NASA Technical Reports #2

Helium-3 Mining Aerostats in the Atmospheres of the Outer Planets

Daedalus assumed He3 sourced from Jupiter, but the other three gas giants would be better due to Jupiter’s massive gravity-well. Uranus seems the best choice – as I jokingly put it, He3 from the Gas Mines of Uranus – for accessing this very attractive fusion fuel. However the energy requirements reported in this NASA paper are quite at odds with the figures derived by Bob Parkinson for Daedalus, a discrepancy I can’t yet explain. There’s more helium and helium-3 than what Parkinson assumed, so the task is easier, but the energy levels are an order of magnitude higher. This means extracting sufficient He3 is a mammoth task and a significant fraction of any interstellar effort.

For that reason I advocate developing deuterium propulsion. Pure deuterium fusion puts out about ~1/3 its energy as neutrons (versus 4/5 for D-T fusion) making it challenging to operate at high power-levels. However the prospect of ultra-dense deuterium, 1 million times denser than liquid deuterium, makes this potentially a very good choice indeed. Quite possibly ultra-dense deuterium forms naturally inside super-Jovian planets, which makes for the intriguing possibility of planetary collisions causing deuterium fusion explosions, with all sorts of exotic isotopic anomalies arising… much like what’s seen in our Solar system.