The Jupiter-C was an American research and development vehicle[1][2] developed from the Jupiter-A.[3] Jupiter-C was used for three uncrewed sub-orbital spaceflights in 1956 and 1957 to test re-entry nosecones that were later to be deployed on the more advanced PGM-19 Jupiter mobile missile. The recovered nosecone was displayed in the Oval Office as part of President Dwight D. Eisenhower's televised speech on November 7, 1957.[4]

Jupiter-C on the launch pad at Cape Canaveral
FunctionSounding rocket
ManufacturerChrysler for the ABMA
Country of originUnited States
Height69.9 feet (21.3 m)
Diameter5.8 feet (1.8 m)
Mass64,000 pounds (29,000 kg)
Payload to Sub-orbital
Mass11 kg (24 lb)
Launch history
Launch sitesLC-5 and 6, Cape Canaveral Missile Annex, Florida
Total launches3 (all suborbital)
Success(es)1 (suborbital)
Failure(s)1 (suborbital)
Partial failure(s)1 (suborbital)
First flightSeptember 20, 1956
Last flightAugust 8, 1957
First stage – Redstone (stretched)
Powered by1 North American Aviation (Rocketdyne) 75-110-A-7
Maximum thrust93,560 lbf; 416.18 kN (42,439 kgf)
Specific impulse235 s (2.30 km/s)
Burn time155 s
Second stage – Sergeant cluster
Powered by11 Solid
Maximum thrust16,500 lbf; 73.4 kN (7,480 kgf)
Specific impulse214 s (2.10 km/s)
Burn time6 s
Third stage – Sergeant cluster
Powered by3 Solid
Maximum thrust2,040 kgf (4,500 lbf; 20.0 kN)
Specific impulse214 s (2.10 km/s)
Burn time6 s

A member of the Redstone rocket family, Jupiter-C was designed by the U.S. Army Ballistic Missile Agency (ABMA), under the direction of Wernher von Braun.[5] Three Jupiter-C flights were made. These were followed by satellite launches with the vehicle designated as Juno I (see Juno I below or the Juno I article).[6][7] All were launched from Cape Canaveral, Florida.

Description edit

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.

Redstone, Jupiter-C and Mercury-Redstone rockets compared
Second stage cluster

The second stage was an outer ring of eleven scaled-down Sergeant 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 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.[8]

The upper-stage tub was visibly 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.[9]

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 in 1956 for his proposed Project Orbiter, the Jupiter-C obviated the need for a guidance system in the upper stages.[10]

Juno I edit

The Juno I 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 and the use of Hydyne as fuel. The Juno name derived from Von Braun wishing to make the satellite launch appear as peaceable as the Vanguard rocket, which was not a weapon, but was developed from a weather study rocket, the Viking. 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.

Encrypted serial number edit

The Jupiter-C was part of the IRBM project, and the sequence of manufacture of the rockets (which are not necessarily launched in order, and may be uprated as solutions to technical problems are worked out in tests) was considered a military secret. So the designation painted on the sides of the rocket was not a serial number in clear text, but employed a simple transformation cypher that the staff would be sure not to forget. The key was taken from the name of the design and test base: Huntsville, Alabama, giving HUNTSVILE, with duplicated letters dropped: H was used for 1, U for 2, ..., E for 9 and X for 0. For example, the Jupiter-C / Juno I modified to launch Explorer 1 had "UE" painted on the side, indicating it was S/N 29 (U→2, E→9).[11][12]

General characteristics edit

  • 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 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 alcohol as fuel
      • propellant feed, turbopump type
      • turbopump drive, 90% hydrogen peroxide decomposed by catalyst bed to produce steam
    • Stage 2: Eleven JPL scaled-down Baby 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 Baby 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 edit

  • September 20, 1956: Jupiter-C RS-27, lifted an 86.5-lb (39.2 kg) payload (including a 30-lb (14 kg) dummy satellite) 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, Florida.[5][13]
  • May 15, 1957: Jupiter-C RS-34, 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).[5][13]
  • August 8, 1957: Jupiter-C RS-40, 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).[5][13]

References edit

  1. ^ "Redstone Arsenal Historical Information – 1957". United States Army. Archived from the original on 2015-05-18. Retrieved 2015-05-15.
  2. ^ "Redstone Arsenal Historical Information – Jupiter". United States Army. Archived from the original on 2015-05-18. Retrieved 2015-05-15.
  3. ^ "Rockets and Missiles". Retrieved 2018-04-19.
  4. ^ Yanek Mieczkowski, 'Cheerleader in Chief, in Eisenhower’s Sputnik Moment: The Race for Space and World Prestige, pp. 105–106.
  5. ^ a b c d "Jupiter-C Explorer-I". NASA.
  6. ^ "Redstone Arsenal Historical Information – Redstone Rocket". United States Army. Archived from the original on 2015-05-18. Retrieved 2015-05-15.
  7. ^ "Redstone Arsenal Historical Information – Explorer I". United States Army. Archived from the original on 2015-07-03. Retrieved 2015-05-15.
  8. ^ "ABMA Juno I". Retrieved 2013-03-25.
  9. ^ Juno V Space Vehicle Development Program Report No. DSP-TM-10-58, NASA, October, 1958.
  10. ^ Juno V Space Vehicle Development Program Status Report, DSP-TM-11-58, NASA, November, 1958.
  11. ^ "Rockets and Missiles / Jupiter C Fact Sheet". Retrieved 2018-04-19.
  12. ^ "SP-4402 Origins of NASA Names". Retrieved 2018-12-26.
  13. ^ a b c "Jupiter-C". Gunter's Space Page. Retrieved 2023-10-14.

Bibliography edit

West, Doug (2017). Dr Wernher von Braun: A Short Biography. US. ISBN 978-1-9779279-1-0.{{cite book}}: CS1 maint: location missing publisher (link)