PGM-19 Jupiter
In 1954, the US Army asked Rocketdyne to build an engine with a thrust of 135,000 pounds. This request came as Wernher von Braun's team at Redstone Arsenal began planning an upgrade to their existing Redstone missile. The new design would use the LR89 rocket engine and add a second stage to reach distances far beyond the Redstone's capabilities. By combining this powerful engine with lighter nuclear warheads, engineers could create a single-stage missile capable of striking targets hundreds of miles away. The project faced immediate competition from the US Navy, which wanted to develop its own sea-based version. Admiral Arleigh Burke pushed for rapid development after his appointment in August 1955. He believed the Navy needed to enter the missile field quickly to counter Air Force dominance. Secretary of Defense Charles Erwin Wilson approved both programs on the 8th of November 1955. The Army received designation IRBM No. 2 while the Air Force took IRBM No. 1. The Navy initially planned to launch Jupiter missiles from converted ships but eventually withdrew from the program in December 1956. This decision allowed them to focus entirely on developing the Polaris submarine-launched ballistic missile system.
The PGM-19 Jupiter measured 60 feet long and 8 feet 9 inches in diameter. It weighed over 108,000 pounds when fully fueled with liquid oxygen and kerosene propellants. A single Rocketdyne LR79-NA engine produced 150,000 pounds of thrust during operation. The guidance system used an inertial navigation model ST-90 that achieved a circular error probable of about 4,925 feet at maximum range. This accuracy represented four times better performance than existing Air Force systems. The missile carried a W49 nuclear warhead weighing approximately 1,650 pounds with a yield of 1.45 megatons. Fuel tanks held 30,415 pounds of RP-1 kerosene and 68,760 pounds of liquid oxygen. The entire vehicle could be prepared for launch within 15 minutes once positioned upright on its launcher. Crews operated from mobile trailers containing all necessary equipment including power distribution trucks and fueling vehicles. Each squadron required roughly 500 military personnel to maintain operational readiness across multiple sites separated by thirty miles.
The first Jupiter test flight occurred on the 1st of March 1957, from Cape Canaveral's LC-5 pad. Control failures caused the missile to break apart seventy-three seconds into the launch sequence. Engineers discovered that turbopump exhaust was being sucked back into the tail section where it burned through control wiring. A second attempt on April 26 failed again when propellant slosh destabilized the vehicle during steering maneuvers. These early problems led to five months of testing pauses while Rocketdyne redesigned critical components. By the 18th of May 1958, engineers successfully flew AM-5 reaching its planned distance after installing new baffles in both fuel tanks. Biological experiments began in December 1958 when a squirrel monkey named Gordo died after his recovery parachute failed to deploy. Two monkeys survived a later flight aboard AM-18 on the 28th of May 1959, though Able died four days post-flight due to anesthesia complications. The final test failure occurred the 15th of September 1959, when a nitrogen bottle leak caused immediate loss of control and vehicle breakup. This particular launch damaged an adjacent Juno II rocket and killed all biological specimens onboard.
President Eisenhower authorized deployment plans for three Jupiter squadrons in France during April 1958. French President Charles de Gaulle refused these basing rights just two months later forcing US planners to relocate operations. Italy agreed to host two squadrons totaling thirty missiles at ten different sites between 1961 and 1963. Turkish Air Force personnel operated one squadron of fifteen missiles near İzmir from late 1962 until removal in 1963. Lightning strikes hit four operational missiles carrying nuclear warheads between October 1961 and August 1962. These incidents activated thermal batteries and injected boost gas into warhead pits creating partial arming conditions. Protective lightning diversion towers were installed at all Italian and Turkish sites following the fourth strike. A Bulgarian MiG-17 reconnaissance aircraft crashed into an olive grove near one Italian launch site after overflying the area. Each missile required approximately twenty support vehicles including generator trucks and liquid oxygen transporters. Crews maintained readiness by keeping fuel tanks empty while storing missiles upright on launch pads ready for rapid refueling.
The removal of Jupiter missiles from Turkey became a key diplomatic trade-off during the Cuban Missile Crisis of October 1962. Soviet Premier Nikita Khrushchev had previously threatened to place similar weapons in Cuba if American missiles remained stationed in Turkey. President John F. Kennedy secretly agreed to withdraw the Jupiter systems as part of a broader negotiation strategy. All Jupiter MRBMs were officially removed from service by April 1963 following this backdoor agreement with Moscow. The missiles represented significant strategic value despite being largely obsolete by that time. Their presence had created vulnerability to potential Soviet attacks given their fixed emplacement locations. The exchange allowed both superpowers to reduce immediate tensions while maintaining nuclear deterrence capabilities elsewhere. This arrangement demonstrated how tactical weapons could become central to global crisis management decisions.
Engineers modified Jupiter missiles to create the Juno II space launch vehicle used for early satellite missions. Fourteen successful launches occurred between December 1958 and May 1961 using clustered Sergeant-derived upper stages. Pioneer 3 achieved partial success as America's first lunar probe attempt on the 6th of December 1958. Explorer satellites including numbers 7 through 12 utilized Juno II configurations for scientific observations. Six out of ten total launches failed due to technical malfunctions or premature stage cutoffs. The Saturn I rocket later adopted tooling from Jupiter production lines creating a central tank surrounded by eight Redstone-derived tanks. These modifications enabled future moon landing programs by establishing reliable liquid oxygen and kerosene propulsion systems. Several surviving examples now display at museums including Kennedy Space Center and Marshall Space Flight Center in Huntsville Alabama. One Jupiter damaged by Hurricane Frances in 2004 was repaired and returned to public exhibition status.
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Common questions
What was the thrust of the PGM-19 Jupiter engine?
A single Rocketdyne LR79-NA engine produced 150,000 pounds of thrust during operation. This powerful output allowed engineers to create a single-stage missile capable of striking targets hundreds of miles away.
When did the first test flight of the PGM-19 Jupiter occur?
The first Jupiter test flight occurred on the 1st of March 1957 from Cape Canaveral's LC-5 pad. Control failures caused the missile to break apart seventy-three seconds into the launch sequence due to turbopump exhaust burning through control wiring.
Where were the PGM-19 Jupiter missiles deployed in Europe?
Italy agreed to host two squadrons totaling thirty missiles at ten different sites between 1961 and 1963. Turkish Air Force personnel operated one squadron of fifteen missiles near İzmir from late 1962 until removal in 1963.
Why were the PGM-19 Jupiter missiles removed from Turkey?
The removal of Jupiter missiles from Turkey became a key diplomatic trade-off during the Cuban Missile Crisis of October 1962. President John F. Kennedy secretly agreed to withdraw the systems as part of a broader negotiation strategy with Soviet Premier Nikita Khrushchev.
How many successful launches did the Juno II space vehicle achieve using modified PGM-19 Jupiter missiles?
Fourteen successful launches occurred between December 1958 and May 1961 using clustered Sergeant-derived upper stages. Pioneer 3 achieved partial success as America's first lunar probe attempt on the 6th of December 1958 while Explorer satellites utilized these configurations for scientific observations.