Published June 28, 2012
Soldiers will soon be able to scale any vertical surface without slipping, just like Spider-Man -- with help from cutting-edge technology rather than a spider bite.
Without the use of ropes, ladders, or glue, the tech makes it possible to climb a wall carrying a full combat load. News reports earlier this month touted one such technology from Utah State University, which relies on suction cups to ascend sheer walls.
Vacuums are just one approach, however.
Several other programs seek to enable Spidey powers in warfighters, many inspired by the humble gecko: The tiny, 5-ounce lizard can scale a wall carrying 9 pounds of weight -- a whopping 18 times its body weight.
If this super power could be extracted from nature, mimicked and applied to humans, Peter Parker's secret powers become very real.
People assume geckos achieve their climbing capabilities through suction cups on their feet or by secreting a sticky goo. Instead the stick is achieved by millions of tiny hairs on the soles of the gecko’s feet. These hairs keep its toes in contact with the surface, creating molecular forces of attraction.
Each hair has a mushroom-shaped cap less than one-thousandth of a millimeter across at the tip; the attractive force for a single hair may be miniscule, but multiply it by the millions of hairs found on each foot and you get solid footing, straight up a wall.
Geckos simply peel their feet away from the surface to release a foot.
BAE System’s Advanced Technology Center has one of the top programs and it closely mimics the gecko. The center has succeeded in creating a material that is a sort of artificial version of the bottom of the gecko’s foot.
Their material has polymer layers comprised of thousands of microscopic stalks with splayed tips like the gecko hairs.
When the material’s ability to stick to glass was tested, the result was a pull-off force of 3,000 kg per square meter.
Put BAE’s material on the palms of human hands and it’s strong enough to support a person’s weight. If you went bigger and used a T-shirt made of the material, it could hold the weight of a family car.
The far-out research group known as DARPA (short for the Defense Advanced Research Projects Agency) has an extremely cool Z-Man program meant to develop new climbing aids that are biologically inspired by geckos as well as by spiders and small animals. One of the Z-Man results has been the "Geckskin," developed at the University of Massachusetts, Amherst, with partial funding by DARPA.
While many efforts like BAE’s have focused on replicating the qualities of those microscopic toe hairs, called setae, to mimic their adhesive capability, this promising research has gone in a different direction.
Geckskin looks like a 16-inch square of rubber-coated fabric. It doesn’t feel sticky yet it can be used to climb supersmooth surfaces, even glass.
Relying on the Van der Waals force, which describes the attraction between molecules on the two surfaces, it can hold a maximum force of about 700 pounds while still adhering to a vertical surface. Van der Waals force is basically reversible adhesion or the electrostatic attraction of the molecules on the two surfaces.
Geckskin has already been fabricated and demonstrated proof of concept with a 16-square-inch sheet sticking to a vertical glass wall -- while holding 660 pounds.
To maximize van der Waals interaction with the surface, tests have been run on Z-Man adhesive pads that mimic the gecko foot, from the tendons through to the microscopic setae and spatula.
DARPA’s efforts are also concentrated on nano-adhesives; the agency’s goal this year is to demonstrate a soldier with operationally relevant equipment at 250 pounds climbing a 25-foot tall wall. Next year the goal the research agency aims to hand over prototypes of the nanoadhesive to the initial Service users.
According to DARPA’s budget, $20 million this year and next will be invested into the program.
Gecko-inspired technology could be used a number of different ways well beyond wall climbing. BAE Systems has been looking at other military applications, including a way to rapidly repair holes in aircraft skins or fuel tanks and a technique to instantly attach stealth or armor to vehicles.
From tethering aircraft to carrier decks through to improving robots, the defense potential from this tiny creature is immense.
Ballet dancer turned defense specialist Allison Barrie has travelled around the world covering the military, terrorism, weapons advancements and life on the front line. You can reach her at firstname.lastname@example.org or follow her on Twitter @Allison_Barrie.