Running straight up a wall like something out of the Matrix is still in the realm of sci-fi, but DARPA (Defense Advanced Research Projects Agency) announced that its Z-Man program had a reached a new milestone when a man climbed up a 25-foot glass wall without the use of ropes using technology based on gecko toe pads.
Gecko toes are great example of evolution engineering ingenious solutions to practical problems. The toe pad is made up of tiny stalk called setae which in turn fan out into hundreds of spatula which are just 200 nanometers wide. The result of packing all this surface area into a tiny volume is a combination of frictional adhesion and intermolecular van der Waals forces strong enough for a gecko to hang from a single toe but that can be attached and detached with ease.
Since their toes don’t rely on surface chemistry (unlike glue or adhesive tape), geckos can run up a sheer glass wall as easily as the side of a boulder.
A sheet of Geckskin can hold a 660-pound static load
The Z-man project wants to simulate and scale that ability for soldiers to use during operations with a material called Geckskin (plenty of DARPA projects end up having civilian non-military applications: the internet’s first name was ARPANET). Researchers had already proven that Geckskin could support incredible sheer loads (a 16 inch sheet was used to hold up 660 pounds), but this is the first time that it was successfully used as a climbing system. Climbing with the equipment in the Z-man project isn’t particularly fast, at least not in this iteration, because you have to manually detach/reattach one Geckskin anchor while the other supports your weight (n.b. the climber in the image is still hooked up to a rope for safety reasons).
Z-man lets soldiers climb in parallel
Even if the Z-man project innovates on this design so that using the equipment is less tedious, it already has a significant advantage – people can scale a wall in parallel instead of in sequence. Normally the first soldier scaling a wall has to take all the risk, arriving on top by themselves and waiting for everyone else to follow him up. With Geckskin soldiers can climb and arrive at the same time, a big difference if there is trouble waiting for them. Geckskin also makes climbing easier in an urban environment when climbing up the side of a wall with normal rock climbing equipment isn’t realistic.