Jupiter-C
Encyclopedia
The Jupiter-C was an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 sounding rocket
Sounding rocket
A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The origin of the term comes from nautical vocabulary, where to sound is to throw a weighted line from a ship into...

 used for three sub-orbital spaceflight
Sub-orbital spaceflight
A sub-orbital space flight is a spaceflight in which the spacecraft reaches space, but its trajectory intersects the atmosphere or surface of the gravitating body from which it was launched, so that it does not complete one orbital revolution....

s in 1956 and 1957 to test re-entry nosecones that were later to be deployed on the more advanced PGM-19 Jupiter mobile missile.

A member of the Redstone rocket family
Redstone (rocket family)
The Redstone family of rockets consisted of a number of American ballistic missiles, sounding rockets and expendable launch vehicles operational during the 1950s and 60s. The first member of the family was the PGM-11 Redstone missile, from which all other members were derived. The first large U.S...

, Jupiter-C was designed by the U.S. Army Ballistic Missile Agency
Army Ballistic Missile Agency
The Army Ballistic Missile Agency was the agency formed to develop the US Army's first intermediate range ballistic missile. It was established at Redstone Arsenal on February 1, 1956 and commanded by Major General John B...

 (ABMA), under the direction of Wernher von Braun
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...

. All three flights were launched from Cape Canaveral, Florida
Cape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...

.

Description

Each vehicle consisted of a modified Redstone ballistic missile with two solid-propellant upper stages. The tanks of the Redstone were lengthened by 8 ft (2.4 m) to provide additional propellant. The instrument compartment was also smaller and lighter than the Redstone's. The second and third stages were clustered in a "tub" atop the vehicle.
The second stage was an outer ring of eleven scaled-down Sergeant
MGM-29 Sergeant
The MGM-29 Sergeant was an American short-range, solid fuel, surface-to-surface missile developed at the Jet Propulsion Laboratory. Activated by the US Army in 1962 to replace the MGM-5 Corporal it was deployed overseas by 1963, carrying the W52 nuclear warhead or alternatively one of high explosives...

 rocket engines; the third stage was a cluster of three scaled-down Sergeant rockets grouped within. These were held in position by bulkheads and rings and surrounded by a cylindrical outer shell. The webbed base plate of the shell rested on a ball bearing
Bearing (mechanical)
A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...

 shaft mounted on the first-stage instrument section. Two electric motors spun in the tub at a rate varying from 450 to 750 rpm to compensate for thrust imbalance when the clustered motors fired. The rate of spin was varied by a programmer so that it did not couple with the changing resonance frequency of the first stage during flight.

The upper-stage tub was spun-up before launch. During first-stage flight, the vehicle was guided by a gyro-controlled autopilot controlling both air-vanes and jet vanes on the first stage by means of servos. Following a vertical launch from a simple steel table, the vehicle was programmed so that it was traveling at an angle of 40 degrees from the horizontal at burnout of the first stage, which occurred 157 seconds after launch.

At first-stage burnout, explosive bolts fired and springs separated the instrument section from the first-stage tankage. The instrument section and the spinning tub were slowly tipped to a horizontal position by means of four air jets located at the base of the instrument section. When the apex of the vertical flight occurred after a coasting flight of about 247 seconds, a radio signal from the ground ignited the eleven-rocket cluster of the second stage, separating the tub from the instrument section. The third stage then fired to raise the apogee. Through this system, designed by Wernher von Braun
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...

 in 1956 for his proposed Project Orbiter
Project Orbiter
Project Orbiter was a proposed United States spacecraft, an early competitor to Project Vanguard. It was jointly run by the United States Army and United States Navy. It was ultimately rejected by the Ad Hoc Committee on Special Capabilities, which selected Project Vanguard instead...

, the Jupiter-C obviated the need for a guidance system in the upper stages.

Juno I

The Juno I
Juno I
The Juno I was a four-stage American booster rocket which launched America's first satellite, Explorer 1, in 1958. A member of the Redstone rocket family, it was derived from the Jupiter-C sounding rocket...

 was a satellite launch vehicle based on the Jupiter-C, but with the addition of a fourth stage, atop the "tub" of the third stage. The Juno name derived from von Braun wishing to make the satellite launch appear as peaceable as the Vanguard rocket
Vanguard rocket
The Vanguard rocket was intended to be the first launch vehicle the United States would use to place a satellite into orbit. Instead, the Sputnik crisis caused by the surprise launch of Sputnik 1 led the U.S., after the failure of Vanguard TV3, to quickly orbit the Explorer 1 satellite using a Juno...

, which was not a weapon, but was developed from a weather study rocket, the Viking
Viking rocket
The Viking rocket series of sounding rockets were designed and built by the Glenn L. Martin Company under the direction of the U.S. Naval Research Laboratory . Twelve Viking rockets flew from 1949 to 1955.- Origins :...

. Since the Juno I was the same height as the Jupiter-C (21.2 meters), with the added fourth stage being hidden inside the shell, this vehicle which successfully launched the first orbital satellite of the United States is often incorrectly referred to as a Jupiter-C.

General characteristics

  • Weight as configured for Explorer 1 launch, loaded/empty
    • Overall, takeoff: 64,000 lb (29,000 kg)/10,230 lb (4640 kg)
    • Stage 1 62,700 lb (28,400 kg)/9,600 lb (4,400 kg)
    • Stage 2 1,020 lb (460 kg)/490 lb (220 kg)
    • Stage 3 280 lb (130 kg)/140 lb (64 kg)
  • Propulsion
    • Stage 1: Rocketdyne
      Rocketdyne
      Rocketdyne was a Rocket engine design and production company headquartered in Canoga Park, California, United States. The company was related to North American Aviation for most of its history. NAA merged with Rockwell International, which was then bought by Boeing in December, 1996...

       A-7 engine
      • Thrust, 83,000 lbf (370 kN)
      • burning time, 155 s
      • specific impulse, 235 s (2.30 kN·s/kg)
      • propellants, liquid oxygen, as oxidizer, and "Hydyne" (60% unsymmetrical dimethylhydrazine and 40% diethylenetriamine), as fuel
      • propellant feed, turbopump type
      • turbopump drive, 90% hydrogen peroxide decomposed by catalyst bed to produce steam
    • Stage 2: Eleven JPL scaled-down Sergeant rockets
      • Thrust, 16,500 lbf (73 kN)
      • burning time, 6.5 s
      • specific impulse, 220 s (2.16 kN·s/kg)
      • propellant, polysulfide-aluminum and ammonium perchlorate (solid propellant)
    • Stage 3: Three JPL scaled-down Sergeant rockets
      • Thrust, 4,500 lbf (24 kN)
      • burning time, 6.5 s
      • specific impulse, 235 s (2.30 kN·s/kg)
      • propellant, same as for Stage 2

Flight history

  • September 20, 1956: lifted an 86.5-lb (39.2 kg) payload (including a 30-lb (14 kg) dummy satellite
    Satellite
    In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

    ) to an altitude of 680 mi (1,100 km), a speed of 16,000 mph (7 km/s), and a range of 3,300 mi (5,300 km) from Cape Canaveral
    Cape Canaveral Air Force Station
    Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...

    , Florida

  • May 15, 1957: lifted a 300 lb (140 kg) scale Jupiter ablative nose cone to an altitude of 350 mi (560 km) and a range of 710 mi (1,100 km)

  • August 8, 1957: lifted a 1/3-scale Jupiter nose cone to an altitude of 285 mi (460 km) and a range of 1,330 mi (2,140 km); Juno I (four-stage configuration).
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