 Apollo LM ascent engine | |
| Country of origin | United States |
|---|---|
| Date | 1964–72 |
| Manufacturer | Bell Aircraft /Rocketdyne |
| Application | Lunar Ascent Stage/Spacecraft propulsion |
| Predecessor | Bell 8247 |
| Successor | RS-18 |
| Status | Retired |
| Liquid-fuel engine | |
| Propellant | N 2O 4 /Aerozine 50 |
| Mixture ratio | 1.6 |
| Cycle | Pressure-fed |
| Pumps | None |
| Configuration | |
| Chamber | 1 |
| Nozzle ratio | 46 |
| Performance | |
| Thrust, vacuum | 3,500 pounds-force (16 kN) |
| Thrust-to-weight ratio | 16.7 (weight on Earth) |
| Chamberpressure | 120 pounds per square inch (8.3 bar) |
| Specific impulse, vacuum | 311 seconds (3.05 km/s) |
| Burn time | 200 seconds |
| Restarts | Designed for 1 restarts |
| Dimensions | |
| Length | 510 inches (1,300 cm) |
| Diameter | 100 inches (250 cm) |
| Dry mass | 209.6 pounds (95.1 kg) |
| Used in | |
| Lunar module as ascent engine | |
| References | |
| References | [1] |
Theascent propulsion system (APS) orlunar module ascent engine (LMAE) is a fixed-thrusthypergolicrocket engine developed byBell Aerosystems for use in theApollo Lunar Module ascent stage. It usedAerozine 50 fuel, andN
2O
4 oxidizer.Rocketdyne provided the injector system, at the request of NASA, when Bell could not solve combustion instability problems.[2]
The LMAE traces its origin to the earlier Bell Aerosystems engines (8096, 8247) used in theRM-81 Agena, the rocket upper stage and satellite support bus developed byLockheed initially for the canceled WS-117Lreconnaissance satellite program.[3]The Agena served as an upper stage for several defense, intelligence, and exploration programs:SAMOS-E,SAMOS-F (ELINT Ferret) andMIDAS (Missile Defense Alarm System) military early-warning satellites,Corona photo intelligence program, and theRanger andLunar Orbiter lunar probes.
The LockheedAgena target vehicle using the Bell 8247 engine was qualified for 15 restarts for NASA'sProject Gemini.[4]
A total of 365 Agena rockets were launched by NASA and the U.S. Air Force between February 28, 1959, and the last Agena D launched on 12 February 1987, configured as the upper stage of aTitan 34B.[5][6]
During the spring of 1963, Grumman hired Bell to develop the lunar module ascent engine, on the assumption that Bell's experience in development of the Air Force Agena engine would be transferable to the lunar module requirements. Grumman placed heavy emphasis upon high reliability through simplicity of design, and the ascent engine emerged as the least complicated of the three main engines in the Apollo space vehicle, including the LM descent andCSM service propulsion system engines.
Embodying a pressure-fed fuel system using hypergolic (self-igniting) propellants, the ascent engine was fixed-thrust and nongimbaled, capable of lifting the ascent stage off the Moon or aborting a landing if necessary.[7]
The engine developed about 1,600 pounds-force (7.1 kN) of thrust, which produced a velocity of 3,200 meters per second from lunar launch, to LOR, and CM docking.[7][2]
Rocketdyne brought the lunar module ascent engine out of its 36-year retirement in 2008 for NASA'sExploration Systems Architecture Study (ESAS) engine testing, re-designated it asRS-18, and reconfigured the non-throttleablehypergolic engine to use LOX/methane.[8]
This article incorporatespublic domain material from websites or documents of theNational Aeronautics and Space Administration.
| Launch vehicles | |
|---|---|
| Launch vehicle components | |
| Spacecraft | |
| Spacecraft components | |
| Space suits | |
| Lunar surface equipment |
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| Ground support | |
| Ceremonial | |
| Related | |
Spacecraft engines and motors | ||
|---|---|---|
| Liquid fuel engines |  | |
| Solid propellant motors | ||
| Related articles | ||
