It was built on the airframe of the RIM-66 Standard surface-to-air missile, resulting in a very large weapon with considerable range, allowing it to attack targets as much as 50 miles (80 km) away.

[1] The first version of the missile, the AGM-78A-1 or STARM Mod 0, was little more than an air-launched RIM-66 with the Shrike's anti radar seeker head attached to the front.

Of equal size, mass and shape, the missile lacked a seeker head, warhead, or propulsion systems and was essentially just a dead weight.

A simple memory circuit was also included, allowing the missile to attack a target once it locked on, even if the radar was shut down.

Previous ARMs would veer off course and miss when they lost a target, and as a result flipping the radar on and off had become a standard tactic for missile batteries.

A follow-up missile, the AGM-78D-2, had an active optical fuze, still greater reliability, and a new 100 kg (220 lb) blast-fragmentation warhead.