Spacecraft sailing on sunbeams begins test flight

Craft financed by crowd-funding piggy-backs on the launch of an Atlas 5 rocket

A tiny spacecraft designed to sail on sunbeams has been launched in a test flight that could transform long-distance space exploration.

The probe, called LightSail, is equipped with a huge silver sail that will unfurl in the coming weeks and use the momentum of sunlight to propel it smoothly through space.