Space junk is a growing threat. Today, about 500,000 pieces of man-made debris orbit planet Earth at a speed reaching 17,500 miles per hour. These debris can potentially damage satellites and even pose threat to the lives of astronauts aboard the International Space Station (ISS).

ESA astronaut Thomas Pesquet earlier raised concerns about the safety hazards that space junk poses to human lives. The ISS has already been maneuvered in the past to avoid potentially dangerous collision with space debris.

Cleaning Up Space Junk With Gecko-Inspired Adhesives

Cleaning up debris that litter in space, though, is not as easy as cleaning up trash on Earth. Suction cups, for instance, do not work in the space's vacuum. Traditional sticky substances such as tape can't withstand the extreme temperature swings, and magnets only work on magnetic objects.

Now, researchers came up with a new robotic gripper designed to collect and dispose of space debris. The gripper, which was featured in Science Robotics on June 28, used adhesives inspired by geckos.

Geckos can climb walls because of the microscopic flaps in their feet that create a Van der Waals force between the animal's feet and the surface they get full contact with. Van der Waals force refers to weak and tiny forces between atoms that are triggered by the movement of electrons at the atomic level.

Although the gripper is not as intricate as the feet of geckos, the adhesives, which have already been used in climbing robots and a system that give humans the ability to climb up certain surfaces in the past, works much the same way.

The gripper has a grid of adhesive squares that can stick to flat objects such as solar panels. It also has arms with thin adhesive straps that can grab curved objects such as a rocket body.

Robot Gripper Test In Microgravity

Last summer, the researchers took the gripper hand on a microgravity flight in NASA's Weightless Wonder aircraft and then used the object to grab and release objects, which include a cube, a beach ball, and cylinder that represented junks that litter in space such as satellites, pressure vessels, and rockets and fuel tanks.

In the experiments, the researchers found that the grippers successfully grasp and let go of the objects with just a gentle touch.

"The objects were really easy to knock away, so we are really happy that our adhesive gripper could grasp them with very little pressing force," said study researcher Hao Jiang, from the Cutkosky lab at Stanford University.

The grippers can handle objects up to 880 pounds in mass and those larger than it in volume.

"We present a robotic gripper that can gently grasp, manipulate, and release both flat and curved uncooperative objects as large as a meter in diameter while in microgravity," the researchers reported. "Tests in microgravity show that robotic grippers based on dry adhesion are a viable option for eliminating space debris in low Earth orbit and for enhancing missions in space."

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