11 ms·

Launching from lunar orbit would obviate EMP and terrestrial radiation concerns. But those are the least of the concerns.

• ianburrell 4y ago
  The problem with that is Orion is that it is heavy. It only makes sense when launching the whole thing from the ground. Orion has been proposed for interplanetary propulsion since it is pretty efficient. But would need to be convertible from ground-launch to space propulsion. Nuclear rockets are pretty good and safer to launch. The other problem is that nuclear weapons are expensive. Something like Davy Crockett is 2kg of plutonium, and mid-sized Orion would use 800 to get to orbit. Plutonium is $4000/g which means $6.4 billion to launch Orion. Orion that puts 1600t in orbit. Or 10 Starships which is less as disposable rockets and way less if reuasable.
  • philipkglass 4y ago
    In 1965 the Atomic Energy Commission put the cost of plutonium 239 at $10/gram, which by simple consumer price indexing (only a rough guide, admittedly) would make it $96/gram today. See Table I in this publication "Values In Spent Fuel From Power Reactors": https://www.osti.gov/servlets/purl/4618921 https://www.osti.gov/servlets/purl/4618921 At $96 per gram instead of $4000, that's a much more attractive $154 million to put 1600 tons in orbit. Uranium enrichment costs have fallen greatly since the 1960s as centrifuges have replaced gaseous diffusion, so uranium-fueled units would probably cost less (despite the greater mass of uranium required). I'd say that the main modern problems of a terrestrially launched Orion are treaty violations and giving a plausible cover for nations to again pursue developing "peaceful" nuclear explosives.