Orion

We live in a world of 'what if?'
The book takes place in world created The Colonisation of Mars in which the Americans sent a mission to Mars in the 1970s by a nuclear-pulse powered spaceship - Orion. While this was actually planned in 'our' world this did not happen for a number of reasons. Number one was probably the creation of NASA and their involvement in the Race to the Moon. Also, President Kennedy was evidently opposed to it and the Nuclear Test Ban Treaty blocked it.

The world of this book saw nuclear bombs used to end World War II in Europe too and become an everyday fact of life to build canals, to dig ditches, for mining and to resolve border disputes.