PGM-19 Jupiter

• 1. Introduction

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  On the 1st of March 1957, the first PGM-19 Jupiter lifted off from Cape Canaveral and broke apart seventy-three seconds into its flight. That failure was the most fitting beginning for a program defined by contradiction. The Jupiter was the United States' first nuclear-armed medium-range ballistic missile. It was built to carry a 1.44 megaton warhead across 1,500 miles to targets in the Soviet Union. Its prime contractor was Chrysler Corporation, and its single Rocketdyne engine produced 150,000 pounds of thrust by burning kerosene and liquid oxygen. The Army designed it. The Navy helped determine its dimensions. The Air Force ultimately operated it, having arrived at that outcome against its will. The production missiles eventually rolled out of Chrysler's plant near Warren, Michigan. By then, the arguments over who should aim them had consumed most of the decade.

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• 2. Feuding Services

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  Wernher von Braun's Army Ballistic Missile Agency at Redstone Arsenal in Alabama traced Jupiter's origins to the PGM-11 Redstone, the country's first nuclear ballistic missile. While Redstone was entering service, the team imagined a longer-range successor. An improved Rocketdyne engine, combined with an upper stage, could push range to 1,000 nautical miles. As nuclear warhead weights dropped in the early 1950s, a simpler approach emerged. By pairing a single powerful engine with a 2,000-pound warhead, they could build a one-stage missile far easier to handle in the field. In 1954, the Army asked Rocketdyne to design an engine producing 135,000 pounds of thrust. The design kept improving and ultimately reached 150,000 pounds of thrust in the model designated the S-3D.

  The Air Force opposed the project from its inception. Their case was strategic, not technical. Any missile with Jupiter's range could reach Soviet cities, and no launch could be clearly identified as targeting a military rather than a civilian site. The Air Force insisted any such launch would be read as the opening of a full strategic exchange. Secretary of Defense Charles Erwin Wilson could not secure a unified recommendation from the Joint Chiefs of Staff. He approved both Army and Air Force development programs on the 8th of November 1955.

  Admiral Arleigh Burke, appointed Chief of Naval Operations in August 1955, bypassed his own service's skeptics and approached the Army directly. He found Jupiter's proposed range matched what the Navy needed for launches from safe areas in the Atlantic Ocean. A Killian Committee report published in September 1955 had formally endorsed a sea-based missile program. The Navy joined the Jupiter effort, tasked with developing systems to launch the missile from ships and submarines. That partnership transformed Jupiter's shape. The original Army design was 92 feet long and 95 inches in diameter. The Navy refused anything taller than 50 feet. Both sides eventually settled on a 58-foot design widened to 105 inches in diameter. That larger body barred Jupiter from any contemporary cargo aircraft, meaning every missile would have to travel to its base by ship or road.

  Project Nobska, a scientific workshop convened in the summer of 1956, ended the Navy's participation. Physicist Edward Teller told participants that by 1963 a one-megaton warhead could weigh as little as 600 pounds. Engineers at the meeting estimated that a solid-fuel missile carrying such a warhead might weigh around 30,000 pounds. Jupiter, burning liquid propellants, was expected to weigh 160,000 pounds. The Navy withdrew from the program in December 1956, and the Army announced the separation in January 1957. The Navy began work on what would become Polaris. Hyman Rickover, once one of the program's loudest skeptics, was won over after being told the mission required a purpose-built submarine and that he was the man to design it. The Air Force inherited Jupiter reluctantly. A memorandum from Secretary Wilson in November 1956 had limited the Army to weapons with a maximum range of 200 miles, and Jupiter exceeded that ceiling. An ARPA review conducted after the Soviet Sputnik launch in October 1957 confirmed that Jupiter was technically excellent, and new orders brought the total planned production to 94 missiles.

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• 3. Testing at Cape Canaveral

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  Karl Heimburg had begun construction of a static test stand at Redstone Arsenal in 1954, originally for Redstone testing, and the facility was not finished until January 1957. A Jupiter was installed and fired there for the first time on the 12th of February 1957. The test nearly ended in catastrophe. A small explosion in the liquid oxygen pump left the missile on the stand with its oxygen boiling off and threatening to burst the tanks. The foreman, Paul Kennedy, ran to the missile and manually connected a pressure line to drain the oxygen before it could rupture. Engineers traced the problem to the pump lubricant, which ignited in contact with liquid oxygen. A new lubricant and modifications to the test stand were introduced before static testing could continue.

  Kurt Debus had led the construction of two launch complexes at Cape Canaveral, LC-5 and LC-6, about 500 feet apart, with a shared blockhouse roughly 300 feet away. The initial flight failure was traced to turbopump exhaust being drawn into the vacuum behind the ascending missile, burning through control wiring. Extra insulation was added to subsequent vehicles. A second missile, AM-1B, launched on the 26th of April and flew normally until seventy seconds in. It then became unstable and broke apart at ninety-three seconds. Engineers determined that propellant sloshing had excited bending modes in the structure; steering corrections needed to hold the planned trajectory had made the instability worse. They fitted baffles inside the liquid oxygen and fuel tanks and prepared a third attempt.

  The third Jupiter flew on the 31st of May 1957, carrying the baffles and a slightly improved engine, and traveled 1,247 nautical miles downrange. Subsequent flights verified the ablative heat shield, the ST-90 inertial navigation system, and the separation of the rocket body from the reentry vehicle. Then two successive missiles, AM-3A and AM-4, lost thrust in flight when their turbopumps failed. The same pump design was used across the Jupiter, Thor, and Atlas programs, and the failures affected all three. Testing paused for five months while Rocketdyne redesigned the pumps. Despite these setbacks, Jupiter was declared operationally ready on the 15th of January 1958. The redesigned engine, now delivering its full design thrust, flew for the first time on the 18th of May 1958. A July flight designated AM-6B saw the Navy recover the nose cone just 1.5 nautical miles from its planned splashdown point, 1,241 miles downrange. The Army had once promised accuracy within half a mile at full range, a goal the Weapons Systems Evaluation Group had called hopelessly optimistic.

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• 4. Gordo, Able, and Baker

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  On the 13th of December 1958, a Jupiter launched from Cape Canaveral carrying a Navy-trained South American squirrel monkey named Gordo. Telemetry from the flight showed Gordo survived ten times the force of gravity at launch, eight minutes of weightlessness, and forty times gravity on reentry at a speed of 10,000 miles per hour. The nose cone was equipped with a recovery parachute. The parachute failed to open. The nose cone sank 1,302 nautical miles downrange, and Gordo did not survive.

  Jupiter AM-18 launched on the 28th of May 1959, carrying a seven-pound rhesus monkey named Able and an eleven-ounce squirrel monkey named Baker inside the nose cone. They reached an altitude of 300 miles and traveled 1,500 miles along the Atlantic Missile Range. Both endured accelerations of thirty-eight times gravity and about nine minutes of weightlessness. Their flight lasted sixteen minutes and reached a top speed of 10,000 miles per hour. The seagoing tug USS Kiowa recovered the nose cone after splashdown, and both monkeys were found in good condition.

  Able died four days after landing. The cause was not the flight itself but a reaction to anesthesia during surgery to remove an infected medical electrode. Baker outlived her companion by more than two decades. The small squirrel monkey lived at the United States Space and Rocket Center in Huntsville, Alabama, and died there on the 29th of November 1984 from kidney failure. One more biological nose cone flew on AM-23, on the 15th of September 1959, carrying mice and other specimens. A nitrogen pressure leak caused the missile to lose control at liftoff; the vehicle broke apart just thirteen seconds after launch, moments before the range safety officer could issue a flight termination command.

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• 5. Italy, Turkey, and Cuba

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  In April 1958, the Department of Defense notified the Air Force that three Jupiter squadrons totaling 45 missiles were tentatively planned for deployment in France. Two months later, France's new president, Charles de Gaulle, refused to accept them. The United States turned its attention to Italy and Turkey. In April 1959, the secretary of the Air Force issued instructions to deploy two squadrons in Italy. By 1961, thirty missiles had been installed at ten sites in the region around Gioia del Colle Air Base, which served as headquarters under the 36th Strategic Air Interdiction Brigade. Italian Air Force crews operated the missiles, but American personnel retained control of arming the nuclear warheads.

  A government-to-government agreement with Turkey was signed in October 1959. Fifteen missiles were deployed at five sites near Izmir, operated initially by American personnel. The first three were formally transferred to the Turkish Air Force in late October 1962. By then the missiles were widely considered obsolete. Fixed emplacements left them exposed to Soviet attack. Army General Maxwell Taylor argued that the Air Force's November 1958 decision to use fixed sites rather than mobile launchers was deliberate, intended to make the missiles look unsuitable for battlefield use and prevent their return to Army control. To compensate for the vulnerability, the launch sequence was shortened so a missile could be away within fifteen minutes of receiving an order.

  Between mid-October 1961 and August 1962, lightning struck Jupiter missiles at their Italian bases on four separate occasions. Each time, thermal batteries were activated. On two of those occasions, tritium-deuterium boost gas was injected into the warhead pits, partially arming the weapons. After the fourth lightning strike, the Air Force installed protective diversion towers at all Italian and Turkish Jupiter sites. In 1962, a Bulgarian MiG-17 reconnaissance plane reportedly crashed into an olive grove near one of the Italian launch sites after overflying it.

  A secret understanding reached during the Cuban missile crisis sealed the program's end. The Soviet Union had placed ballistic missiles in Cuba, and American demands for their removal brought the two countries to the edge of open conflict. As part of a quiet arrangement between the governments, the United States agreed to remove the Jupiter missiles from Turkey. All Jupiter missiles in Italy and Turkey were out of service by April 1963.

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• 6. Jupiter's Orbital Legacy

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  The Saturn I rocket's first stage was built using tooling developed for the Jupiter and Redstone programs. Engineers arranged a central tank of Jupiter diameter around eight outer tanks of Redstone diameter, all burning the same propellant combination. That cluster formed the first stage of both the Saturn I and the Saturn IB.

  Jupiter also flew in a modified form as the Juno II space launch vehicle. Adding clusters of Sergeant-derived solid-fuel upper stages transformed the Jupiter first stage into a four-stage rocket capable of reaching orbit. Juno II flew ten times between the 6th of December 1958 and the 24th of May 1961. Six of those launches failed. The successful missions placed Explorer 7, Explorer 8, Explorer 11, and Pioneer 4 on their intended trajectories. Pioneer 4, launched in March 1959, was the first successful American lunar probe.

  A Jupiter named Columbia was presented to the city of Columbia, South Carolina in the early 1960s and installed at the state fairgrounds in 1969 at a cost of ten thousand dollars. Other surviving examples stand in the rocket gardens at Kennedy Space Center in Florida, the Marshall Space Flight Center in Huntsville, and the National Museum of the United States Air Force in Dayton, Ohio. One missile removed from Cape Canaveral's display in 2009 for a full restoration was returned to storage in Hangar R on Cape Canaveral Air Force Station, where it remains today and is not open to the public.

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