Raise Shields

We really are living in sci-fi:

Darpa, the Pentagon's wide-eyed research arm, is betting big on "metamaterials" -- composites that can seemingly-impossible new properties, thanks to their molecular structure. But even for Darpa, and even for metamaterials, this seems like a long shot: a $15 million program to build shoot-through, one-way-invisible, self-healing shields for soldiers in urban battlefields.

Metamaterials are already showing promise, as the building blocks to real-life invisibility cloaks; that's because the composites let electromagnetic waves flow around them, instead of reflecting 'em back. Darpa's "Asymmetric Materials for the Urban Battlespace" program goes way, way beyond mere invisibility, however.

"Asymmetric, or 'one-way,' materials will support basic unit operations such as raids, cordon and search activities, snap checkpoints, and fire fights," according to military budget documents. "Friendly forces will be able to see through [one of these new materials] and shoot through it, but hostile forces will not." Such shields will also have "the ability to 'self-heal' if necessary. The materials must be lightweight, respond instantly, and be easy to deploy and retract in confined spaces."