NASA is taking a page out of the book of science fiction, announcing plans to develop a real-world tractor beam.
NASA announced on Monday that it had awarded three scientists $100,000 to study the use of light beams to gather atmospheric or planetary particles, like molecules, cells and viruses, for analysis.
“Though a mainstay in science fiction, and Star Trek in particular, laser-based trapping isn’t fanciful or beyond current technological know-how,” said NASA officials.
The team has identified three different approaches for transporting particles, as well as single molecules, viruses, ribonucleic acid, and fully functioning cells, using the power of light. NASA announced the awards Monday, each one of which totals $100,000.
NASA said the tractor beams would allow robotic rovers and orbiters the ability to gather samples a way to collect passing particles, including space particles and space dust.
One experimental approach the team plans to study — the optical vortex or “optical tweezers” method — involves the use of two counter-propagating beams of light. The resulting ring-like 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.
Another technique employs optical solenoid beams — those whose intensity peaks spiral around the axis of propagation. Testing has shown that the approach can trap and exert a force that drives particles 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.