Cosmos 1, the world's first space craft propelled by a solar sail, has lost contact with its base station.

The ship was launched on schedule from a submarine using a converted Russian ICBM and should have signalled to three base stations on Earth and deployed its eight solar sails, each a quarter of the thickness of a plastic bag.

However, only a few faint signals were received after take off and those have now stopped.

"That the weak signals were recorded at the expected times of spacecraft passes over the ground stations is encouraging, but in no way are they conclusive enough for us to be sure that they came from Cosmos 1 working in orbit," said project director Louis Friedman.

The Russian Space Agency indicated that its Volna rocket may have had a problem during its first or second stage firing.

The mission was funded by the Planetary Society, a group set up by US astronomer Carl Sagan to encourage space flight.