1. Lunar Descent Trajectory
February 5th, 2009
[John Aitchison] [Mission Ops]

2. [John Aitchison] [Mission Ops]
Descent Trajectory
Goal
Determine trajectory, attitude, burn time, range & altitude
EOM Derivation Assumptions
Moon/spacecraft system, spherical & does not rotate, point masses
2-D problem
T/m varies only with changing propellant mass (no throttling)
[John Aitchison] [Mission Ops]

3. [John Aitchison] [Mission Ops]
Useful Numbers
Variability with:
Vehicle Mass
Thrust Capability
Lunar Parking Orbit
Time (s)
Action
Downrange (km)
Altitude (km)
0.0
Retro 15
170.3
27°
170.1
5.7
207.5
Vertical
175.4
0.9
222.1
Touchdown
[John Aitchison] [Mission Ops]

4. [John Aitchison] [Mission Ops]
Code (pg. 1)
[John Aitchison] [Mission Ops]

5. [John Aitchison] [Mission Ops]
Code (pg. 2)
[John Aitchison] [Mission Ops]

6. [John Aitchison] [Mission Ops]
Code (pg. 3)
[John Aitchison] [Mission Ops]

7. [John Aitchison] [Mission Ops]
Code (pg. 4)
[John Aitchison] [Mission Ops]

8. [John Aitchison] [Mission Ops]
Coordinate System
[John Aitchison] [Mission Ops]

9. Coordinate System Definitions
[John Aitchison] [Mission Ops]

10. [John Aitchison] [Mission Ops]
Assumptions
[John Aitchison] [Mission Ops]

11. [John Aitchison] [Mission Ops]
Calculations (pg. 1)
[John Aitchison] [Mission Ops]

12. [John Aitchison] [Mission Ops]
Calculations (pg. 2)
[John Aitchison] [Mission Ops]

13. [John Aitchison] [Mission Ops]
Calculations (pg. 3)
[John Aitchison] [Mission Ops]

14. [John Aitchison] [Mission Ops]
Calculations (pg. 4)
[John Aitchison] [Mission Ops]