Time for the second review in our week of Lost in Science Fiction, aka science in the movies.
This is one of those annoying movies with a twist, so I can’t say too much about what happens (although recent research has shown that spoilers can actually make stories better). But suffice to say it’s about a guy (Sam Rockwell) living on the Moon, with only a computerised Kevin Spacey for company.
He’s there to mine for helium-3, an isotope that has one less neutron than the more common helium-4 (which has two neutrons and two protons in its nucleus. Helium-3 still has the two protons and hence the same chemical properties, but lacking a second neutron it has a lower atomic weight).
Helium-3 has been suggested as a possible fuel for nuclear fusion: two helium-3 nuclei can combine to create one helium-4 nucleus and two protons, as well as a whole lot of energy. It’s also used in neutron detectors and to achieve extremely low temperatures in cryogenics.
The trouble is that helium-3 is extremely rare, about 1/10,000th the abundance of helium-4, or around 7.2 parts per trillion in the atmosphere. In fact, most of the helium-3 used on Earth is manufactured.
However, the situation on the Moon is more promising. The lunar regolith, or dirt, may contain up to 50 parts per billion on some parts of the surface. As a result, mining the Moon for helium-3 is a potentially lucrative industry, and it seems to be one of the main reasons the various spacefaring nations are once more interested in lunar exploration.
So, for an interesting depiction of this potential future industry – with a fascinating psychological twist – check out the movie Moon.
Or if you want to try helium-3 mining for yourself, have a go at the Helium-3 Space Game on YourDiscovery.com.