intellitech sends this quote from a NASA news release:
"Tractor beams — the ability to trap and move objects using light — are the stuff of science fiction, but a team of NASA scientists has won funding to study the concept for remotely capturing planetary or atmospheric particles and delivering them to a robotic rover or orbiting spacecraft for analysis."
Reader Bob the Super Hamste adds, "The article along with the BBC's coverage
discuss briefly three methods of how this can be done with lasers. The first method called 'optical tweezers,' in which a molecule is trapped where two beams cross
(PDF). However, it requires an atmosphere to work. The second method using solenoid beams has already worked in the laboratory
(PDF). The third method using Bessel beams
has yet to be experimentally proven."