1. Final Slides Attitude Control System (ACS) – Lunar Transfer
Brian Erson
Final Slides
Attitude Control System (ACS) – Lunar Transfer

2. Environmental Pertubations contribute to trajectory offsets
Sun sensor Tells reaction wheels to make adjustments
Thrusters fire to desaturate reaction wheels
Star Sensors maintain inertial reference
ACS aides OPS in maintaining trajectory

3. Importance of Attitude Control During Lunar Transfer
Thrust Misalignment and Environmental perturbations contribute to trajectory offsets
Reaction Wheels and Thrusters provide control to OTV during Lunar Transfer

4. Final ACS Numbers 100g payload 10kg payload Large payload
Device
Mass (kg)
Cost ($)
Power Required(W)
Volume (m3)
VF STC 1 (star sensor)
6.4
133,333
20.4
0.0163
VF SNS (sun sensor)
0.7 5
VF MR 4.0
10.4 76
thruster
0.36
1,500 --
propellant
0.02
100
Inert Mass
1.9
1,000
Totals
19.8
403,000
101.4
Device
Mass (kg)
Cost ($)
Power Required(W)
Volume (m3)
VF STC 1 (star sensor)
6.4
133,333
20.4
0.0163
VF SNS (sun sensor)
0.7 5
VF MR 10.0 20
120
thruster
0.36
1,500 --
Propellant
1.26
100
Inert Mass
3.02
1,000
Totals
31.74
403,000
145.4
Large payload
Note: Star and Sun sensors remain on Lander after separation
Device
Mass (kg)
Cost ($)
Power Required(W)
Volume (m3)
VF STC 1 (star sensor)
6.4
133,333
20.4
0.0163
VF SNS (sun sensor)
0.7 5
VF MR 19.6 42
280
0.0258
H202 thruster
0.36
2,500 --
H202 Propellant
10.6
100
Inert Mass
13.84
1,000
Totals
73.9
404,000
305.4
0.068
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