Ghost soldiers

Some amazing sci-fi-like technologies can languish for years in the research phase. But occasionally an organization like the U.S. Army pushes a technology from the lab to the field simply by asking for it. And what the Army has just asked for is pretty amazing: an invisibility cloak.

Last month, the U.S. Army issued a request for proposals (RFP) for a wearable camouflage uniform that would make a soldier essentially indistinguishable from the surrounding background—virtual invisibility. Companies submitting proposals will have to demonstrate the feasibility of their approach within six months, and then submit 10 prototype uniforms for a one-year testing phase.

According to a report in New Scientist, the technology behind the invisibility camouflage will likely be based on what are called metamaterials—microscopic engineered structures that can bend light around an object.

“Complete invisibility of macroscopic objects for all visible colors is fundamentally impossible,” Martin Wegener of the Karlsruhe Institute of Technology in Germany told New Scientist. His team has created cloaks from photonic crystals that work for certain wavelengths, but bending light over the entire spectrum would violate Einstein’s theory of relativity.

Wegener told New Scientist that the wearer of an invisibility cloak would be effectively transparent at some wavelengths but not all, rendering the wearer almost a colored shadow or ghost image.

“How a material affects light falling upon it is dictated in part by its chemical composition, but its internal structure can have an even stronger influence,” writes John Pendry, a professor of physics at Imperial College London and one of the pioneers of the theory of metamaterials, in New Scientist. He says metamaterials extend this concept with artificial structures that might be only nanometers in diameter for visible light. “Their properties are engineered by manipulating their structure rather than their chemical composition.”

According to the Army’s solicitation, the cloaking camouflage must function across extremes of temperature and weather, work in all terrain from all angles, and not impede a soldier performing normal duties. If a prototype requires a power source, it must weigh no more than 2 pounds and provide at least four hours of power.

Smart luggage

You can check in for your airline flight online and even download a boarding pass from the comfort of your home. But if you’re checking bags, you’ll still have to wait in that long, snaking line at the airport to get them weighed and checked onto the plane. Wouldn’t it be great if your luggage could check itself in?

The smart suitcase of the future may be able to do just that—and more.

Hong Kong–based luggage manufacturer Samsonite is working with Emirates, Lufthansa, and Air France–KLM to develop a bag that self-checks at the airport. As you arrive, a microchip embedded in your luggage identifies you as the owner. It is remotely programmed with your trip details such as airline, flight numbers, and destination. All you’d have to do is toss it onto a conveyor and head to your gate.

The Daily Mail reports that Samsonite is also working with Samsung on GPS-enabled smart luggage that can tell you where your bag is at all times, alert you if you stray too far away from it or when someone tampers with it, and even propel itself alongside you as you walk. —M.C.