Page 74 - Apollo Moonships

72 On bOard apOllO mOOnships
REACTION CONTROL SYSTEM
Composed of 16 small rocket engines arranged in clusters of four around the ascent stage, the Reaction Control System (RCS) provided thrusts to move the lunar lander in yaw, pitch, and roll directions and stabilize the ship in flight. The system also provided the thrust required to separate the LEM from the Command-Service Module (CSM). The RCS rocket engines, which delivered 94 pounds of thrust each, used Aerozine 50 as fuel and nitrogen tetroxide as an oxidizer.
RCS CLUSTER Thruster (4)
Oxidizer inlet line
Oxidizer valve Assembly
Fuel inlet line
Heater and injector head assembly
Fuel valve Assembly
1 ASCENT STAGE RCS AND MPS
1
2
3
10
11
12
2 DESCENT STAGE MPS
14
5
4
6
7
9
13
8
15
18
MPS TANKS PROFILE
APS propellant tanks capacity:
APS total fuel:
APS total oxidizer:
APS helium tanks capacity:
APS total helium:
DPS propellant tanks capacity:
DPS total fuel:
DPS total oxidizer:
DPS supercritical helium tank capacity: DPS total supercritical helium:
DPS ambient helium tank capacity:
RCS
The c oxidiz feet. I nitrog
16 17
19 20
MAIN PROPULSION SYSTEM
The Main Propulsion System (MPS) encompassed two independent units: the Descent Propulsion Section (DPS) and the Ascent Propulsion Section (APS). The function of each
one was completely different: the first of them reduced the rate of descent to the lunar surface and provided impulse to reach the landing area. For its part, the second section lifted the ascent stage off the moon’s surface to the lunar orbit, where the ship rendezvoused and docked with the CSM. While performing their respective tasks, both propulsion sections operated in conjunction with the RCS. The crew could use
any of the two propulsion sections to return to the CSM if an emergency arose during the lunar landing. Both propulsion units were fed by the same propellant: aerozine 50 (fuel) and nitrogen tetroxide (oxidizer). Because the DPS performed more complicated tasks (it was responsible for driving the entire Lunar Excursion Module until the ship landed on the moon), it was not only more large and sophisticated than the APS but also carried three times more propellant.
RCS AND MPS MAIN COMPONENTS
1 RCS oxidizer tank A
2 RCS fuel tank A
3 RCS helium (He) tank A
4 RCS fuel tank B
5 RCS He pressure regulator
6 RCS oxidizer tank B
7 RCS helium tank A
8 APS oxidizer tank
9 Ascent engine
10 APS fuel tank
11 APS helium tank (2)
12 APS He pressure regulator (2) 13 RCS engine cluster (4)
14 DPS fuel tank
15 DPS oxidizer tank
16 Descent engine
17 DPS oxidizer tank
18 DPS fuel tank
19 DPS ambient helium tank
20 DPS supercritical helium tank
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