For years we’ve seen high technology space operas tell us of “Tractor Beam” technology which allows a vessel to take a hold of an object in space and rather than repel it outward, actually pull it in toward the vessel. The technology is often seen as a sort of force field that can be emitted, but then instead of repelling objects outward actually pull them in. And now NASA has taken a few steps to actually make this high science fiction technology a reality. Displaying a level of expertise previously unseen outside of fiction, they say devices such as these may one day be used to take samples in space and even manipulate objects a bit closer to home.
But how does a tractor beam work? Up until now we’ve become very familiar with one type of laser – that is a laser where the very center is brighter and hotter while the outer edges of the beam are substantially less so. In experiments with high powered lasers, scientists and hobbyists have demonstrated the awesome destructive power of these devices which may not necessarily be quite as powerful as films in the past have promised, but which have a number of experimental and industrial uses. But this one specific type of laser is fairly limited in what it can do.
Solenoid Beams would involve two beams which would then act to create a force between them by changing the intensity as they spun around an object. And of course if that’s not quite futuristic enough there is also the Bessel Beam. Bessel beams are devices that fire a ring and then a point of light in such a way that it looks almost like a bullseye when a cross section is examined. True Bessel Beams, according to physicists, are impossible because they would require an infinite amount of energy. But the next best thing, which could easily fall under the same category, would be the Bessel-Gauss Beam. Such a device would be able to wrap around objects in space and then pull them inward without any external effects. Of course the power the beam exerts and the amount of energy used by such a device would be something of great interest to physicists partially because of the potential applications of such a device as a possible attachment to future Mars Rover missions.
In the past tractor beams were examined as a possible way for space capsules to move debris out of orbit. At the moment there is a considerable amount of space debris in Earth’s orbit, much of which could one day pose a hazard to satellites and even manned expeditions into orbit and beyond. If the beams could move this debris, some of which weighs over a ton, out of the way it may be the safest way of doing so – particularly if it could run essentially off of solar power drawn during the mission. Unfortunately, at least at the moment, the tractor beams are not considered powerful enough to move more than a small sample. Perhaps in the future, however, there will be more applications.