It’s an idea that has been plagued by misfortune. Now, proponents of technology that seeks to propel spacecraft using the pressure exerted by photons from the sun on thin “solar sails” look set for another chance to get their idea off the ground.
Missions by the US non-profit Planetary Society to test solar sail technology failed in 2001 and 2005, because the rockets needed to get them into space malfunctioned. Now they look set for a comeback as early as 29 July, when a tiny NASA spacecraft called NanoSail-D is scheduled to go into Earth orbit.
The aim is to demonstrate the feasibility of deploying sails in orbit. The spacecraft will unfurl four 3-metre-wide sails made of plastic film coated with aluminium. In addition to feeling pressure from sunlight, it is hoped that the sails will experience a slight drag from Earth’s outer atmosphere. Similar sails could one day be used to bring normal satellites back to Earth after their missions, reducing orbital clutter.