Directory of U.S. Military Rockets and Missiles|
Appendix 4: Undesignated Vehicles
|Copyright © 2005 Andreas Parsch|
In 1955, the USA announced plans to put a scientific satellite in orbit for the International Geophysical Year (IGY) in 1957/58. At that time there were three possible candidates for the launch vehicle: the Air Force's SM-65 Atlas, a derivative of the Army's SSM-A-14 Redstone, and a Navy proposal for a three-stage rocket based on the RTV-N-12a Viking sounding rocket. However, the Atlas and Redstone ballistic missiles were top-priority military projects, which were not to be slowed by pursuing a secondary space launch mission. Therefore the Navy's project, named Vanguard, was selected in September 1955 as the first satellite launch vehicle of the USA. The Martin company, which had also built the Viking, became prime contractor for the launch vehicle.
Politics also played a major role in the selection of Vanguard. The Army's Redstone-based proposal would likely be ready earlier for a first satellite launch. However, Vanguard was a project of the NRL (Naval Research Laboratory), which was regarded more as a scientific than a military organization. This helped to emphasize the non-military goals of the satellite program. This was considered important, because a discussion whether overflights of foreign countries by satellites were legal or not was to be avoided.
The Vanguard rocket was designed as a three-stage vehicle. The first stage was a General Electric X-405 liquid-fueled engine (designated XLR50-GE-2 by the Navy), derived from the engine of the RTV-N-12a Viking. The second stage was the Aerojet General AJ10-37 (XLR52-AJ-2) liquid-fueled engine, a variant of the engine in the RTV-N-10 Aerobee. Finally, the third stage was a solid-propellant rocket motor. All three-stage Vanguard flights except the last one used a motor built by the Grand Central Rocket Company. Vanguard had no fins, and the first and second stages were controlled by gimballed nozzles. The second stage also housed the vehicle's telemetry system, the inertial guidance system and the autopilot. The third stage was spin stabilized, the spin being imparted by a turn-table on the second stage before separation.
The first two flights of the Vanguard program, designated Test Vehicle (TV)-0 and -1, were actually the last two remaining RTV-N-12a Viking rockets. TV-0, launched on 8 December 1956, primarily tested new telemetry systems, while TV-1 on 1 May 1957 was a two-stage vehicle testing separation and ignition of the solid-fueled upper stage of Vanguard. TV-2, launched on 23 October 1957 after several abortive attempts, was the first real Vanguard rocket. The second and third stages were inert, but the flight successfully tested 1st/2nd-stage separation and spin-up of the third stage. However, by that time, the Soviet Union had already placed the "Sputnik" satellite into orbit, and therefore project Vanguard was more or less forced to launch its own satellite as soon as possible. Therefore, a very small experimental satellite (called the "grapefruit" and weighing only 1.8 kg (4 lb)) was added to TV-3, which was to be the first test of an all-up Vanguard rocket. Although the NRL and Martin tried to emphasize that the TV-3 mission was a pure test flight (and one with several "firsts"), everyone else saw it as the first satellite launch of the Western world. When TV-3 exploded a few seconds after lift-off on 6 December 1957, this was accordingly viewed, at least in the eye of the general public, as a major embarrassment and a disaster for the U.S. space program.
Flight TV-3BU (BU = Backup) on 5 February 1958 broke up after 57 seconds because of a control system malfunction, but TV-4 on 17 March finally succeeded in placing a "Grapefruit"-type satellite into orbit. By that time, however, the Army's Juno (Jupiter C) had already launched the United States' first satellite. The TV-4 satellite, labeled Vanguard 1, had reached a relatively high orbit (3966 km (2465 miles) x 653 km (406 miles)) and is currently the oldest human artifact in space.
The following four flights, TV-5 and SLV (Satellite Launch Vehicle)-1 through -3 all failed, but on 17 February 1959, SLV-4 launched Vanguard 2 (weighing 10.8 kg (23.7 lb)) into orbit. The SLVs were the "production" Vanguard rockets. SLV-5 and -6 failed again, but the final flight on 18 September 1959 successfully orbited the 23.6 kg (52 lb) Vanguard 3 satellite. That last mission was designated TV-4BU, because it used a remaining test vehicle, which had been upgraded with a new third stage, the Allegheny Ballistics Lab X-248A2 Altair. This more powerful motor enabled the launch of the heavier payload. The combination of the AJ10 liquid engine and X-248 solid motor was also used, under the name Able, as an upper stage combination for Thor and Atlas space launch vehicles.
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for Vanguard:
|Length||22.15 m (72 ft 8 in)|
|Diameter||1st stage: 1.14 m (45 in)|
2nd/3rd stage: 81 cm (32 in)
|Weight||10250 kg (22600 lb)|
|Payload||10.8 kg (23.7 lb) to LEO|
|Propulsion||1st stage: General Electric X-405 (XLR50-GE-2) liquid-fueled rocket; 120 kN (27000 lb) for 144 s|
2nd stage: Aerojet General AJ10-37 (XLR52-AJ-2) liquid-fueled rocket; 33 kN (7500 lb) for 122 s
3rd stage: Grand Central 33KS2800 solid-fueled rocket; 12.5 kN (2800 lb) for 33 s
 Constance McLaughlin Green & Milton Lomask:
"Vanguard: A History", NASA, 1970
 Peter Alway: "Rockets of the World", Saturn Press, 1999
 T.A. Heppenheimer: "Countdown: A History of Space Flight", Wiley, 1997
 Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
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