The U.S. air force, realizing that every aerial battlefield in the past few decades has featured several KC-135 tankers circling, waiting to refuel a thirsty warplane, has given the tankers another job. By adding a few hundred pounds of electronics mounted on a cargo pallet, which KC-135s are equipped to handle, the tanker is turned into a node in an aerial communications network. This solves the problem of how to connect warplanes to the new battlefield Internet when those planes do not have satellite communications capability. The aircraft use line-of-sight communications, which cannot connect with any ground station or aircraft that is over the horizon or behind a mountain. The system, called ROBE (Roll-On Beyond-line-of-sight Enhancement), would be particularly useful in a mountainous area like Afghanistan. The first 20 ROBE units, costing about $900,000 each, are entering service now. The Department of Defense and NATO have already developed standards (LINK 16) for the transfer of video, picture and data electronically between ground stations, aircraft and ships using radio or satellite communications networks.