The Nuclear Option - Lately there has been a revival of calls for nuclear space propulsion. NASA too is considering a new nuclear thermal rocket development program, and even an article in Forbes points out a nuclear thermal rocket as the better alternative to the Space Launch System (SLS) now in development.
Thus, the quickest way to finally actualize our 21st century space dreams may be to simply go nuclear. […] The benefits are obvious. Because a Nuclear Thermal Rocket (NTR) releases ten million times the energy of reactions in a chemical rocket, nuclear-powered rockets could cut current interplanetary transit times by half or better.
I’m going to have to level with you on this one: I’m a space enthusiast (to put it mildly) and fully agree the capabilities of an NTR rocket are massively beyond anything conventional rockets will ever achieve. However, I’m also an inhabitant of planet Earth, and have a pretty good understanding of the risks associated with every single launch we attempt. Even to me, the potential gain is not worth the potential price; we have only one Earth.
However, that does not mean we need to give up the promise of nuclear powered rocketry for interplanetary flight. In fact, this is one of the strongest arguments for establishing a permanent human base on the Moon. Use conventional rockets to get there first; we know it works and it’s only getting better. Then develop, test, and fly nuclear thermal rockets from the Moon to reach the rest of the solar system. Using water as a propellant (and topping off at strategic locations along the way) there is no planet, asteroid, or moon we cannot reach with this approach. And never endanger our home in the process.