NASA Funds ‘Tractor Beam’ Study
GREENBELT, Md., Nov. 2, 2011 — Though a mainstay in science fiction, tractor beams may no longer be limited to the likes of our imaginations. Thanks to recent funding awarded to NASA’s Goddard Space Flight Center, three experimental methods for corralling particles and transporting them via laser light to an instrument are now being studied.
NASA's Office of the Chief Technologist is funding a $100,000 study to investigate three different approaches for transporting particles, molecules, viruses and cells by the power of light. (Image: NASA Goddard Space Flight Center, Conceptual Image Lab)
The NASA Office of the Chief Technologist (OCT) has awarded principal investigator Paul Stysley and team members Demetrios Poulios and Barry Coyle at Goddard Space Flight Center $100,000 to study three different approaches for transporting particles as well as single molecules, viruses, ribonucleic acid and fully functioning cells by using the power of light.
“The original thought was that we could use tractor beams for cleaning up orbital debris,” Stysley said. “But to pull something that huge would be almost impossible — at least now. That's when it bubbled up that perhaps we could use the same approach for sample collection.”
NASA Goddard laser experts (from left to right) Barry Coyle, Paul Stysley and Demetrios Poulios have won NASA funding to study advanced technologies for collecting extraterrestrial particle samples. (Image: NASA Goddard Space Flight Center, Debora McCallum)
With the Phase 1 funding from OCT's recently reestablished NASA Innovative Advanced Concepts (NIAC) program, designed to spur the development of revolutionary space technologies, the team will study the state of the technology to determine which of the three techniques would apply best to sample collection.
The three approaches
One experimental approach the team plans to study — the optical vortex or “optical tweezers” method — involves the use of two counterpropagating beams of light. The resulting ringlike geometry confines particles to the dark core of the overlapping beams. By alternately strengthening or weakening the intensity of one of the light beams — in effect heating the air around the trapped particle — researchers have shown in laboratory testing that they can move the particle along the ring's center. This technique, however, requires the presence of an atmosphere.
Goddard technologists are studying different techniques for corralling particles and transporting them via laser light to instruments on rovers and orbiting spacecraft. (Image: Dr. Paul Stysley)
Another technique employs optical solenoid beams — those whose intensity peaks spiral around the axis of propagation. Testing has shown that the approach can trap particles and exert a force that drives them in the opposite direction of the light-beam source. In other words, the particulate matter is pulled back along the entire beam of light. Unlike the optical vortex method, this technique relies solely on electromagnetic effects and could operate in a space vacuum, making it ideal for studying the composition of materials on one of the airless planetary moons, for example.
The third technique exists only on paper and has never been demonstrated in the laboratory, Poulios said. It involves the use of a Bessel beam. Normal laser beams when shined against a wall appear as a small point. With Bessel beams, however, rings of light surround the central dot. In other words, when seen straight on, the Bessel beam looks like the ripples surrounding a pebble dropped in a pond. According to theory, the laser beam could induce electric and magnetic fields in the path of an object. The spray of light scattered forward by these fields could pull the object backward against the movement of the beam itself.
“We want to make sure we thoroughly understand these methods. We have hope that one of these will work for our purposes,” Coyle said. “Once we select a technique, we will be in position to then formulate a possible system. We're at the starting gate on this: This is a new application that no one has claimed yet.”
For more information, visit: www.nasa.gov/goddard
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