A privately funded space project to demonstrate an innovative solar sail passed with flying colours despite a series of near-fatal technical issues, programme managers said.

The five kilogramme LightSail spacecraft, tucked inside a small box, hitched a ride into orbit aboard an Atlas 5 rocket carrying the US Air Force's X-37B robot space plane on May 20.

Funded by members of The Planetary Society, a California-based space advocacy organisation, LightSail was intended to demonstrate how a tiny motor could unfurl four thin Mylar films into an area as big as a living room.

A follow-on mission planned for late next year would put a similar satellite into a higher orbit so that it could practice a space propulsion technique known as "solar sailing." The idea is to make use of the pressure of photons from the sun against a film to generate forward motion.

LightSail overcame communications problems, software glitches and battery issues before finally unfurling its quartet of sails last Sunday. Confirmation of the deployment came via a spacecraft self-portrait.

Project managers are mulling other tests to put the spacecraft through before it succumbs to Earth's gravity and is pulled back into the atmosphere sometime this weekend.