Engineers at Nasa have also been drawing up plans to use nuclear thermal propulsion in a mission to Mars in 2033.

According to the space agency's design, uranium-235 nuclear reactions are used to heat liquid hydrogen inside a reactor, turning it into ionized hydrogen gas, or plasma.

This plasma is then channeled through a rocket nozzle to generate thrust.

The proposed Copernicus spacecraft would use nuclear thermal propulsion to carry astronauts to Mars

A schematic of the nuclear thermal rocket shows how liquid hydrogen propellant would heated by the reactor

Dr Stanely Borowski, an engineer at Nasa's John Glenn Research Centre, last year outlined how this could then be used to propel a space with its crew through space in a official Nasa paper.

He said the spacecraft, called Copernicus, would consist of separate cargo and crewed transfer vehicles, each powered by a nuclear thermal propuslion stage.

These would be constructed from a 'core' that use three engines each capable of producing thrust of around 25,000 lbs of force.

He estimates that these vehicles could make the 40 million mile trip to Mars within 100 days.

It took the Mars Science Laboratory spacecraft carrying Nasa's Curiosity Rover to Mars 253 days to reach the red planet.

Writing in his paper, Dr Borowski said: 'The analysis presented here indicates transit time reductions as much as 50 per cent are possible.'

Nasa first began researching nuclear thermal rockets as part of its Nuclear Engine for Rocket Vehicle Application (NERVA) programme in 1959.