A revolutionary new type of solar powered engine will be at the centre of Europe's first ever mission to the Moon, project leaders have announced.
The Smart 1 craft employs solar power technology
They said the ion engines turn "science fiction into science fact" and will transform space travel by propelling craft at higher speeds over greater distances.
Once in orbit around the Earth's nearest neighbour the unmanned probe, called Smart 1, will use British technology to map the entire surface of the Moon for the first time.
It is hoped the mission will help form a better understanding of how the Moon was born and provide more information about its make-up.
On Monday morning the team behind the European Space Agency (Esa) probe said it would be launched on an Ariane 5 rocket on 4 September from Kourou in French Guiana.
But hours later it was announced that the date was being put back to help other teams using the rocket to launch their own satellites.
The ion engines have been used just once before, on a US space agency (Nasa) mission called Deep Space 1, and the Esa mission will provide an opportunity for further tests of the technology.
Uses electrical power provided by solar panels to accelerate a propellant to high velocity
Smart 1 uses the propellant xenon, a colourless gas
Electrons trapped inside a chamber by a magnetic field collide with xenon gas creating xenon ions and more electrons
The resulting ion beam pushes the space craft forward
The thrust produced is equivalent to the pressure exerted by a sheet of paper held in the palm of a hand
Over long periods, it can make a spacecraft travel significantly faster
Solar panels provide power to the ion engine, which are believed to be capable of accelerating spacecraft to speeds greater than those possible with rocket engines.
Ion engines are also 10 times more efficient than rockets and could cut the time needed for interplanetary journeys.
Sir Patrick Moore said: "It is a pioneering method of propulsion, ion propulsion is a means of
space travel for the future. This is a pioneering vessel, smart in every way."
After a leisurely 15 month journey to the Moon, the washing machine sized craft will be used to produce an X-ray map of the Moon in an attempt to discover precisely how it was made.
The craft will make an x-ray map of the moon
The technology to do that has been designed by scientists from the Universities of London, Sheffield and Manchester.
One idea behind the Moon's formation is that a Mars-sized object smashed into the juvenile Earth, flinging up debris which later merged to form the Moon.
If this actually happened, the Moon should contain less iron than the Earth, compared to lighter elements such as magnesium and aluminium.
By measuring the amounts of these chemical elements comprehensively for the first time, Smart 1 should provide the answer.
Professor Manuel Grande, a leading British scientist on the project, described the mission as "a lot of firsts rolled into one mission".
"This is the first European mission to the Moon, this is the first smaller, faster mission and this is the first solar-powered spacecraft," said the professor, of the Rutherford Appleton Laboratory in Oxfordshire.
The lunar probe had been due to leave Earth in March but its take-off was postponed following a failed rocket launch last December.
The incident led to a shake-up of the Ariane 5 rocket launcher programme, and several Esa space missions were put on hold.