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

2 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown 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 Background

3 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown Precision Landing Task: Horizontal Profiles Two horizontal profiles –Centerline approach –250 ft offset approach Two horizontal profiles –Centerline approach –250 ft offset approach 1,350 ft Offset distance = 250 ft Landing Site Centerline Approach Left Offset Approach Land within 15 ft of target center

4 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown Precision Landing Task: Vertical Profile INITIAL CONDITIONS: Distance = 1,350 ft Altitude = 500 ft Horizontal speed = 60 fps Vertical speed = –16 fps Pitch angle = 16 deg 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 Reference Trajectory 95 sec to touchdown Uncontrolled Trajectory 31 sec to impact Uncontrolled Trajectory 31 sec to impact Horiz spd = 0 Vert spd = –3 fps Dist = 0 Alt = 150 ft Trajectory based on Apollo missions: “Low Gate” to Touchdown

5 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown Simulator Cab Layout Out the window field of view

6 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown Cockpit Displays Guidance cues: –Roll, pitch, and yaw angles –Forward and lateral speeds –Altitude rate Guidance cues: –Roll, pitch, and yaw angles –Forward and lateral speeds –Altitude rate

7 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown 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) Lunar Lander Experiment Objectives Control Power  Guidance  0.15X 0.2X 0.25X 0.3X 0.5X 1X (Baseline) ON Offset Approach OFF Centerline Approach Pilots fly 3 approaches in each cell – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments Pilots fly 3 approaches in each cell – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments

8 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown Control Power Study – Guidance On Handling Qualities Rating Task Load Index Rating Level 1: Satisfactory without improvement Level 3: Improvement mandatory Level 2: Deficiencies warrant improvement Satisfactory for tasks that could result in crew or vehicle loss Not satisfactory for tasks that could result in crew or vehicle loss Evaluating a basic model of Apollo Lunar Module

9 Ames Research Center Karl Bilimoria 5 March 2008 Lunar Lander Handling Qualities – Terminal Descent to Touchdown 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? Concluding Remarks