Lunar Lander Handling Qualities Terminal Descent to Touchdown

1. Lunar Lander Handling QualitiesTerminal Descent to Touchdown Dr. Karl Bilimoria NASA Ames Research Center “Go for Lunar Landing” Conference Tempe, AZ 4 – 5 March 2008

2. Background • Handling Qualities • Ease & precision with which the pilot can execute a flying task • HQs depend on vehicle response, guidance cues, inceptors, etc. • Comprehensive standards exist for aircraft • NASA has initiated an effort to study handling qualities of piloted spacecraft designed for Constellation program • Lunar Lander experiment • May 2007 at Ames, on the Vertical Motion Simulator (VMS) • A first step in the handling qualities effort

3. Precision Landing Task: Horizontal Profiles Two horizontal profiles • Centerline approach • 250 ft offset approach 1,350 ft Landing Site Land within 15 ftof target center Offset distance= 250 ft Centerline Approach Left Offset Approach

4. Precision Landing Task: Vertical Profile Trajectory based on Apollo missions: “Low Gate” to Touchdown INITIAL CONDITIONS: Distance = 1,350 ft Altitude = 500 ft Horizontal speed = 60 fps Vertical speed = –16 fps Pitch angle = 16 deg Reference Trajectory 95 sec to touchdown Uncontrolled Trajectory 31 sec to impact Dist = 0 Alt = 150 ft Horiz spd = 0 Vert spd = –3 fps

5. Out the window field of view Simulator Cab Layout

6. Cockpit Displays Guidance cues: • Roll, pitch, and yaw angles • Forward and lateral speeds • Altitude rate

7. Lunar Lander Experiment Objectives • Evaluate a basic model of Apollo Lunar Module • Study handling qualities for various combinations of: • Control power (various levels of acceleration) • Guidance (ON or OFF) Pilots fly 3 approaches in each cell – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments

8. Control Power Study – Guidance On Task Load Index Rating Handling Qualities Rating Not satisfactory for tasks that couldresult in crew or vehicle loss Level 3: Improvement mandatory Level 2: Deficiencies warrant improvement Satisfactory for tasks that couldresult in crew or vehicle loss Level 1: Satisfactory without improvement Evaluating a basic model of Apollo Lunar Module

9. Concluding Remarks • Control power study • Nominal configuration model is close to Level 1 boundary • Handling qualities degrade rapidly after control power drops below 50% of nominal value • Guidance is essential for precision landing task • Lateral offset approach not flyable without guidance • Centerline approach very difficult to fly without guidance • Suggested discussion topic:Does a ground-based simulator with high motion fidelity negate the need to build a LLRV-like vehicle for Cx?