Encyclopedia Astronautica
R-4D



r4d.jpg
R-4D
Credit: Aerojet Redmond
Marquardt N2O4/MMH rocket engine. 0.490 kN. Isp=312s. Developed as attitude control thruster for the Apollo Service and Lunar Modules in 1960s. In production for numerous satellites for apogee / perigee maneuvers, orbit adjustment, and attitude control.

Developed as an attitude control thruster for the Apollo's Service and Lunar Module. Each unit for the modules employed four quadruple clusters. Approximately 800 were built. The thruster is currently employed in the R-4D-10 version of the U.S. Navy's Leasat, R-4D-11 by Insat 1 and Arabasat 1, R-4D-12 by HS-393, Milstar, Intelsat 6, Italsat, and Olympus and Eurostar.. Manufacturer: Kasier Marquardt. Application: apogee/perigee maneuvers, orbit adjust, and attitude control. First Flown: February 1966 (Apollo 201). Number Produced: about 800. Dry Mass: 3.63 kg. Length: 55.41 cm. Maximum Diameter: 27.94 cm. Mounting: fixed. Engine Cycle: pressure-fed. Propellants: hypergolic nitrogen tetroxide and MMH or hyrdazine which was pressure-fed at 0.05 kg/sec fuel and 0.091 kg/sec oxidizer at atm. Mixture Ratio: 1.65 (1.0 - 2.4 range). Thrust: 490 N vacuum standard. Isp: 312 sec vacuum standard. Expansion Ratio: 164:1. Chamber Pressure: 6.84 atm. Combustion Chamber: a single chamber/nozzle of welded coated columbium (niobium), radiatively and film-cooled, controlled by an on/off solenoid, and a multiple doublet injector with hypergolic ignition.. Burn Time: up to 1 hour continuous with a 2.67 Ns min impulse bit.Used in Jarvis-3; IABS.

Application: Apollo LM, Leasat, Insat, HS 393, Milstar, Intelsat 6, Italsat, Eurostar.

Characteristics

Engine: 3.63 kg (8.00 lb). Chamber Pressure: 6.93 bar. Area Ratio: 164. Thrust to Weight Ratio: 13.7366869592086. Oxidizer to Fuel Ratio: 1.65. Coefficient of Thrust vacuum: 1.88806724749259.

Status: Study 1985.
Unfuelled mass: 3.63 kg (8.00 lb).
Height: 0.55 m (1.82 ft).
Diameter: 0.28 m (0.92 ft).
Thrust: 490 N (110 lbf).
Specific impulse: 312 s.
Number: 20 .

More... - Chronology...


Associated Countries
Associated Spacecraft
  • HS 381 American military communications satellite. 4 launches, 1984.08.30 (Syncom IV-2) to 1985.08.27 (Syncom IV-4). The Leasat HS 381 series was developed as a commercial venture to provide dedicated communications services to the U. S. military. More...
  • HS 393 American communications satellite. 7 launches, 1989.03.06 (JCSAT 1) to 1991.10.29 (Intelsat 6A F-1). Domestic communication. Launching states: Japan, France, USA. At the time, these were the largest commercial spacecraft ever built. More...
  • HS 601 American communications satellite bus. First launch 1990.01.09. 3-axis unified ARC 22 N and one Marquardt 490 N bipropellant thrusters, Sun and Barnes Earth sensors and two 61 Nms 2-axis gimbaled momentum bias wheels. More...

See also
Associated Launch Vehicles
  • Jarvis American orbital launch vehicle. Launch vehicle planned for Pacific launch based on Saturn V engines, tooling. Masses, payload estimated. More...
  • Atlas II American orbital launch vehicle. The Atlas II booster was 2.7-meters longer than an Atlas I and included uprated Rocketdyne MA-5A engines. The Atlas I vernier engines were replaced with a hydrazine roll control system. The Centaur stage was stretched 0.9-meters compared to the Centaur I stage. Fixed foam insulation replaced Atlas I's jettisonable insulation panels. The original Atlas II model was developed to support the United States Air Force Medium Launch Vehicle II program. Its Centaur used RL10A-3-3A engines operating at an increased mixture ratio. The first Atlas II flew on 7 December 1991, successfully delivering AC-102/Eutelsat II F3 to orbit. More...

Associated Manufacturers and Agencies
Associated Propellants
  • N2O4/MMH Nitrogen tetroxide became the storable liquid propellant of choice from the late 1950's. Monomethylhydrazine (CH3NHNH2) is a storable liquid fuel that found favour in the United States for use in orbital spacecraft engines. Its advantages in comparison to UDMH are higher density and slightly higher performance. More...

Associated Stages
  • IABS N2O4/MMH propellant rocket stage. Loaded/empty mass 1,578/275 kg. Thrust 0.98 kN. Vacuum specific impulse 312 seconds. More...
  • Jarvis-3 N2O4/MMH propellant rocket stage. Loaded/empty mass 13,400/2,000 kg. Thrust 3.92 kN. Vacuum specific impulse 312 seconds. More...

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