The Perimeter Acquisition Radar performed long-range surveillance, detection, and tracking of intercontinental ballistic missiles for interception, scanning more than 1,000 miles over the North Pole for incoming missiles and handing identified threats to the Missile Site Radar while continuing to scan. The Missile Site Radar and Data Processor refined tracking data for interception and could have launched and guided Spartan or Sprint missiles against incoming missiles. The fifty-five-foot Spartan would have been launched from an underground silo at the co-located missile field, with its flight controlled by the Missile Site Computer through commands from the Missile Site Radar; its radar-controlled flight plan used three solid-propellant-powered stages with two in-flight separations, and it was designed for long-range interception outside the atmosphere with a warhead in the megaton range. The twenty-seven-foot Sprint missile was short range, fast, and designed for interception within the atmosphere, able to reach intercept within seconds after launch; it would have been ejected from an underground cell by a gas-propelled piston, with its booster igniting once in the air, and it carried a warhead in the kiloton range. In addition to the Perimeter Acquisition Radar and Missile Site Radar, the Safeguard System included four Remote Sprint Launch Sites, each located within twenty to twenty-five miles of the Missile Site Radar; these sites effectively extended Sprint missile range to about seventy nautical miles, and each forty-acre site contained a hardened Remote Launch Operations Building, twelve to sixteen Sprint Missile Launch Stations, and several other support components. Besides extending the system's range, the Remote Sprint Launch Sites also provided redundancy in the event of a direct hit at the Missile Site Radar site, and Sprint missiles could be launched from the co-located missile field or any of the four Remote Sprint Launch Sites.