might be an alternative in conjunction with NASA’s expertise in manned space flight.
Schmitt’s book, “Return to the Moon” has some great points which I will outline in this article. I’d like to hear from our readers as to what they think.
This is an artist's concept of a small lunar outpost. Someday, larger lunar outposts may serve as a backup for civilization in case of a global catastrophe, like an asteroid impact or a pandemic. Image courtesy of NASA
Schmitt is a geologist (PhD from Harvard) by trade originally, so I take his insights very seriously.
Helium-3 is emitted by the Sun. Earth’s atmosphere prevents it from arriving here in any significant quantity---but Lunar soil has been absorbing it for a billion years!
Helium-3 exists in the debris layer at the lunar surface generated by meteor impacts (called the lunar regolith). Pre-Apollo knowledge told us that fusion reactions in the Sun produce helium-3. The major by-product of any helium-3 production on the Moon will be large amounts of hydrogen. Hydrogen is present at measured levels of at least 50 to 150 ppm in the Apollo regolith samples brought back to Earth.
The flux of the solar wind ions impacting the Moon per unit area varies with the quantity ejected by the Sun and their interactions with the Earth’s magnetosphere. Since the Moon has no atmosphere, unlike the Earth, these ions hit the mineral and glass particles exposed at the surface. They penetrate up to a few then thousandths of a millimeter beneath the exposed surfaces of the individual grains.
What can this do for power generation here on Earth? Current nuclear power stations are based on the nuclear fission process. This releases energy by splitting a uranium nucleus by breaking it into fragments---thereby releasing radioactivity and nuclear waste. Nuclear fusion reactors, which use the process that fuels the Sun, have the potential to replace fission reactors in the future. One type of fusion process involves fusing together the nuclei of Tritium and Deuterium to release energy and Helium in a “clean” nuclear reactor, but a drawback is a so-called “fast neutron” that is produced along with the Helium that causes energy loss and containment problems that currently prevent nuclear fusion generation.
The fusion of Helium-3 with Deuterium and the production of protons and alpha particles had been demonstrated by scientists in 1949. Scientists believe that future “clean” nuclear reactors can be based on this ‘neutronic” fusion in which Deuterium and He-3 are fused together in a reaction that releases energy and only results in normal He and a proton. The major problem is getting a supply of He-3.
Extremely small, commercially insignificant amounts of primordial helium-3 can be found in the helium mixed with natural gas and with gases emanating from the mid-oceanic vents. Amounts adequate for experimentation are available at about $1,000/gm from the processing of tritium used in nuclear weapons (Tritium decays to helium-3 with a half-life of about 12.3 years and can be purchased from the US and Russian governments.)
It is believed that the Moon has over one million tons of He-3 on its surface that can be extracted by heating the lunar dust to 600 degrees. A full Space Shuttle cargo bay could have fit 25 tons of He-3 and that could power the entire US for one year! Economists value He-3 at $3B/ton---more than enough to make it economically feasible to extract it from the Moon.
Schmitt’s book outlines the economic and technical chain that ties lunar resources to commercial fusion power on Earth with three major links:
1 Reliable low-cost payload transport to the Moon
2 competitive helium-3 based fusion power plants on Earth
3 competitive helium-3 fuel costs
The value of lunar helium-3 for fusion electrical power plants on Earth will be a function of the cost of competitive energy sources. Residual fuel oil and steam coal are future direct competitors to helium-3 for power generation. We know how their prices are rising.
There is significant interest in going to the Moon to mine He-3:
- In 2006 Russian Space Corp., Energia reported plans to establish a permanent Moon base by 2015 and to be mining He-3 on an industrial scale by 2020
- NASA in the US has plans for a base on one of the Moon’s poles, where He-3 is known to be in largest concentrations
- China plans to have a man on the Moon by 2017 to measure the thickness of the Lunar soil and the amount of He-3 present there.
I don’t hear much about He-3 as a potential energy source in most media reports of alternative energy. Several nations have committed billions of dollars so this must tell us something about the viability of He-3 projects as fuel. This subject certainly demands greater public attention and debate at a minimum. Let’s start that debate here on EDN with our engineering minds and experience. Please give your comments.