thrust AJ 10-25s helium pressurized engine with no booster. The three X-8D with thrust AJ 10-25, were never flown. A Navy experimental launch of a stretched Aerobee, the RTV-N-10b resulted in both services requesting improved Aerobees, known generically as Aerobee-Hi. Operational history At launch, an thrust Aerojet 2.5KS18,000G solid rocket booster fired for 2.5 seconds. After booster jettison, a thrust XASR-2 liquid fuel rocket burned for up to 40 seconds (depending on desired apogee). The X-8 recovery sequence was normally started as the rocket descended through about feet when the fins were blown off to induce a drag producing tumble. At about the nose cone was blown off the rocket and returned to Earth by parachute. The baseline X-8 measured in length and measured across the fins. A X-8A reached a maximum altitude of Another reached a speed of Mach six. The payloads of the X-8s varied, averaging about 150 lbs. There were 30 X-8s, 30 X-8As, 1 X-8B, 2 X8-Cs and 3 X-8Ds delivered to the Air Force. The first RTV-A-1 (X-8) flight was USAF-1, flown at Holloman Air Force Base (adjacent to the White Sands Proving Ground). USAF-1 was launched by an Air Force crew commanded by Major Phillip Calhoun, the Aerobee Project Officer, on 2 December 1949. USAF-1 reached an altitude of and carried three experiments; a Solar Radiation Soft X-Ray detector for the Air Force Cambridge Research Center, a Pressure-Temperature study for Boston University, and a Color Earth Photography experiment for the Wright-Patterson Air Force Base Equipment Laboratory. Rocket performance was good. Telemetry returned some data. The X-Ray detector foils ruptured and returned no data. Parachute failure resulted in the nose cone containing the experiments to be lost. The nose cone was found in July 1950, the film was destroyed. The next four flights saw the nose cone recovery parachutes fail. USAF-6, was a more typical X-8 Mission. It carried a payload of Pressure-Temperature detectors for the University of Michigan, an Air Force Cambridge Center multipurpose beacon, 6 channel PPM-AM system, a Ten channel data recorder supplied by Tufts College, and a camera to photograph a Sperry aspect gyro for the University of Michigan. USAF-6 reached an altitude of before a flawless recovery. From December 1949 until the last X-8A flight on 11/12/1956, the X-8s (RTV-A-1/RTV-A-1a)s flew a great variety of experiments. Typical payloads were solar radiation, temperature, pressure, photography, sky brightness, atmosphere composition, winds, airglow,