Redstone version
Redstone Jupiter-A
Jupiter-A was the first Redstone variant to fly: a flying testbed with no payload of its own, used to qualify components intended for the PGM-19 Jupiter medium-range missile. Twenty-five were launched from Cape Canaveral between September 1955 and June 1958, with a failure rate that says a good deal about what inertial guidance development cost at the time.
- September 22, 1955
- First launch
- No
- Reusable
History
A missile lent to another programme
When the Army began work on the far larger Jupiter medium-range missile, it needed a cheap and readily available airframe to flight-test the new hardware. The Redstone was exactly that. Reworked and fitted with Jupiter equipment, it became the Jupiter-A, built by Redstone Arsenal and Chrysler in the mid-1950s and, in practice, the first Redstone derivative to leave the pad.
What rode on the flights
The programme qualified the ST-80 inertial guidance platform, Jupiter angle-of-attack sensors, warhead fuzing systems and the explosive bolts used for separation. It also tracked the engine's evolution: the first two vehicles flew with the Rocketdyne 75-110 A-3, the A-4 took over from March 1956 and the A-6 made its flight debut in October 1957, the A-5 never having entered service. One round, RS-22, was given over to testing Hydyne fuel in an A-4 — the blend the Jupiter-C would later adopt.
A hard scorecard
Of the twenty-five attempts flown from Launch Complexes 5 and 6, close to half failed, including flights cut short by ground command after gyro trouble. That record is part of the programme's value: each failure fed design changes into the Jupiter and, along the way, into the operational Redstone itself. The last Jupiter-A flew in June 1958, by which time Jupiter-C and Juno I had taken over the family's flying.