The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

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Jupiter A floodlit Jupiter C is prepared for launch from
Cape Canaveral. U.S. Army
Both Juno I and Jupiter C used a Redstone first stage
with stretched tanks to hold more fuel. But the Jupiter
C booster burned LOX and alcohol, like the production
version of the Redstone missile. The satellitecarrying
Juno I first stage was modified to burn
higher-energy Hydyne fuel. Both the C and Juno I
used clustered Baby Sergeant solid motors on their
second and third stages. However, since the C was
never meant to launch satellites, it had no fourthstage
motor. The Jupiter C first stage, with a liftoff
thrust of 348,000 N, burned for 150 seconds before
falling away. This was followed by a 6-second firing
from the second stage, separation and a 2-second
pause, and finally a 6-second burst from the third
stage. After this, the payload flew on its own, in a ballistic
arch, toward the ocean. The intense heat of reentry
enabled valuable scientific data to be gathered on
flight dynamics and nosecone performance.
The first Jupiter C was launched from Cape
Canaveral on September 20, 1956, and surpassed
expectations. This was the only C to carry an inert
fourth-stage ballasted with sand in case ABMA accidentally
launched a satellite before Project Vanguard.
The fourth stage soared 1,097 km high and 5,390 km
downrange, setting new Cape records—a bittersweet
success for ABMA. The Jupiter C had shown it was
perfectly capable of launching a small satellite, yet
bureaucracy forbade it to make the attempt.
Although 12 Jupiter Cs had been authorized for construction,
the research program was canceled after just
three launches in August 1957 by ABMA’s chief, Maj.
Gen. John Medaris. However, Medaris ordered that all
remaining C booster hardware be mothballed, his
intent being to keep the rocket components ready if the
green light came to attempt a satellite launch. With
Jupiter C performance data in hand, the Army continued
to seek a go-ahead to launch instrumented satellites
in support of the International Geophysical Year, but
without success. Then came the shocking news that the
Soviets had placed Sputnik 1 in orbit. By coincidence,
Secretary of Defense Neil McElroy was visiting the
Redstone Arsenal on that very day in October 1957.
ABMA top brass tried to persuade McElroy on the spot
that the Army deserved a chance to launch an American
reply. Medaris secretly told Wernher von Braun,
ABMA’s technical director, to start preparing Jupiter C
hardware for action, and the Army-sponsored JPL (Jet
Propulsion Laboratory) was asked to evaluate satellite
designs. McElroy did convince President Eisenhower
to look favorably on the Army’s request, but it was
almost two months after Sputnik 1’s triumph when
ABMA finally got approval to schedule satellite launch
dates. It was to be a major turning point in American
space history. The Navy’s Project Vanguard failed in its
first attempt to launch a small tracking satellite on
December 6, 1957, when the Vanguard rocket blew up
on its pad. Then the Navy’s second attempt, scheduled
for January 24, 1958, was delayed until early February.
Suddenly, ABMA’s first shot at orbit, originally slated
for five days after the Navy’s second attempt, was next
in line. But there would be one final twist before America
entered space. In November 1957, William Pickering,
head of JPL, suggested to Medaris that the
satellite-bearing version of the Jupiter C be renamed.
The recommendation was accepted by ABMA, and the
Juno family of rockets was born.