In my previous article on the history of nuclear pulse propulsion, I outlined three research programs in nuclear propulsion systems for space travel.  The first of these, Project Orion, was investigated in the 1950s and 1960s as a very serious and practical option for space travel.  Its only limiting factor was the signing of the International Test Ban Treaty in 1963 that barred the detonation of nuclear weapons in space.

In this first of a series of articles on nuclear propulsion for space travel, allow me to enlighten each of you about the fascinating history of this technology. This post will cover three early projects, with posts to follow that will explore other technologies along with an assessment of future prospects.