Nasa funds research into 'tractor beams' - Telegraph.co.uk

The first is a variation on the "optical tweezers" method, where two crossed lasers use their heat to tow a sample in. It depends on a planet having an atmosphere and so may not be suitable for more distant explorations.

A second uses solenoid beams, intense lasers that create an electromagnetic effect to drag in an object. Unlike the optical tweezers, he solenoid beams work in a space vacuum.

The final technique has never been demonstrated in a lab but is based on a Bessel beam, a laser that creates ripples – like a stone thrown in a pond – which could coax a sample in.

"We're at the starting gate on this," said laser scientist Barry Coyle. "This is a new application that no one has claimed yet."