Nextbigfuture had been tracking the project all of that time. In 2006, nextbigfuture had incorporated advanced wall climbing in a set of predictions of the future based on the anticipated success of the Z-man and several other approaches to climbing walls.
The project has taken longer than expected.
Whatever the scientists learned about gecko wall-climbing, whatever new approaches they took, the results didn't seem applicable to human use. "This program would have been over in two years if we could have done exactly what the gecko does," Main says. "But what the gecko does that humans can't do is flex between two contact points all the time. People can't get their hand on the wall and their foot on the wall, and put a lot of force into sliding them toward each other." Plus, there are all types of walls. What works on glass may not work on brick, which may not work on metal.
Draper Labs in Cambridge, Massachusetts had a minor breakthrough.
They had considered creating hand and foot paddles with a silicone "skin" made with nano-ridges, just like a gecko's. But it still wouldn't be strong enough to hold most people up on a wall. So they shifted their attention to another animal they'd been studying at the same time: spiders. In watching the insects climb brick, they discovered an ingenious array of fishhook spines, tightly assembled with the hooks facing downward. Those hooks grab into the brick face without slipping, as long as the spider's—or the climber's—body weight is suspended directly below them. Soon they developed hand paddles with tiny metal spines. And those paddles worked, allowing you to climb any wall, just as long as that wall was brick. This led researchers to also experiment with steel and iron.
The obvious material was magnets, and the two men created paddles that locked and unlocked from the wall by shifting a handle on the paddle up or down. Strap your legs in, and you could climb any surface, just as long as it was metal. The uses were immediately apparent. "There are a lot of steel structures like oil rigs that people needed safety and climbing equipment to manage," Main says. The magnetic paddles, which are depicted on the cover of this issue, have been licensed to a high-end military-supply company, Atlas Devices, and the technology is rumored to be already in use by special-operations forces to climb onto ships, tankers, and oil platforms.
For climbing glass and other smooth non-metallic surfaces, the team at Draper were inspired to combine the gecko skin and suction cups with leg power. Their new paddle consisted of synthetic gecko skin layered inside suction cups. To increase the efficiency of those suction cups, they attached foot stirrups to a series of pistons. When the foot stirrups are depressed, the pistons evacuate extra air inside the suction cups. This smashes the nano-ridges against the wall surface, activating the van der Waals forces. And when the suction is released by lifting the climber's weight off of the stirrup, the paddle can be easily moved elsewhere. Equally impressive is the cost: Carter and his team estimate that each pair will cost only $3,000 to $5,000.
Although it takes three types of paddles to conquer any surface instead of one, Main is confident that the technology will one day be combined into a single device. Like all military contractors, DARPA is cagey about if, where, and how the Z-Man has been deployed in the field.
SOURCES- DARPA, Popular Mechanics