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Ascent propulsion system

Apollo Lunar Module rocket engine

Field	Value
name	Ascent propulsion system (APS)
image	Apollo Lunar Module Ascent Engine.jpg
caption	Apollo LM ascent engine
country_of_origin	United States
date	1964–72
manufacturer	Bell Aircraft / Rocketdyne
purpose	Lunar Ascent Stage/Spacecraft propulsion
predecessor	Bell 8247
successor	RS-18
status	Retired
type	liquid
oxidiser	[](dinitrogen-tetroxide)
fuel	Aerozine 50
mixture_ratio	1.6
cycle	Pressure-fed
pumps	None
combustion_chamber	1
nozzle_ratio	46
thrust(Vac)	3500 lbf
thrust_to_weight	16.7 (weight on Earth)
chamber_pressure	120 psi
specific_impulse_vacuum	311 isp
burn_time	200 seconds
restarts	Designed for 1 restarts
length	510 in
diameter	100 in
dry_weight	209.6 lb
used_in	Lunar module as ascent engine
references

|thrust(Vac) = 3500 lbf |thrust(SL) =

The ascent propulsion system (APS) or lunar module ascent engine (LMAE) is a fixed-thrust hypergolic rocket engine developed by Bell Aerosystems for use in the Apollo Lunar Module ascent stage. It used Aerozine 50 fuel, and oxidizer. Rocketdyne provided the injector system, at the request of NASA, when Bell could not solve combustion instability problems.

Origins

The LMAE traces its origin to the earlier Bell Aerosystems engines (8096, 8247) used in the RM-81 Agena, the rocket upper stage and satellite support bus developed by Lockheed initially for the canceled WS-117L reconnaissance satellite program. The Agena served as an upper stage for several defense, intelligence, and exploration programs: SAMOS-E, SAMOS-F (ELINT Ferret) and MIDAS (Missile Defense Alarm System) military early-warning satellites, Corona photo intelligence program, and the Ranger and Lunar Orbiter lunar probes.

The Lockheed Agena target vehicle using the Bell 8247 engine was qualified for 15 restarts for NASA's Project Gemini.

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 a Titan 34B.

Development

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 and CSM 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.

The engine developed about 1600 lbf of thrust, which produced a velocity of 3,200 meters per second from lunar launch, to LOR, and CM docking.

RS-18 Engine

Rocketdyne brought the lunar module ascent engine out of its 36-year retirement in 2008 for NASA's Exploration Systems Architecture Study (ESAS) engine testing, re-designated it as RS-18, and reconfigured the non-throttleable hypergolic engine to use LOX/methane.

References

(February 7, 1966). "Apollo spacecraft liquid primary propulsion systems". [[NASA]], [[Johnson Space Center.
(1997). "Technology and the Air Force A Retrospective Assessment". [[United States Air Force.
[[Lockheed Missiles and Space Company]]. (February 25, 1972). "Shuttle/Agena Study". [[NASA]].
Grassly, Sarah A.. (June 1969). "Agena Flight History as of 31 December 1967". [[Air Force Systems Command]].
Parsch, Andreas. (February 27, 2003). "Lockheed RM-81 Agena".
(September 20, 2007). "Chariots for Apollo: A History of Manned Lunar Spacecraft".
"LM Ascent Propulsion". [[Encyclopedia Astronautica]].
(2 September 2008). "Heritage lunar engine fired up once again". [[Pratt & Whitney Rocketdyne]].

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

rocket-engines-using-hypergolic-propellant apollo-program-hardware spacecraft-propulsion rocket-engines-using-the-pressure-fed-cycle

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