The Slide Rule

Prior to the electronic calculator, this was one of the most important tools available to engineers and mathematicians. Whether linear or circular, they can be used to find roots and powers, take exponentials and logarithms, determine trigonometric functions or simply perform the four most basic mathematical operations. Within the space program itself, they were particularly useful during its infancy, being taken on five Apollo missions. In addition, no device can be accurately created without calculating its dimensions, and the slide rule was an integral part of both the meticulous design of Concorde and the early progeny of the space program. It was also an essential tool for the bombardiers and navigators involved in World War II, where quick calculations were imperative. Given this auspicious history, the slide rule can be seen to have played a significant part in the development of modern life.

If ever power were to fail in a spacecraft, batteries included, then the slide rule would be the only means of quickly calculating rocket burn-times and trajectories to get the crew safely back to Earth. It may have been superseded by its counterpart of the electronic age, but this does not detract from its mechanical ingenuity and simplicity. It may have been one small step in the development of current technologies, but its value has lasted (and for some, continues to last) for one giant leap of time.

Submitted by: Marc Maidment