Instapundit found some reportage on the fission rocket. They want to use liquid hydrogen for propellant. Fission here is "enriched" uranium, so mostly U-238 with enough U-235 to power the engine. Hydrogen is reactive so the uranium is enriched not quite to 20%.
For power, why not "thorium" meaning U-233. Fewer neutrons and it's lighter. Every Gram Counts.
For propellant, why hydrogen. I get it for fusion. I get it for BELTALOWDA out beyond the snow line. But why for fission from Earth? Sorry to do the Hilder thing from The Martian Way but... he was / will be right, inasmuch as hydrogen is not busting out of nowhere, down here. Venus has an absolute hydrogen shortage. If chemical reactions are a worry why not use some elemental kin to hydrogen with under 2700 K boiling-point, that we don't need here. UPDATE 8/27/21: Yes, chemical reactions were a worry - such a worry, we don't even care about cost. As to cost: Ammonia.
Say: sodium. Almost 23 times the atomic mass. We store it solid and heat it to liquid state. Don't even need to pressurise this. If cost is a worry then how about sulfur, at 16 masses? Venus got that to spare. It's cheaper by mass than hydrogen even here.
Io also has sulfur. As with our Moon, chemical reagents will push cargo into escape velocity; the trick here is escaping Jupiter. Viewed from the inner planets, our transfer Hohmann will be from Io's orbit right to Callisto's. I haven't the maths for that delta-V but I'm expecting well over 10 km/s total. I'm thinking that this rocket hasn't the thrust to move around the Jovian system in a timely fashion - and given Jupiter's radiation, you do want out of here a.s.a.p.
No comments:
Post a Comment