Jupiter-C

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). All were launched from Cape Canaveral, Florida. • Illustration — Meeting of the Project Orbiter Committee on 17 March 1955

• Name — Jupiter-C • Function — Sounding rocket • Manufacturer — Chrysler for the ABMA • Country Origin — United States • Height — 69.9 ft • Diameter — 5.8 ft • Mass — 64,000 lb • Stages — 3 • Status — Retired • Sites — LC-5 and 6, Cape Canaveral Missile Annex, Florida • Launches — 3 (all suborbital) • Success — 3 (suborbital) • Fail — 0 (suborbital) • Partial — 0 (suborbital) • First — September 20, 1956 • Last — August 8, 1957

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).

• 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 hydyne 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

Three Jupiter-C flights were made between 1956 and 1957. These were followed by satellite launches with the vehicle designated as Juno I. All were launched from Cape Canaveral, Florida. Jupiter-C flights • Flight No. — Date — Rocket — Launch site — Payload — Payload mass — Outcome — Comments • 1 — September 20, 1956 — Jupiter-C RS-27 (UI) — LC-5 — Microlock Beacon — 39.2 kg — Altitude of 1,100 km, speed of 7 km/s, and range of 5,300 km. • 2 — May 15, 1957 — Jupiter-C RS-34 (NT) — LC-6 — Ablative nose cone — 140 kg — Altitude of 560 km and range of 1,100 km. • 3 — August 8, 1957 — Jupiter-C RS-40 (TX) — LC-6 — 1/3-scale Jupiter nose cone — 23 kg — Altitude of 460 km and range of 2,140 km. First nosecone to be recovered from space.

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.

Jupiter-C displays: • US Space and Rocket Center, Huntsville, Alabama, with Explorer 1 mock-up • Marshall Space Flight Center, Huntsville, Alabama, with Explorer 1 mock-up • Petal, Mississippi (formerly at John C. Stennis Space Center's StenniSphere, now INFINITY Science Center, not publicly visible)