PORTLAND, Ore. Luke Skywalker's space racer hovered unpowered above the ground in the seminal Star Wars movie, but scientists have searched in vain for a real-world technology that realizes the same dream. Now, Cornell University researchers propose that superconductors paired with permanent magnets could fit the bill.
Superconductor technologies designed at Cornell aim to hold space-station modules and satellites in place without tethers or retrorockets by magnetically "pinning" them in place. Using unpowered superconductors and fixed permanent magnets, the Cornell researchers claim a new-age solution to longstanding stability and control problems in space vehicles.
Cornell hopes to prove the concept of magnetic pinning using unpowered superconductors for NASA spacecraft that must assemble themselves in orbit without the help of astronauts.. Within six months, the researchers plan to have a working test bed in place to verify that unpowered superconducting architectures can stabilize and control spacecraft.
"We believe that magnetic pinning with superconductors will enable much more stable space platforms to be constructed and held together without physical connections," said Cornell University professor Mason Peck. "Modules that are magnetically pinned will also have a built-in bumper that prevents them from accidentally bumping into each other, potentially preventing the kind of damage that is hard to repair in space."
Magnetic pinning works by placing two space modules—one with an unpowered, but supercooled, superconducting coil and the other with an ordinary permanent magnet—near each other. The permanent magnet induces a current in the superconductor that is persistent and exactly opposite to the field of the magnet. In essence, one essentially "grips" the other with an invisible magnetic glove.
"When you bring a permanent magnet near a superconductor, it induces a current that stays there and exactly opposes the magnet's own field--these are tiny current loops at the quantum level," said Peck. "This in effect links the two objects with equal, opposing magnetic fields that keep them hovering next to each other indefinitely without supplying any external power. Even when external forces perturb them, they will maintain both their rotational and translational position."