Scientists at the Jet Propulsion Laboratory, a NASA research center in Pasadena, California, are currently developing a powerful adhesive which, unlike duct tape, leaves no residue, and retains its stickiness even after multiple uses. Inspired by the remarkable technique employed by geckos to cling to walls and surfaces, the researchers have devised an incredibly innovative technology that could, one day, be used to remove orbital debris and defunct satellites from outer space.
Despite its widespread usage, the commonly-available duct tape has quite a few flaws. Ideally, it can be used only a couple of times before it completely loses its adhesion. Additionally, such tapes often leave behind a horrible, sticky residue that can be an absolute nightmare to get rid of. In their attempt to create a powerful, yet handy, adhesive, engineer Aaron Parness and his colleagues have turned to nature for inspiration. Belonging to the Gekkota infraorder, geckos are known for their unbelievably strong grip.
The bottom part of their feet feature millions of tiny bristles, which in turn provide a gripping strength of over 20 times their body weight. For a long time now, scientists have been fascinated by the amazing prowess of these tiny reptiles. According to a study, conducted last year, the lizard’s steely grip remains unabated even after its death, thus suggesting that the animal does not actively control its clinginess. Central to the phenomenon is the concept known as van der Waals force. NASA’s press release states:
A slight electrical field is created because electrons orbiting the nuclei of atoms are not evenly spaced, so there are positive and negative sides to a neutral molecule. The positively charged part of a molecule attracts the negatively charged part of its neighbor, resulting in ‘stickiness.’ Even in extreme temperature, pressure and radiation conditions, these forces persist.
The adhesive, created by Parness and his team, contains specially-designed synthetic hairs that are far thinner than an actual human hair. Applying force to make the bristles bend, in turn, causes the adhesive to stick to a given surface. What is more, these gecko-inspired grippers can be used to hold up to 35 pound (around 16 kg) of weight. Speaking about them, Parness said:
This is how the gecko does it, by weighting its feet. The grippers don’t leave any residue and don’t require a mating surface on the wall the way Velcro would.
So far, the team has conducted a number of tests, including a special microgravity flight test in which the material was used to adhere a 20 pound (nearly 10 kg) cube to a 250 pound (approx 100 kg) human. The researchers have also developed “astronaut anchors” that, they believe, could be utilized by astronauts working inside the International Space Station. Available in three different sizes, these hand-operated grippers could be used by astronauts to stick a variety of objects, such as clipboards, pictures and so on, inside the microgravity setting of a spaceship.
Furthermore, the scientists are currently working on LEMUR 3, a Limbed Excursion Mechanical Utility Robot capable of climbing in microgravity. Featuring a pair of gecko gripper-fitted feet, the robot could be used to locate and repair malfunctioning parts on the space station’s exterior. Talking about the possible applications of the technology, Parness said:
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.
Source : NASA