 They suggested that the conversion would be simple, but the missile's long lock-on time and optical guidance would make it ineffective in close combat.Based on this potential solution to the air defense problem, the Army Staff, supported by the Army Air Defense Artillery School at Fort Bliss, started a new study under the direction of Lieutenant Colonel Edward Hirsch.Known as the "Interim Field Army Air Defense Study", it called for a multi-layer system consisting of an adapted Sidewinder as a missile component known as the MIM-72 Chaparral, a short-range gun component using the M61 Vulcan known as the M163 VADS, and the separate AN/MPQ-49 Forward Area Alerting Radar that would support both by sending digital information to displays in those platforms.