Drawing inspiration from the super-sticky feet of geckos, NASA researchers are designing a new robot capable of climbing up the walls of the International Space Station to inspect and repair the exterior of the orbiting laboratory, the US space agency announced last week.
According to Space.com, scientists at NASA’s Jet Propulsion Laboratory facility in Pasadena, California are working on a “gecko gripper” system that would work similar to the way the millions of tiny hairlike structures on the bottom of the lizards’ feet help them become excellent climbers thanks to a phenomenon known as van der Waals forces.
Since the electrons orbiting the nuclei of atoms are not evenly spaced, a slight electrical field is created, meaning that neutral molecules have both a positive and a negative side. The positively charged part attract the negative side of nearby molecules, and vice versa, which in turn causes “stickiness” that allows geckos to climb walls and walk across ceilings.
JPL engineer Aaron Parness and colleagues are creating synthetic fibers, thinner than a human hair, that take advantage of these forces. Similar to how geckos “switch on” their stickiness by pushing their feet down to bend the hairlike structures on their feet, the robot’s fibers will have a force applied to them to make them bend and become adhesive.
Stick surface usable for repair robots, astronaut anchors
The gecko-inspired robot is called the Limbed Excursion Mechanical Utility Robot (Lemur), and Parness said that the grippers it will use “don’t leave any residue and don’t require a mating surface on the wall the way Velcro would.” Currently, they can support more than 150 Newtons of force, or the equivalent of 35 pounds, according to NASA.
Last year, the agency conducted a microgravity flight test in which the technology was used to grapple a 20-pound cube and a 250-pound person, and the gecko-inspired material underwent a separate test involving turning the stickiness on and off for more than 30,000 cycles back when Parness was a graduate student at Stanford University. It remained strong throughout the tests.
The JPL team has been testing Lemur 3 and its gecko-gripper feet in simulated microgravity, and they believe that it could be used to conduct inspections and perform repairs on the outside of the ISS. Parness said that the technology could ultimately be used to “grab satellites to repair them, service them, and we also could grab space garbage and try to clear it out of the way.”
In addition, the technology has been used to create three different sizes of “astronaut anchors,” hand-operated adhesive units that would make it easier for crewmembers to attach clipboards, photos, or other items to the interior walls of the station. Astronauts would attach the object to a gripper’s mounting post by pushing together the two components of the gripper, NASA noted. This part of the project is a collaboration between JPL and the Johnson Space Center.
(Image credit: NASA/JPL-Caltech)
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