How can ground-based radars be improved? Throughout the U.S. Army Space and Missile Defense Command/Army Forces Strategic Command and its predecessors' history, this question has resulted in everything from new technologies and applications to innovative improvements to component hardware and software.Thirty years ago, on July 31, 1984, the Ballistic Missile Defense Systems Command, BMDSCOM, awarded a new demonstration contract for an Airborne Optical Adjunct, AOA, to answer that question.The AOA, later renamed the Airborne Surveillance Testbed, AST, was, as the name implies, an airborne sensor designed "to examine how an airborne optical adjunct can be used to augment ground-based radars for detection and tracking of intercontinental ballistic missiles, discriminating real warheads from decoys, and handover of track to the ground-based radars." The restrictions of the Anti-Ballistic Missile treaty precluded direct communications between the sensor system and an interceptor, but permitted the transfer of data from a secondary subsystems to a ground-based radar.Three companies produced concepts in response to the request for proposal for a five-year research demonstration program. After a period of evaluation, BMDSCOM awarded the initial cost plus award fee contract, valued at more than $289 million, to a contractor team headed by Boeing Aerospace Company. Boeing was responsible for "developing a suitable airborne platform, optical sensors, signal processors, data processor and auxiliary equipment."The two major subcontractors, Aerojet Electro Systems and Hughes Aircraft Company, meanwhile focused upon developing two separate long-wave infrared sensors that would be installed aboard the modified commercial jet. Due to cost overruns, the program was later restructured and only the sensor developed by Hughes Aircraft would be constructed and installed.The research program would ultimately test the feasibility of using these sensitive infrared sensors, capable of detecting the heat of a human body at a distance ofmore than 1,000 miles, in the missile defense program. Under the original test program, Air Force ICBM launches from Vandenberg Air Force Base, Calif. toward the U.S. Army Garrison Kwajalein Atoll Missile Range provided targets of opportunity for these airborne tests.The AOA/AST has continued to advance missile defense researching and testing into the 21st century.