Starting in 1959 the U.S. Army MICOM (Missile Command) began development of an ambitious anti-aircraft missile system under their "Forward Area Air Defense" (FAAD) program, known as the MIM-46 Mauler. Mauler was based on a modified M113 chassis carrying a large rotating A-frame rack on top with nine missiles and both long-range search and shorter-range tracking radars. Operation was to be almost entirely automatic, with the operators simply selecting targets from the search radar's display and then pressing "fire". The entire engagement would be handled by the fire control computer.
In testing the Mauler proved to have numerous problems. Many of these were relatively minor, including problems with the rocket motors or fins on the airframe, but others, like problems with the fire control and guidance systems, appeared to be more difficult to solve. Army strategy from the mid-1950s PENTANA study was based on having embedded mobile anti-aircraft capability, and Mauler's delays put this entire program in question. More worrying, a new generation of Soviet attack aircraft was coming into service. For both of these reasons the Mauler program was scaled back in 1963 and alternatives were studied.
MICOM was directed to study whether or not the Navy's AIM-9D Sidewinder missile could be adapted for the ground-to-air role. Since the Sidewinder was guided by an infrared seeker, it would not be confused by ground clutter like the radar-guided Mauler. On the downside, the missile required some time to "lock on", and the current generation seekers were only able to lock onto the tail of an aircraft. MICOM's report was cautiously optimistic, concluding that the Sidewinder could be adapted very quickly, although it would have limited capability.
A new concept, the "Interim Forward Area Air Defense" (IFAAD) evolved around the Sidewinder. The main concern was that at shorter distances the missile would not have time to lock onto the target before it flew out of range, so to serve this need a second vehicle based around the M61 Vulcan cannon was specified. Both would be aimed manually, eliminating the delay needed for a fire control system to develop a "solution". Neither vehicle concept had room for a search radar, so a separate radar system using datalink was developed for this role.
The studies were completed in 1965 and the Chaparral program was begun. The first XMIM-72A missiles were delivered to the US Army in 1967. Ford developed the M730 vehicle, adapted from the M548, itself one of the many versions of the widely used M113. The first Chaparral battalion was deployed in May 1969.