British aircraft engine maker Rolls-Royce has formed an unlikely alliance with the UK Space Agency to develop nuclear-powered spacecraft engines. The collaboration will see the two organisations working together to explore the potential of nuclear power as a source of energy for future expeditions into deep space. If successful, a nuclear spacecraft could cut the journey time to Mars to just three to four months - roughly half the time possible using current chemical engines. What's more, the reduced journey times would mean astronauts on board the spacecraft are exposed to less radiation during the flight, making future trips to Mars or other planets safer.