Tractor Beams On NASA's Wish List
By Ron Grunsby
A team of scientists at NASA's Goddard Space Flight Center in Greenbelt, MD, has been awarded $100,000 by the NASA Office of the Chief Technologist to study the feasibility of developing tractor beams — the ability to trap and move objects using laser light.
These tractor beams will not be moving spaceships or meteors. The goal is to remotely collect planetary or atmospheric particles and bring them to a robotic rover or orbiting spacecraft for analysis. This technology could facilitate the collection of these particles over a longer period of time and over a longer range than current methods, such as using aerogel or drilling and scooping. Tractor beam technology could also prove to be less costly.
NASA’s original ambition was to use a tractor beam for cleaning up orbital debris, “but to pull something that huge would be almost impossible — at least now,” said principal investigator Paul Stysley. “That's when it bubbled up that perhaps we could use the same approach for sample collection."
Three approaches will be investigated. First, the optical vortex, or "optical tweezers," method involves trapping objects in the focus of one or two laser beams. An atmosphere must be present for this to work.
In the optical solenoid beam approach — the second technique that will be explored — the particles are pulled back along the entire beam of light. This technique relies on electromagnetic effects and can work in a vacuum, making it relevant in the study of materials on a moon without an atmosphere, for example.
Finally, the Bessel beam technique has not been proven experimentally. When shined against a wall, regular laser beams appear as a point, but with Bessel beams, rings of light encircle the dot. It is theorized that the Bessel beam could induce electric and magnetic fields in the way of an object, and the light scattered forward by these fields could pull the object backward against the beam’s movement.
Once an approach is chosen, the team will look to formulate a system and compete for more funding to advance the project.