The X-17 was a multistage vehicle using available and proven rocket motors and a relatively simple control system. The X-17 was powered by three solid-propellant rocket stages. The first stage, consisting of a single Thiokol XM20 Sergeant motor, had four stabilizing fins and two small external (strap-on) spin motors, which were jettisoned shortly after launch. After first stage shutdown, the missile coasted to an apogee of about 150 km (500000 ft), where it pitched over for a nose-down reentry. At an altitude of around 21 - 27 km (70000 - 90000 ft), the first stage was separated, immediately followed by firing of the short duration second and third stage motors. At burnout of the final stage, the X-17 had reached a speed between Mach 11 and Mach 14.5, depending on reentry angle. Equipment of the missile included a telemetry system and an AN/DPN-19 radar beacon to facilitate tracking.
(US Air Force photo)