Is nuclear power the key to unlocking the solar system?

The prototype for a rocket engine from the 1970s could change the face of space travel in the future, writes Steven Cutts. But who gets there first will depend on who is prepared to take the biggest risk

Unlimited space travel could be one nuclear-powered rocket away (Nasa)

There is an idea that has persisted for most of the last 80 years and has the potential to transform interplanetary travel. It was born out of the Second World War and has progressed by fits and starts in every year that followed. It is an idea for a rocket so fast and so powerful that it could open up the entire solar system to human exploration.

In 1948, the technical journal of the British Interplanetary Society carried a proposal for a nuclear powered rocket motor. The first atomic weapons had just exploded on Japan and everything about the atom was in vogue. Although the proposal from 1948 was too technically complex to actually build, it did outline the principles upon which a nuclear rocket could be built. As the 1950s progressed, just about every science fiction writer in the business liked to write about an atomic future whenever they got near a typewriter and it would probably have come as a shock to most scientists to discover that in 2021, nuclear power is not the sole source of energy in the modern world. In the course of time, our enthusiasm for nuclear power became tempered. A variety of technical and political challenges but in the world of rocket propulsion, the dream of atomic power never really went away.

There are basically two schools of thought as to how nuclear power could be harnessed for space travel. One is based on the concept of nuclear electric power, where the energy to power an ion drive is derived from an on board nuclear reactor. The second is nuclear thermal where heat is generated in a fission nuclear reactor and used to energise the fuel.