The Aerojet General X-8 was an unguided, spin-stabilized sounding rocket designed to launch a 150 lb (68 kg) payload to 200,000 feet (61.0 km). The X-8 was later spun off into the prolific Aerobee rocket.
At launch, an 18,000 lbf (80 kN) thrust Aerojet solid rocket booster fired for 2.5 seconds. After booster jettison, a 2,600 lbf (12 kN) thrust RTV-N10 liquid fuel rocket burned for up to 40 seconds (depending on desired apogee). The spent rocket then fell back in a ballistic arc, the payload returning to Earth via parachute. The baseline X-8 measured 20.2 ft (6.2 m) in length and measured 5.25 ft (1.6 m) across the fins. In testing, a maximum altitude of 138 miles (222.1 km) and a speed of Mach six was achieved.