The Lemur 3 robot designed by NASA's Jet Propulsion Laboratory (JPL) can take advantage of the same attractive forces that geckos use to climb walls in order to perform tasks on the outside walls of the International Space Station (ISS).

NASA envisions a day when its lizard robots may climb the walls of the ISS using grippers inspired from nature. The Lemur 3's feet will simulate the super-adhesive feet of geckos.

Scientists at the NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California are developing an innovative "gecko gripper" system that will allow robots to perform maintenance tasks in outer space. They will inspect and repair the space station's exterior, as well as conduct a wide range of space activities in Earth orbit. Recently, the American space agency has also released a video describing the gecko space robot concept. 

According to Aaron Parness, JPL engineer, this kind of versatile robots will allow the space agency to have its satellites repaired on the orbit, serviced and even to have the space garbage collected and removed out of the way.

Gecko feet are naturally sticky but in a different way the tape is. The lizards rely on millions of tiny hair-like protrusions on their feet that become powerfully adhesive when are bent due to what scientists call van der Waals forces.

The van der Waals phenomenon is explained by the fact that the electrons orbiting a molecule's nucleus aren't evenly spaced. This makes even a neutral molecule to be charged into a positive side and a negative side. A 'stickiness" is generated because the positive side of one molecule attracts the negative side of neighboring molecules. This allows geckos to climb walls and walk across ceilings. By pushing their feet down and bending the tiny "hairs", the lizards can turn this adhesive force on, according to Parness.

The JPL team of engineers used the same principle inspired form nature for designing heir lizard robots. The gecko gripper robot Lemur 3 will work in pretty much the same way as the real gecko, according to Parness. The team working on the project has created a material studded with synthetic hairs smaller than a human hair. This material adheres when it is pushed against a surface.

According to JPL engineers, the latest generation of grippers developed by their team can support more than 150 Newtons of force. These numbers are big enough for the maintenance work tasks of the future space robots, being the equivalent of 35 lbs. (16 kilograms).

The advantage of this gripping system over the tape is that it doesn't lose its stickiness over time the way tape does. The researchers explained that this system should work well in all environments, including the extreme conditions in the outer space. The gripping system developed by JPL team will be able to withstand extreme pressures, temperatures, and radiations.