KING OF GODS: The Jupiter Missile Story
Seventh in a Series Reviewing Jupiter's Place in Space
by Ed Kyle, Updated 8/07/2011
Junos III, IV, and V and
Juno IVB Illustration - Three Stage Liquid Rocket
would have Stood about 35 Meters
In November 1957 JPL proposed "Juno III", a
four stage Jupiter-boosted rocket similar to Juno II but using more powerful upper stage
solid motors from Grand Central Rocket Company. Juno III would be able to lift about
54.4 kg (120 lbs) to low earth orbit (LEO), about 20% more than Juno II. Juno III
was proposed to launch a spacecraft to photograph the far side of the Moon.
ABMA and JPL planners knew that even more capable launch
vehicles would be needed. On March 20, 1958,
ABMA's General Medaris asked JPL to investigate the use of one or two liquid storable
propellant upper stages atop Jupiter. The new configuration would be named
On March 27, 1958, newly-formed Advanced Projects
Research Agency (ARPA) announced "Operation Mona", its program to aim U.S.
satellites toward the Moon. ARPA funded three Thor-Able and two Juno II launches for
the program. Juno III was not included, which effectively ended all plans for Juno
By early April, JPL had completed a preliminary design
study for Juno IV and briefed ABMA on the results. Its
study recommended use of hypergolic pressure-fed liquid upper stages. Juno IV would be capable of lifting up to 10 to 20
times as much payload as Juno II/III,
Juno IVs upper stages would use nitrogen tetroxide (N2O4) oxidizer and hydrazine
(N2H4) fuel. JPL would develop two new engines
for the stages. A 20.4 tonne force (45,000 lb)
thrust engine would power the second stage. A
2.72 tonne force (6,000 lb) thrust engine would propel the third stage.
Both stages would be pressure-fed, using helium stored
in high-pressure spheres. A heated
hybrid pressure feeding system was proposed for both stages. The system would use a small hydrazine gas
generator to heat helium passing through a heat exchanger.
Gas generator products would pressurize the hydrazine tank. Heated helium would pressurize the nitrogen
tetroxide tank. The heated hybrid
approach would result in substantially lower mass compared to standard pressure fed
The main engines would gimbal for pitch and yaw control. Gimbaled gas generator exhaust would provide roll
control. The third stage would have used
hydrazine thrusters for three-axis control during coasting periods.
Both stages were limited to 1.778 meters (70 inches) in
diameter to allow mating atop the existing Jupiter guidance compartment (aft
unit). The stages would consist of
separate 2014-T6 aluminum fuel and oxidizer tanks supported by aluminum semi-monocoque
interstage and intertank structures. Oxidizer
would be stored in the forward tank, fuel in the aft tank, on both stages.
A three-stage Juno IV would weigh up to 62.41 tonnes
(137,600 lbs) at liftoff. Its Jupiter first
stage would be loaded with up to 44.5 tonnes (98,100 lbs) of propellant. The second stage would carry up to 11.14 tonnes
(24,550 lbs) of propellant. The third stage
would be loaded with up to 3.4 tonnes (7,500 lbs) of propellant. Propellant loading would vary depending on the
mission type, with maximum upper stage loading for LEO missions and reduced loading for
lunar or escape missions. Reduced upper stage
propellant loads would be offset by increased first stage propellant loads, and
Projected Appearance of Juno IVA and Juno IVB
Three-stage Juno IV would be able to lift 1,000 kg
(2,200 lbs) to a 400 km (250 mile) orbit, or 163 kg (360 lbs) toward the Moon. This was more than three times better than
Thor-Able and comparable to Thor-Agena A, an IRBM-based launcher then under development
that would have been a Juno IV contemporary. Pickering
asked his JPL teams to study a 159 kg (350 pound) Mars flyby spacecraft that Juno IV could
On May 1, 1958,ARPA gained control of Juno I and II,
beginning the transition of orbital launch programs away from the U.S.
Army. ABMA and JPL formally proposed Juno IV development to ARPA on May 5. The proposal called for a first flight in March
1959 using an interim second stage engine, a 15 tonne (33,000 lb) thrust GE 405H model
derived from Vanguards first stage engine, as an interim step while JPLs new
45K engine was developed.
ARPA authorized JPL to continue its Juno IV upper stage design work on May
31, 1958. The Lab test fired a 45K
development engine on June 3. This was only a
brief firing using an uncooled nozzle. JPL
performed similar tests of its 6K engine.
Testing showed that the second stage engine would achieve 304 second vacuum
specific impulse while the third stage engine would make 301 seconds.
During July, two ARPA engineers, David A. Young and
Richard B. Canright, visited ABMA to review programs.
While there, they learned about a year-old ABMA study for a Super
Jupiter. Super Jupiter plans
called for a first stage of unprecedented size powered by four yet-to-be-developed
Rocketdyne E-1 engines that together would have produced 671 tonnes (1.48 million pounds)
of thrust. ARPAs engineers were
interested in moving quickly during that post-Sputnik era.
They suggested substituting eight existing Thor/Jupiter S-3D engines for the
still-to-be-developed E-1. The change would save $60 million and two years in development
time. The new rocket was soon named Juno
Juno IV Authorized
Juno IV went through a series of proposal stages during the summer of
1958. Plans to use the GE engine were dropped
in favor of an interim Juno IVA two-stage rocket. Juno IVA would use the third stage as a second
stage, with the stage slightly enlarged to carry up to 4.08 tonnes (9,000 lbs) of
propellant. Juno IVA would lift about 494 kg
(1,090 lbs) to a 400 km (250 mile) orbit, but would be unable to perform lunar or escape
JPL would employ a light weight guidance system, borrowed from the
Sergeant missile program, for Juno IVA. The
Jupiter ST-90 platform would have operated during first stage flight. MING (Miniature Injection Guidance) would have
controlled the second stage flight. The system
would have used a single-axis platform for pitch guidance, augmented by miniature
integrating gyros for yaw and roll. A magnetic
tape recorder programmer would have provided pitch program control.
On August 15, 1958, ARPA authorized development of both Juno IVA and Juno
V. Plans called for at least three Juno IVA
launches, beginning in 1959. ARPA expanded the
program in September, adding three three-stage flights.
The GE engine reentered the program to power the second stage on these flights. The three-stage rockets would be named Juno
IVB. Plans still called for eventual use
of JPLs 45K engine.
Sudden Death, and Vega
Atlas-Vega would have
used Juno IV Upper Stage
NASA official began operations on October 1, 1958 and began picking up the
ARPA programs. On October 9, NASAs Propulsion Committee met with ARPA
officials. During the meeting, NASAs Dr.
Abe Silverstein said that NASA would keep ARPAs Juno II program, but would drop Juno
IV. Juno IV, he said, would do no job
that the old boosters that are around now cannot do.
On October 10, ABMAs Lt. Col Glenn Crane met with Silverstein who again
reaffirmed his Juno IV decision.
Reflecting NASAs plans, ARPA officially canceled Juno IV on October
17, 1958. About $8 million of Juno IV funding was redirected to Juno V. Suddenly
Jupiter was a dead end program, with only a limited missile deployment and only 10 Juno II
orbital launches planned. With the first Juno II launch still two months away, the
Juno II project team found itself working on a project with an expiration date.
All four of the original IRBM/ICBM U.S. missile programs led to orbital
launch vehicles, but Silversteins abrupt October 1958 decision determined that
Jupiters family would have a short and bittersweet life.
The Juno IV decision spelled the beginning of the end of JPLs
in-house launch vehicle propulsion work. JPL joined NASA on December 3, 1958. Three days later the new NASA center proposed its
6K Juno IV upper stage for use with NASA proposed Atlas-Vega launch vehicles. On January 30, 1959, JPL was awarded $2 million to
start work on the engine.
On March 17, 1959, JPL performed its first fuel-cooled 6K
engine test. Plans called for eight Atlas-Vega
launches beginning in August 1960. Before the
year ended, however, NASA learned about the secret Agena B program. Like JPLs 6K stage, Agena B would
be restartable. On September 30, a
recommendation was made to drop the JPL stage in favor of Agena B. Silverstein made the decision official in early
November, and the entire Vega program was canceled on December 7, 1959.
JPLs upper stage work ended. The
Lab was left with NASAs exploration spacecraft work, at which it soon excelled. Early studies of Juno IV launched spacecraft for
exploring the Moon and Mars led to the eventual development of Ranger and Mariner.
Mercury-Jupiter Projected Appearance, Illustrating Mating Problem
Early NASA plans for Project Mercury, as of late 1958, were to use eight
Mercury Redstones augmented by two Mercury Jupiters for suborbital test flights. The
Mercury Jupiters would have explored the flight envelope at higher velocities than
Redstone, prior to the use of Mercury-Atlas.
The first flight would have carried a primate, the second possibly an
astronaut. Later plans hinted at unmanned tests only, with the flights meant to
qualify Mercury for maximum reentry load factors. ABMA would have built the
spacecraft adapter for Jupiter.
In July 1959, NASA canceled Mercury-Jupiter when it
became apparent that Atlas could serve the same purpose. Basically the schedule was
so compressed that Atlas flights would have happened before the Jupiter flights.
NASA spent $1.8 million on Mercury-Jupiter before canceling the effort. Although two
Jupiters were ordered, they do not appear to have ever been delivered.
One challenge was that the Mercury spacecraft and escape
tower weighed 1.935 tonnes, about 0.75 tonnes more than Jupiters nose cone. In addition, Jupiters aft unit
guidance and control compartment could be cut down to only 1.778 meters (70 inches) in
diameter at its top while the Mercury capsule was 1.892 meters (74.5 inches) in diameter. NASA eventually deemed the structural redesign
effort excessive for only two flights.
Saturn I (SA-T) Assembly Showing Jupiter and
Although it lost Juno IV, ABMA was kept very busy with
Juno V. ABMA decided to use not just a cluster
of engines, but also a cluster of tanks. The
design combined eight 1.778 meter (70-inch) diameter tanks, built using Redstone tooling,
with a central 2.667 meter (105-inch) diameter tank manufactured with Jupiter missile
tooling. The central tank and four of the outer tanks would carry LOX and would be load
bearing. The other four tanks would carry kerosene fuel and would not carry structural
loads because they would not expand and contract as much as the supercold LOX tanks.
In August 1958, ARPA initially provided funding for a
Juno V feasibility demonstration project The
original plan called for construction of only one booster for captive firing tests on a
modified Jupiter/Redstone test stand at the Arsenal. ABMA quickly contracted Rocketdyne to
develop the first stage engine, now designated H-1. Early H-1 versions would be rated at
165,000 pounds thrust. Later models would produce 188,000 pounds of thrust.
Years after the final Juno II launch, after the deployed
Jupiter missiles were scrapped or turned into lawn ornaments, and after the old
Jupiter/Redstone launch complex had been turned into a museum, Jupiters legacy lived
on in NASAs Saturn and Saturn IB. Chrysler
assembled Jupiter based tanks for Saturn until production ended in 1968. The final Saturn IB launch, for the ASTP mission,
took place on July 15, 1975, about 20 years after Wernher von Braun had presented
ABMAs IRBM proposal to the Armed Services Policy Committee.
Juno IV Rocket Vehicle System, JPL Report No. 20-123,
December 27, 1960.
Project Ranger - A Chronology, R. Cargill Hall, JPL,
Juno V Space Vehicle Development Program Status Report,
H.H. Koelle, ABMA, November 15, 1958.
Images ABMA/USAF with thanks to Art LeBron