NASA Studying Tractor Beams - Not Science Fiction Any More

Nasa examines 'tractor beams' for sample gathering

US space agency Nasa has funded a study of "tractor beams" to gather samples for analysis in future missions.They are examining three laser-based approaches to do what has until now been the stuff of science fiction. Several tractor-beam ideas have been published in the scientific literature but none has yet been put to use.

Nasa scientist Paul Stysley says the approach could "enhance science goals and reduce mission risk. Though a mainstay in science fiction, and Star Trek in particular, laser-based trapping isn't fanciful or beyond current technological know-how," said Dr Stysley works at Nasa's Goddard Space Flight Center, whose group was awarded the research funding.

The team has identified three possible options to capture and gather up sample material either in future orbiting spacecraft or on planetary rovers. One is an adaptation of a well-known effect called "optical tweezers" in which objects can be trapped in the focus of one or two laser beams. However, this version of the approach would require an atmosphere in which to operate.

The other two methods rely on specially shaped laser beams - instead of a beam whose intensity peaks at its centre and tails off gradually, the team is investigating two alternatives: solenoid beams and Bessel beams. The intensity peaks within a solenoid beam are found in a spiral around the line of the beam itself, while a Bessel beam's intensity rises and falls in peaks and troughs at higher distances from the beam's line.

Solenoid beams have already proven their "tractor beam" abilities in laboratory tests but the pulling power of Bessel beams  remains to be proved experimentally. In all three cases, explained Dr Stysley, the effect is a small one - but it could in some instances outperform existing methods of sample gathering.

"In other words, they could continuously and remotely capture particles over a longer period of time, which would enhance science goals and reduce mission risk."