Encyclopedia Astronautica
J-2



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J-2
Credit: © Mark Wade
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J-2
Credit: Boeing / Rocketdyne
Rocketdyne lox/lh2 rocket engine. 1033.1 kN. Study 1961. Isp=421s. Used in Saturn IVB stage in Saturn IB and Saturn V, and Saturn II stage in Saturn V. Gas generator, pump-fed. First flight 1966.

Specific impulse and thrust is for final flight version; J-2 had a specific impulse of 418 sec/thrust of 90,700 kgf/mix ratio of 5.00 on LV's SA-201 through 203, and 419 sec/thrust of 102,040 kgf on SA-204 through 207 and SA-501 to 503. Sea level versions with reduced expansion ratio proposed for Saturn II first stage use. Upgraded toroidal aerospike versions (J-2T-200K and J-2T-250K) studies for upgrades to Saturn upper stages. Modestly improved J-2S was tested and provides basis for X-33 linear aerospike engine thirty years later. Proposed for use in Nova A-2; Saturn IVB; Nova NASA-3; Nova B-2; Saturn II; Jarvis-2; Saturn MS-II-1; Saturn S-II-8; Saturn S-IVC; Nova 60-8-3; Saturn S-II-C3; Saturn S-II-4; Saturn S-II. Saturn V S-ll & S-IVB Stage Engines, Saturn IB S-IVB. Upper Stage Engine.

Thrust (sl): 486.200 kN (109,302 lbf). Thrust (sl): 49,577 kgf. Engine: 1,438 kg (3,170 lb). Chamber Pressure: 30.00 bar. Area Ratio: 28. Thrust to Weight Ratio: 73.1801112656467. Oxidizer to Fuel Ratio: 5.5. Coefficient of Thrust vacuum: 3.35409543547025. Coefficient of Thrust sea level: 2.42076210213692.

Status: Study 1961.
Unfuelled mass: 1,438 kg (3,170 lb).
Height: 3.38 m (11.08 ft).
Diameter: 2.01 m (6.60 ft).
Thrust: 1,033.10 kN (232,250 lbf).
Specific impulse: 421 s.
Specific impulse sea level: 200 s.
Burn time: 475 s.
First Launch: 1960.
Number: 87 .

More... - Chronology...


Associated Countries
Associated Spacecraft
  • NASA Mars Flyby 1965 American manned Mars flyby. Study 1965. Mars flyby mission designed by NASA Huntsville in 1965 to use existing Apollo hardware, allowing a manned flyby of Mars by 1975. More...
  • Saturn MS-IVB-x American space tug. Study 1965. Upper stage / space tug - studied by NASA Marshall in 1965. Launched by Saturn V. S-IVB structurally strengthened to handle larger payloads, otherwise unchanged More...
  • Saturn MS-IVB-4(S)B American space tug. Study 1967. Upper stage / space tug - studied by Boeing in 1967. Standard S-IVB but with structural strength increased from 78% to 217% depending on station, resulting in 11.8% increase in empty weight. More...

See also
Associated Launch Vehicles
  • Saturn C-2 American orbital launch vehicle. The launch vehicle initially considered for realizing the Apollo lunar landing at the earliest possible date. 15 launches and rendezvous required to assemble direct landing spacecraft in earth orbit. More...
  • Nova NASA American heavy-lift orbital launch vehicle. The Nova vehicle most often illustrated in the popular press and histories. As in other early concepts, this NASA design of 1959/1960 used F-1 engine in both first and second stages. Resulting performance and total liftoff mass was equivalent to later Saturn V. More...
  • Nova B American heavy-lift orbital launch vehicle. Convair/Ehricke Nova design using standard tank/engine modules of 4.9 m diameter in both first and second stages; 6 F-1 engine/modules in first stage, 6 J-2 engine/modules in second stage. More...
  • Nova C American nuclear orbital launch vehicle. General Dynamics Nova vehicle using Nova A as first two stages, nuclear spacecraft with jettisonable tanks as upper stage. More...
  • Nova 8L Mod American heavy-lift orbital launch vehicle. NASA Nova concept where first two stages use short Nova building blocks with 2 F-1's in each block. Four used in stage 1, one in stage 2. Typical of early Nova designs with F-1's in both first and second stages. More...
  • Nova D American nuclear orbital launch vehicle. General Dynamics Nova vehicle using Nova B as first two stages, nuclear spacecraft with jettisonable tanks as upper stage. More...
  • Nova 9L American heavy-lift orbital launch vehicle. NASA Nova design using clustered small diameter tanks; 9 x F-1 first stage and 4 x F-1 second stage; compared with solid Nova using five six segment solid motors in first stage and four four segment motors in second stage. More...
  • Nova 7S American heavy-lift orbital launch vehicle. NASA Nova design using a cluster of 7 x 160 inch solid motors used as first stage; upper stages as Nova 4S and 8L. More...
  • Nova 5S American heavy-lift orbital launch vehicle. NASA Nova design using segmented solid motors in first and second stages. Five six segment motors in first stage; four four segment motors in second stage, equivalent to 9 x F-1 first stage and 4 x F-1 second stage. More...
  • Nova 4S American heavy-lift orbital launch vehicle. NASA Nova design using a cluster of 4 x 240 inch solid motors used as first stage; upper stages as Nova 7S and 8L. More...
  • Saturn C-4 American orbital launch vehicle. The launch vehicle actually planned for the Lunar Orbit Rendezvous approach to lunar landing. The Saturn C-5 was selected instead to have reserve capacity. More...
  • Nova A American heavy-lift orbital launch vehicle. Convair/Ehricke Nova design using standard tank/engine modules of 4.9 m diameter in both first and second stages; 4 F-1 engine/modules in first stage, 4 J-2 engine/modules in second stage. More...
  • Saturn C-3 The launch vehicle concept considered for a time as the leading contender for the Earth Orbit Rendezvous approach to an American lunar landing. More...
  • Saturn C-5 American orbital launch vehicle. Final configuration of Saturn C-5 at the time of selection of this configuration for the Apollo program in December 1961. The actual Saturn V would be derived from this, but with an increased-diameter third stage (6.61 m vs 5.59 m in C-5) and increased propellant load in S-II second stage. More...
  • Saturn C-4B American orbital launch vehicle. Final configurtion of the Saturn C-4 at the time of selection of the Saturn C-5 configuration for the Apollo program in December 1961. Only Saturn configuration with common bulkhead propellant tanks in first stage, resulting in shorter vehicle than less powerful Saturn C-3. More...
  • Saturn C-3B American orbital launch vehicle. Final configurtion of the Saturn C-3 at the time of selection of the Saturn C-5 configuration for the Apollo program in December 1961. More...
  • Saturn C-5N American nuclear orbital launch vehicle. Version of Saturn C-5 considered with small nuclear thermal stage in place of S-IVB oxygen/hydrogen stage. More...
  • Saturn C-3BN American nuclear orbital launch vehicle. Version of Saturn C-3 considered with small nuclear thermal stage in place of S-IVB oxygen/hydrogen stage. More...
  • Nova 8L American heavy-lift orbital launch vehicle. Most capable NASA Nova design, studied in June 1960 just prior to selection of Saturn for moon landing. Used a three stage configuration of eight F-1 engines in stage 1, two M-1 engines in stage 2, and one J-2 engine in stage 3. Similar to the Saturn C-8 except in the use of M-1 engines. Unlike other modular Nova designs of the time, this one had the unitary stage construction of Saturn. More...
  • Saturn C-8 American orbital launch vehicle. The largest member of the Saturn family ever contemplated. Designed for direct landing of Apollo command module on moon. Configuration used eight F-1 engines in the first stage, eight J-2 engines in the second stage, and one J-2 engine in the third stage. Distinguishable from Nova 8L in use of J-2 engines instead of M-1 engines in second stage. More...
  • Nova GD-B American heavy-lift orbital launch vehicle. General Dynamics Nova design using existing engines. Recoverable engine package; separation at 3,398 m/s at 76,200 m altitude; splashdown using retrorockets under 7 30 m diameter parachutes 1300 km downrange. Massed estimated based on tank volumes, total thrust, and first stage burnout conditions. More...
  • Saturn IB-A American orbital launch vehicle. Douglas Studies, 1965: S-IB with 225 k lbf H-1's; S-IVB stretched with 350,000 lbs propellants; Centaur third stage. More...
  • Saturn IB American orbital launch vehicle. Improved Saturn I, with uprated first stage and Saturn IVB second stage (common with Saturn V) replacing Saturn IV. Used for earth orbit flight tests of Apollo CSM and LM. More...
  • Jarvis American orbital launch vehicle. Launch vehicle planned for Pacific launch based on Saturn V engines, tooling. Masses, payload estimated. More...

Associated Manufacturers and Agencies
Associated Propellants
  • Lox/LH2 Liquid oxygen was the earliest, cheapest, safest, and eventually the preferred oxidiser for large space launchers. Its main drawback is that it is moderately cryogenic, and therefore not suitable for military uses where storage of the fuelled missile and quick launch are required. Liquid hydrogen was identified by all the leading rocket visionaries as the theoretically ideal rocket fuel. It had big drawbacks, however - it was highly cryogenic, and it had a very low density, making for large tanks. The United States mastered hydrogen technology for the highly classified Lockheed CL-400 Suntan reconnaissance aircraft in the mid-1950's. The technology was transferred to the Centaur rocket stage program, and by the mid-1960's the United States was flying the Centaur and Saturn upper stages using the fuel. It was adopted for the core of the space shuttle, and Centaur stages still fly today. More...

Bibliography
  • Kudryavtseva, V M, ed., Zhidkostnikh Raketnikh Dvigatley, Visshaya Shkola, Moscow, 1993.

Associated Stages
  • Astro-2 Lox/LH2 propellant rocket stage. Loaded/empty mass 89,290/14,000 kg. Thrust 1,170.00 kN. Vacuum specific impulse 425 seconds. Engines 2 x RL-10 plus 1 x J-2 More...
  • Jarvis-2 Lox/LH2 propellant rocket stage. Loaded/empty mass 145,000/15,000 kg. Thrust 1,031.98 kN. Vacuum specific impulse 425 seconds. More...
  • Nova GD-B-2 Lox/LH2 propellant rocket stage. Loaded/empty mass 998,000/75,000 kg. Thrust 10,669.00 kN. Vacuum specific impulse 428 seconds. Massed estimated based on tank volumes, total thrust, and first stage burnout conditions. More...
  • Nova NASA-3 Lox/LH2 propellant rocket stage. Loaded/empty mass 227,000/21,000 kg. Thrust 2,667.00 kN. Vacuum specific impulse 420 seconds. More...
  • Nova B-2 Lox/LH2 propellant rocket stage. Loaded/empty mass 614,000/38,000 kg. Thrust 10,228.00 kN. Vacuum specific impulse 420 seconds. More...
  • Nova A-2 Lox/LH2 propellant rocket stage. Loaded/empty mass 403,000/29,000 kg. Thrust 5,334.00 kN. Vacuum specific impulse 420 seconds. More...
  • Nova 9L-4 Lox/LH2 propellant rocket stage. Loaded/empty mass 118,000/14,000 kg. Thrust 1,775.00 kN. Vacuum specific impulse 420 seconds. Masses estimated based on total vehicle thrust, performance, and stage volumes. More...
  • Nova 9L-3 Lox/LH2 propellant rocket stage. Loaded/empty mass 363,000/36,000 kg. Thrust 5,334.00 kN. Vacuum specific impulse 420 seconds. Masses estimated based on total vehicle thrust, performance, and stage volumes. More...
  • Nova 60-8-3 Lox/LH2 propellant rocket stage. Loaded/empty mass 227,000/23,000 kg. Thrust 892.00 kN. Vacuum specific impulse 425 seconds. Mass estimated based on total LV weight. More...
  • Nova 4 J-2 Lox/LH2 propellant rocket stage. Loaded/empty mass 771,000/63,000 kg. Thrust 3,559.00 kN. Vacuum specific impulse 420 seconds. Nova third stage. More...
  • Saturn MS-II-1A Lox/LH2 propellant rocket stage. Loaded/empty mass 600,800/60,000 kg. Thrust 6,380.94 kN. Vacuum specific impulse 421 seconds. Basic Saturn II with 187 inch stretch of propellant tanks, 1.2 million pound propellant capacity, and 7 J-2 engines. More...
  • Saturn S-II-8 Lox/LH2 propellant rocket stage. Loaded/empty mass 770,835/63,480 kg. Thrust 8,265.26 kN. Vacuum specific impulse 425 seconds. Version for Saturn C-8. More...
  • Saturn S-II-4 Lox/LH2 propellant rocket stage. Loaded/empty mass 294,731/24,938 kg. Thrust 3,557.31 kN. Vacuum specific impulse 420 seconds. Version for Saturn C-4. More...
  • Saturn S-II Lox/LH2 propellant rocket stage. Loaded/empty mass 100,000/14,000 kg. Thrust 3,557.31 kN. Vacuum specific impulse 420 seconds. Early design version for use with Saturn I first stage. More...
  • Saturn MS-IVB-x Lox/LH2 propellant rocket stage. Loaded/empty mass 195,000/36,300 kg. Thrust 912.00 kN. Vacuum specific impulse 421 seconds. Marshall studies, 1965: S-IVB structurally strengthened to handle larger payloads, otherwise unchanged More...
  • Saturn MS-IVB-4(S)B Lox/LH2 propellant rocket stage. Loaded/empty mass 118,400/14,100 kg. Thrust 1,031.60 kN. Vacuum specific impulse 421 seconds. Standard S-IVB but with structural strength increased from 78% to 217% depending on station, resulting in 11.8% increase in empty weight. More...
  • Saturn MS-IVB-1A Lox/LH2 propellant rocket stage. Loaded/empty mass 179,200/20,400 kg. Thrust 1,031.60 kN. Vacuum specific impulse 421 seconds. S-IVB with 16.5 foot stretch, 350,000 pounds propellant, standard J-2 engine. More...
  • Saturn S-IVC Lox/LH2 propellant rocket stage. Loaded/empty mass 204,044/22,671 kg. Thrust 1,031.98 kN. Vacuum specific impulse 425 seconds. More...
  • Saturn MS-II-4(S)B Lox/LH2 propellant rocket stage. Loaded/empty mass 494,100/42,300 kg. Thrust 5,169.00 kN. Vacuum specific impulse 421 seconds. Standard S-II but with structural strength increased from 86% to 502% depending on station, resulting in 8.6% increase in empty weight. More...
  • Saturn S-II-C3 Lox/LH2 propellant rocket stage. Loaded/empty mass 204,044/24,938 kg. Thrust 3,557.31 kN. Vacuum specific impulse 420 seconds. Version for Saturn C-3. More...
  • Saturn MS-IVB-1 Lox/LH2 propellant rocket stage. Loaded/empty mass 120,500/13,900 kg. Thrust 1,031.60 kN. Vacuum specific impulse 421 seconds. Marshall studies, 1965: S-IVB structurally strengthened to handle larger payloads, otherwise unchanged More...
  • Saturn IVB-A Lox/LH2 propellant rocket stage. Loaded/empty mass 118,800/12,900 kg. Thrust 956.10 kN. Vacuum specific impulse 421 seconds. Douglas Studies, 1965: S-IVB with 215k lbf J-1 (actual final model had 230k J-1) More...
  • Saturn IVB C-5A Lox/LH2 propellant rocket stage. Loaded/empty mass 102,249/11,563 kg. Thrust 889.33 kN. Vacuum specific impulse 420 seconds. Final common third stage design for Saturn C-4 and C-5 (November 1961). Developed into Saturn V second stage. After development started, decision taken to boost performance by increasing diameter to 6.61 m and increasing propellant load. More...
  • Saturn IVB C-3B Lox/LH2 propellant rocket stage. Loaded/empty mass 52,144/6,801 kg. Thrust 889.33 kN. Vacuum specific impulse 420 seconds. Final common third stage design for Saturn C-3B (November 1961). More...
  • Saturn IVB (S-V) Lox/LH2 propellant rocket stage. Loaded/empty mass 119,900/13,300 kg. Thrust 1,031.60 kN. Vacuum specific impulse 421 seconds. Saturn V version of S-IVB stage for use with upper stage. More...
  • Saturn IVB (S-IB) Lox/LH2 propellant rocket stage. Loaded/empty mass 118,800/12,900 kg. Thrust 1,031.60 kN. Vacuum specific impulse 421 seconds. Saturn IB version of S-IVB stage. Due to lower payload payload, 300 kg saving in structure compared to Saturn V version. Due to deletion of restart requirement, 700 kg saving in propulsion system (primarily reduction in helium for restart). More...
  • Saturn IVB Lox/LH2 propellant rocket stage. Loaded/empty mass 119,920/13,311 kg. Thrust 1,031.98 kN. Vacuum specific impulse 425 seconds. Configuration as flown on Saturn V. More...
  • Saturn II C-5A Lox/LH2 propellant rocket stage. Loaded/empty mass 384,057/31,740 kg. Thrust 4,446.65 kN. Vacuum specific impulse 420 seconds. Final common second stage design for Saturn C-3, C-4 and C-5 (November 1961). Developed into Saturn V second stage. More...
  • Saturn II Lox/LH2 propellant rocket stage. Loaded/empty mass 490,778/39,048 kg. Thrust 5,165.79 kN. Vacuum specific impulse 421 seconds. Configuration as flown. More...
  • Saturn MS-II-1 Lox/LH2 propellant rocket stage. Loaded/empty mass 521,447/49,877 kg. Thrust 5,165.79 kN. Vacuum specific impulse 425 seconds. Basic Saturn II with 41 inch stretch of hydrogen tank. More...
  • SLS Stage A Lox/LH2 propellant rocket stage. Loaded/empty mass 59,000/6,000 kg. Thrust 889.33 kN. Vacuum specific impulse 424 seconds. Smallest Lox/LH2 stage planned for SLS series. Empty mass estimated. Sized for rail transport within USA. More...
  • SLS Stage B Lox/LH2 propellant rocket stage. Loaded/empty mass 160,000/11,200 kg. Thrust 1,778.65 kN. Vacuum specific impulse 424 seconds. Tranlunar injection stage for Project Lunex. Masses estimated based on optimum apportioning of B+C stage total masses. More...

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