Two days after it was launched from Cape Canaveral in Florida on May 20, the privately funded Lightsail1 spacecraft fell silent.

Mission controllers knew it was in a stable orbit 720km above Earth, but suspected a software glitch had stopped it from transmitting and receiving data.

They concluded the team would only be able to resume the $4m mission, and test the craft's 32 square metre ultra-thin Mylar sail, if the Lightsail1's systems were to reboot.

Unable to trigger this manually, the team instead hoped a fast-moving charged particle would strike the electronics components in the satellite in just the right way.

This happens to most small satellites during the first three weeks in orbit. Now it appears to have happened to Lightsail1.

"Our Lightsail spacecraft has rebooted itself, just as our engineers predicted," said Bill Nye, from the Planetary Society, the non-profit space advocacy group behind the mission.

"The team has coded a software patch ready to upload. After we are confident in the data packets regarding our orbit, we will make decisions about uploading the patch and deploying our sails."

Space sailing

The Lightsail1 mission is attempting to use sunlight to directly push a spacecraft through space using a sail.

The technology is based on the idea that the energy and momentum that exists in the photons in sunlight can pass onto an object.

By making the spacecraft very small in terms of mass, but with a very large sail, the researchers say it could propel spacecraft much more efficiently.

"They don't need any fuel. They don't need all the handling," says Nye. "You could go to the moon, you could go to Mars, you can catch up with comets and asteroids."

If the Lightsail team are able to update the software on board the spacecraft, their next challenge will be to test the deployment of the sail.

Earlier missions by the Japanese Space Agency and NASA ran into trouble with the deployment of the sails. The Planetary Society said they had overcome the technical problems they faced.

"This has been a rollercoaster for us down here on Earth," says Nye. "All the while our capable little spacecraft has been in orbit."