NASA’s Jet Propulsion Laboratory has already successfully used its “gecko grippers” to stick a 100 kilogram person to a wall and manipulate a 10 kilogram cube during tests conducted in micro-gravity. At Earth gravity, the latest generation grippers are able to hold up an object weighing up to 16 kg. The grippers, which are specially designed flat panels, are to be attached to a LEMUR 3 (Limbed Excursion Mechanical Utility Robot) prototype.
The gecko gripper technology, which is being developed simultaneously at various cutting-edge institutions around the world, including the defense agency’s DARPA and Stanford University, appears at first glance to be a work of magic. Unlike conventional sticky tape, there is no stickiness, and the gripper does not wear out with use – as NASA discovered after sticking a surface to foreign objects 30,000 times in a row with barely any loss of function. And in contrast to Velcro, there is no need for a second “mating” surface to make the object stick.
The principle behind the technology is van der Waals forces. Like the feet of spiders, the gecko gripper actually consists of thousands of microscopic hairs. Due to an even spacing of electrons around an atom, when together these form an electrical field. The stickiness is created by the positive particles being attracted to the negative. These forces only operate within nanometers, hence the need for tiny hairs. When millions of these work together, they can create a powerful cumulative force: a spider can lift 170 times its own weight while climbing along a smooth vertical force.
The stickiness is increased by simply pushing down harder, and making the hairs bend more.
“This is how the gecko does it, by weighting its feet,” said NASA engineer Aaron Parness.
The properties of the wonder-material, whose effectiveness is not hampered by temperature, radiation or other factors, would come in very handy for astronauts working at the International Space Station. NASA has already developed a series of patches that can be used to stick various objects like clipboards, and handheld devices to a wall in zero-gravity conditions.
Besides being used in developing more capable robots, NASA believes the technology could even revolutionize how spaceships interact with their outside environment.
“We might eventually grab satellites to repair them, service them, and we also could grab space garbage and try to clear it out of the way,” explained Parness.