Aerojet General X-8

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The Aerojet General X-8 was an unguided, spin-stabilized sounding rocket designed to launch a Template:Convert payload to Template:Convert.<ref>Template:Cite book</ref><ref name="Miller, Jay 1988, page 81">Miller, Jay, The X-Planes, 1988, Arlington, Texas: Aerofax, Inc., Template:ISBN, page 81</ref> The X-8 was a version of the prolific Aerobee rocket family.<ref name="Miller, Jay 1988, page 81"/><ref>Template:Cite book</ref><ref>Template:Cite book</ref>

Towards the end of World War II, the US Army and the California Institute of Technology's Jet Propulsion Laboratory had developed a meteorological sounding rocket, the WAC Corporal.<ref>Template:Cite book</ref> The U.S. Army had also captured enough parts to assemble perhaps 100 German V-2 guided missiles. The Army determined that its Project Hermes would be extended to assemble and launch a number of the V-2s for military, technological and scientific purposes.<ref>Template:Cite book</ref> Many of the V-2 components were damaged or useless.<ref>Template:Cite book</ref><ref>Template:Cite book</ref> Thus the initial intent of the Army was to launch only 20 missiles.<ref>Template:Cite book</ref>

The Army was to make space available on the V-2s for upper atmosphere research. Due to the limited number of V-2s, originally planned design of several competing sounding rockets continued. Jet Propulsion Laboratory initially favored its WAC Corporal despite its inadequacy.<ref>Template:Cite book</ref> The competing rockets were the Applied Physics Laboratory's Aerobee and the Naval Research Laboratory's Neptune (Viking).<ref>Template:Cite book</ref> The Army determined that it would refurbish and manufacture components as necessary to launch many more V-2s than originally intended, making most available for science.<ref>Template:Cite book</ref>

The Aerobee was developed in response to the need for a sounding rocket to replace the dwindling numbers of V-2s.<ref>Template:Cite book</ref> Design and initial development of the Aerobee occurred between June 1946 and November 1947.<ref>Template:Cite book</ref>

The first Aerobees, the Navy RTV-N-8a1 and Army Signal Corps XASR-SC-1, used the Aerojet XASR-1 Template:Convert thrust air-pressurized engine. Aerojet's XASR-1 was developed from the Template:Convert thrust WAC-1 engine of the WAC Corporal sounding rocket.<ref>Template:Cite book</ref> The USAF RTV-A-1 (X-8), Navy RTV-N-10 and Army XASR-SC-2s used the Aerojet XASR-2 Template:Convert thrust helium pressurized engine.<ref>Template:Cite book</ref> In 1949 the Air Force instigated the development of a more powerful Aerojet engine to replace the 2,600 lb.-thrust XASR-2. This was the Template:Convert thrust helium-pressurized AJ 10-25.<ref name="Sounding Rockets">Template:Cite book</ref> The USAF X-8A (RTV-A-1a) and USN RTV-N-10a used the seminal Aerojet AJ-10-25 (Air Force) or AJ-10-24 (Navy).<ref name="Sounding Rockets"/><ref>The AJ-10 series of rocket engines spanned 49 different versions and the history of space exploration. From the Aerobee and Vanguard, to the Able and Delta SLVs, Titan SLVs, the Apollo Service Module engine and the Space Shuttle Orbital Maneuver engine. Sutton, George P., History of Liquid Propellant Rocket Engines, American Institute of Aeronautics and Astronautics, Reston, Virginia, 2006, pages 371–377, Template:ISBN</ref>

The Army Air Force's Air Research and Development Command, needing its own research programs, initiated Project MX-1011 and ordered 33 AJ-10-25 powered Aerobees as RTV-A-1s.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> That designation was later changed to X-8.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Ultimately the rocket was renamed again as RM-84.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The number of X-8s flown came to 60 including 28 X-8s (RTV-A-1), 30 X-8As (RTVM-A-1a), 1 X-8B (RTV-A-1b) with a Template:Convert thrust XASR-2 chemically pressurized engine, and 1 X-8C (RTV-A-1c) with a Template:Convert thrust AJ 10-25s helium pressurized engine with no booster.<ref>Miller, Jay, The X-Planes, 1988, Arlington, Texas: Aerofax, Inc., Template:ISBN, page 82</ref><ref>Includes 1 flown for the SCEL as SC-31 and another flown for the same agency as SM1.01.Template:Cite book</ref> The three X-8D with Template:Convert thrust AJ 10-25, were never flown.<ref>Miller, Jay, The X-Planes, 1988, Arlington, Texas: Aerofax, Inc., Template:ISBN, page 80</ref> A Navy experimental launch of a stretched Aerobee, the RTV-N-10b resulted in both services requesting improved Aerobees, known generically as Aerobee-Hi.<ref name="Miller 1988 82">Template:Cite book</ref><ref>Template:Cite book</ref>

Operational historyEdit

At launch, an Template:Convert thrust Aerojet 2.5KS18,000G solid rocket booster fired for 2.5 seconds.<ref name="Miller 1988 80">Template:Cite book</ref> After booster jettison, a Template:Convert thrust XASR-2 liquid fuel rocket burned for up to 40 seconds (depending on desired apogee).<ref name="Miller 1988 80"/><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The X-8 recovery sequence was normally started as the rocket descended through about Template:Convert feet when the fins were blown off to induce a drag producing tumble.<ref>Template:Cite book</ref> At about Template:Convert the nose cone was blown off the rocket and returned to Earth by parachute.<ref>Template:Cite book</ref> The baseline X-8 measured Template:Convert in length and measured Template:Convert across the fins. A X-8A reached a maximum altitude of Template:Convert Another reached a speed of Mach six.<ref>Template:Cite book</ref> The payloads of the X-8s varied, averaging about 150 lbs.<ref name="Miller 1988 82"/> There were 30 X-8s, 30 X-8As, 1 X-8B, 2 X8-Cs and 3 X-8Ds delivered to the Air Force.<ref name="Miller 1988 80"/>

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.<ref>Template:Cite book</ref> USAF-1 reached an altitude of Template:Convert 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.<ref>Template:Cite book</ref>

The next four flights saw the nose cone recovery parachutes fail.<ref>Template:Cite book</ref>

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 Template:Convert before a flawless recovery.<ref>Template:Cite book</ref>

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, rocket performance, biological experiments, air density, day airglow, ionosphere, sodium studies, nitric oxide to produce a sporadic E layer, nitric oxide attempt to recombine atomic oxygen, sodium cloud ionization, solar spectrum and atmospheric composition.<ref>Template:Cite book</ref> All but the last X-8 mission were flown from Holloman AFB. The last X-8 was flown for the Signal Corps Electronic Laboratory from Fort Churchill, Canada on 11/12/1956 and studied temperature and winds.<ref name="Miller 1988 82"/> After the X-8s Air Force Aerobees were known by their engine model numbers, either AJ-10-27 or AJ-10-34.<ref>Template:Cite book</ref>