SPACE LIZARDS

NASA looked to gecko feet for its latest space innovation

By studying what makes geckos’ feet sticky, NASA scientists have created a device that will adhere to almost anything.

The “gecko gripper” uses minuscule silicon wedges to latch onto a wide range of slippery surfaces, like solar panels and plastics. The grippers can work with heavy objects, easily maneuvering, say, an adult male, or a 278 kg (613 lb) robot. NASA hopes to use gecko grippers in place of traditional adhesives like Velcro, which are trickier to use in space and can leave behind residue. Since they’re made of silicon, the grippers can also withstand extreme pressure, temperature, and radiation conditions.

Gecko grippers adhere to testing objects using the same scientific forces as a gecko climbing up the glass in its tank. A single gecko foot contains about half a million tiny hairs called setae. The ends of these hairs may be small, but together they create a powerful connection between the foot and the surface. That connection takes advantage of Van der Waals forces, which occur when the electrons inside an atom or molecule aren’t evenly spaced, creating a negative pole and a positive pole. This causes other molecules or atoms nearby to become polarized, creating a weak electrical field that temporarily allows the gecko to stick. While gecko grippers use silicon wedges instead of setae, they too experience the sticky powers of Van der Waals forces.

Gecko grips could be used for a variety of purposes, but scientists are especially interested in their ability to clean up floating debris in space. Chunks of space trash can endanger satellites and space stations, so removing them is key to preventing future damage. Velcro is bad for collecting debris because it requires two points of connection: a strip of Velcro on the trash-collecting device, and a strip on the debris itself. Gecko grippers could be a viable solution.

Correction: This story has been edited to capitalize Velcro, as it is a registered mark of Velcro Companies.

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