AVIATION An Internet in the sky could let planes fly safely withoutground controllers. Of the numerous technologies now in
gestation at companies and universities,we have chosen 10 that we think will make particularly big splashes. They'reraw, but they'll transform the Internet, computing, medicine, energy,nanotechnology, and more. The technology that underpins the air
traffic control system hasn't changedmuch in a half-century. Planes still depend on elaborate ground-based radarsystems, plus thousands of people who watch blips on screens and issue verbalinstructions, for takeoffs, landings, and course changes. The system isexpensive, hard to scale up, and prone to delays when storms strike.An entirely different approach is possible. Each plane could continuallytransmit its identity, precise location, speed, and heading to other planes inthe sky via an airborne network. Software would then take over, coördinatingthe system by issuing instructions to pilots on how to stay separated, optimizeroutes, avoid bad weather, and execute precise landings in poor visibility.In the near term, such technology could save travelers time and might reducefuel consumption. Long term, it could revolutionize air travel by enabling moreplanes to fill the sky without the addition of infrastructure and staff. Vastlygreater numbers of small planes could zip in and out of thousands of smallairfields (there are 5,400 in the U.S. alone), even those with noradar at all. The biggest holdback to the number of airplanes that can be inthe sky is that air traffic controllers are separating aircraft by hand, saysSally Johnson, an aerospace engineer at NASA's Langley
Research Center. Until you getaway from that paradigm, we are at the limits of what you can do.As a practical matter, airborne networks that rely on software and cockpitcomputers rather than humans to issue instructions are still decades away. Butin June, NASA plans to demonstrate a prototype of such an automated system at asmall airport in Danville, VA. A computer at a ground station near theairport will receive data from multiple planes and give the pilots theirinitial holding fixes, then tell them what planes they're following and whereto go if they miss their approaches. In the planes, cockpit displays will showpilots where the other planes are, and a computer will give them instructionsthat guide their trajectories.Future systems might go further: planes would communicate not just via acomputer on the ground (or via satellite) but directly with each other,relaying information from other planes in an Internet-like fashion. Thisradical advance in airborne networking could come from research funded by thePentagon -- the midwife of today's terrestrial Internet. The vision is that notonly navigational data but information about targets, real-time intelligence,and bombing results would flow freely among manned and unmanned militaryplanes, to vehicles on the ground, and up and down chains of command. There isa terrestrial backbone of hardwired connections, and there will be a spacebackbone between satellites. What we are talking about adding, for aircraft, isan equivalent third backbone in the sky, says Dave Kenyon, division chief ofthe Technical Architectures Division at the U.S. Air Force Electronic SystemsCenter in Bedford, MA.The U.S. Air Force is beginning to define the architecture of an airbornenetwork and hopes to begin actively developing and testing the network itselfbetween 2008 and 2012, Kenyon says. Taken together, the military research andthe related air traffic control research into airborne communications networkscould change how we travel in the decades to come.