As I understood it, the reaction mass for Orion comes from the chemical explosives used to implode the bomb. (The bomb design would be quite unusual, with several tons of explosives acting on a very small amount of plutonium).
There are better options if you want to go nuclear for propulsion. http://www.nasa.gov/pdf/718391main_Werka_2011_PhI_FFRE.pdf
It’s not an unreasonable amount of mass to get into LEO, and so very elegant as a drive.
As I understood it, the reaction mass for Orion comes from the chemical explosives used to implode the bomb. (The bomb design would be quite unusual, with several tons of explosives acting on a very small amount of plutonium).
There are better options if you want to go nuclear for propulsion. http://www.nasa.gov/pdf/718391main_Werka_2011_PhI_FFRE.pdf
It’s not an unreasonable amount of mass to get into LEO, and so very elegant as a drive.