It came in the shape of a 17th-century clergyman who drew up plans for a spaceship powered by wings, springs and gunpowder, a leading science historian will reveal this week. According to Professor Allan Chapman of Oxford University, it was the first serious attempt at a manned flight to the Moon.

The man behind the lunar mission was Dr John Wilkins, scientist, theologian and brother-in-law of Oliver Cromwell. In 1640, as a young man of 26, Dr Wilkins wrote a detailed description of the machinery needed to communicate and even trade with beings from another world.

"It was the first serious suggestion of space flight based on the best documentary evidence available to them at the time," said Professor Chapman, who will present his findings tomorrow night at a public lecture at Gresham College, London.

Although earlier philosophers and poets had written about visiting the Moon, the writings of Dr Wilkins were in an altogether different league, Professor Chapman believes. Wilkins lived inwhat he describes as the "honeymoon period" of scientific discovery, between the astronomical revelations of Galileo and Copernicus, who showed a universe with other, possibly habitable worlds, and the later realisation that much of space was a vacuum and therefore impassable.

According to Dr Wilkins, the gravitational and magnetic pull of the Earth extended for only 20 miles into the sky. If it were possible to get airborne and pass beyond this point, it would be easy to continue on a journey to the Moon. Inspired by the discovery of other continents and the great sea voyages of explorers such as Francis Drake and Walter Raleigh, Wilkins conceived an equally ambitious plan to explore space.

"Partly the argument was religious. As well as being a scientist, Wilkins was a theologian, and the argument was that if God had made worlds then it's within divine providence to put beings on them," Professor Chapman said.

Dr Wilkins drew up plans for what he called a flying chariot powered by clockwork and springs, a set of flapping wings coated with feathers and a few gunpowder boosters to help send it on its way.

"Of course his approach did not work because he based it on the premise that the Earth's pull only went up 20 miles and if you crossed that 20 miles, you could float after that," he said.

By the 1660s, the idea began to fall apart with the work of Robert Boyle and Robert Hooke, who demonstrated the nature of the vacuum that would stretch between the Earth and the Moon.

"He also came to realise that magnetism and gravity are not the same thing. So there was not going to be what Wilkins described as a 'sphere of magnetic virtue' 20 miles around the Earth which once you break through that will allow you to float out into space," Professor Chapman said.

Wilkins also had some other peculiar ideas of space travel that would make it easy to travel the quarter of a million miles to the Moon. He believed, for instance, that in space, men would not have much need for food.

"In space we wouldn't need to eat because the reason why we need to eat on Earth is that the pull of gravity pulls food through our bodies and constantly empties our stomachs," Professor Chapman explained.