This model of thrust chamber was developed for the Apollo Lunar Module decent stage and made 10 flights during the Apollo program. The engine type became famous again in the 1995 with the release of the movie "Apollo 13" as the engine that powered the crippled Apollo 13 spacecraft from the moon back to earth because the Service Propulsion System was never used subsequent to the cryotank stir/explosion. Because the extent of damage to the SPS was unknown, there was great concern at the time that collateral damage could have caused a catastrophic malfunction (if the engine was fired). Instead the LMDE was used for the return burn and subsequent course correction. Quite a famous engine.Of course, this is not that exact engine as it burned up in the earth's atmosphere after being jettisoned when the Apollo 13 crew returned to earth in the Command Module.
Flown engines, of course, are either left on the surface of the moon (Apollo 11, 12, 14, 15, 16, 17), crashed into the moon (Apollo 10), or burned up in earth’s atmosphere (Apollo 5, 9, 13).
The combustion chamber consists of an ablative-lined titanium alloy case to the 16:1 area ratio. Fabrication of the 6A1-4V alloy titanium case was accomplished by machining the chamber portion and the exit cone portion from forgings and welding them into one unit at the throat centerline. The ablative liner is fabricated in two segments and installed from either end. The shape of the nozzle extension (not installed on the example in this collection) is such that the ablative liner is retained in the exit cone during transportation, launch and boost. During engine firing, thrust loads force the exit cone liner against the case. The titanium head end assembly which contains the Pintle Injector and propellant valve subcomponents is attached with thirty-six A-286 steel ¼ inch bolts.
In order to keep the maximum operating temperatures of the titanium case in the vicinity of 800 degrees (F), the ablative liner was designed as a composite material providing the maximum heat sink and minimum weight. The selected configuration consisted of a high density, erosion-resistant silica cloth/phenolic material surrounded by a lightweight needle-felted silica mat/phenolic insulation.
The Pintle Injector, unique to TRW designed liquid propulsion systems, provides improved reliability and less costly method of fuel oxidizer impingement in the thrust chamber then conventional coaxial distributed-element injectors typically used on liquid biproellant rocket engines.
Dry mass: 300 pounds (with Columbian Nozzle Extension Installed)
Length: 51 inches - Gimbal attachment to nozzle tip (minus nozzle extension)
Maximum diameter: 34 inches (minus nozzle extension)
Mounting: gimbal attachment above injector
Engine cycle: pressure fed (15.5 atm reservoir)
Oxidizer: 50/50 N_2O_4/UDMH at 8.92 kg/s
Fuel: monomethyl hydrazine at 5.62 kg/s
O/F ratio: 1.60
Thrust: 42.923 kN vac
Specific impulse: 303 s vacuum
Expansion ratio: 16:1, 43:1 (with Expansion Nozzle)
Cooling method: quartz phenolic chamber ablation and columbium (niobium) nozzle radiation
Chamber pressure: 7.1 atm
Ignition: hypergolic, started by 28 V electrical signal to on/off solenoid valves
Burn time: 500 s for total of 5 starts; 10 350 s single burn
Thanks to Scott Schneeweis for the technical description of this artifact.