This is the first time I've come across physics-trail. You might be interested in these posts about nuclear rocket motors:
https://steemit.com/mars/@professorbromide/nasa-announces-contract-to-develop-nuclear-rocket-motor
https://steemit.com/mars/@professorbromide/nasa-going-to-mars-in-a-nuclear-powered-rocket
I didn't know that there was a significant of interest in physics on the chain so I didn't put the physics tag in them.
RE: Physics-Trail Magazine N.3 - Best Recent Physics Content on Steemit