AAE450 Spring 2009 Hopper Trajectory February 26, 2009 [Alex Whiteman] [Mission Ops] [Lunar Descent] Page 1

AAE450 Spring 2009 Trajectory conditions  Must travel at least 500m in one hop  Vertical, soft landing  Pitch rate constrained by 17.5 Nm attitude control system torque  Must stay a safe distance above lunar surface Assumptions  Constant Thrust to Mass ratio for each phase of trajectory Trajectory Design Page 2

AAE450 Spring 2009 Trajectory Results  Time of flight: 86 sec  Propellant used: 5.92 kg  Thrust levels: N  Range: 561 m  Maximum pitch angle: 21 deg Notes  Propellant mass used and time of flight do not vary with maximum altitude of trajectory  Trajectory requires accurate thrust and attitude control  Significant mass savings compared to rover Trajectory Phases  Ascent: Pitch over to positive 21° from vertical then pitch back to vertical  Descent: Pitch over to negative 21 ° from vertical then pitch back to vertical Page 3

AAE450 Spring 2009 Backup Slide 1 MATLAB EOM Script Page 4

AAE450 Spring 2009 Backup Slide 2 MATLAB EOM Script (cont.) Page 5