Why thank you-- nuclear rocketry.
If you mean something like NERVA, it’s a fine idea once you’re already in space but not particularly useful to get there from here.
If you mean something like Orion nuclear pulse propulsion, that’ll work great for getting into space, but you’ll have a tiny PR problem with setting off a thousand nuclear warheads in the atmosphere to do it.
You’re still shooting something hot out the back end of a pointy thing...
Nuclear. My favorite is project orion. BOOM BOOM BOOM BOOM etc