1. 1 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities NESC GN&C Technical Discipline Team Webcast Series NESC GN&C Technical Discipline Team Webcast Series

2. 2 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Volume Control* Polls (if any) Ask a Question Files (if any) *Hover your cursor over the speaker icon to access the volume slider.

3. 3 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Dr. Karl Bilimoria Fundamentals of Piloted Spacecraft Handling Qualities NESC GN&C Webcast 18 January 2012

4. 4 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Handling qualities background Motivation for spacecraft handling qualities work Piloted evaluations of handling qualities –Orbital docking –Lunar landing Lessons learned Outline

5. 5 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Handling Qualities Background Handling Qualities –Ease and precision with which pilot can execute a flying task [Cooper & Harper] –Depend on vehicle dynamics, control systems, visual cues, inceptors, etc. –Good handling qualities give pilots a “buffer” to address off-nominal events Cooper-Harper scale is widely used for handling qualities rating –Pilot is briefed to fly task and achieve specified performance parameters –Pilot rates handling qualities based on performance and effort, along an ordinal scale of 1 (best) to 10 (worst)  Pilot commentary is very important –Handling qualities levels Level 1 Required for normal operations Level 2 OK for some off-nominal operations Level 3 OK only for transitioning to safe mode after major failure/disturbance

6. 6 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Cooper-Harper Rating Scale Level 1 Level 2 Level 3 require

7. 7 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Video: F-8 Digital Fly-by-Wire Experiment

8. 8 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Spacecraft with good handling qualities can provide operational benefits by reducing training costs and mission risk NASA requirements for human-rated spacecraft (NPR 8705.2B) –Manual control of flight path and attitude –Satisfactory handling qualities There are no design standards for spacecraft handling qualities A comprehensive knowledge base would help spacecraft builders make design trade-offs to meet handling qualities requirements Why Study Spacecraft Handling Qualities?

9. 9 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Several spacecraft handing qualities studies were conducted by NASA during 2007–10 Flying tasks studied –Lunar Landing –Proximity Operations; Docking –Atmospheric Entry Studies at Ames/Langley Research Centers explored a range of design options for generic spacecraft configurations Studies at the Johnson Space Center evaluated the “point design” of the Orion spacecraft Recent NASA Studies on Spacecraft HQs

10. 10 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities This briefing covers four experiments conducted during 2007-08 –Lunar landing (2) –Docking with ISS (2) –Experiments conducted in the Ames Vertical Motion Simulator (VMS), which has the largest motion travel of any ground-based flight simulator –Each experiment ran for about 3 weeks Handling qualities evaluated by a distinguished group of pilots –26 Space Shuttle pilots –4 NASA test pilots –3 Apollo Lunar Module pilots –Each experiment had 6 to 14 pilots Overview of Selected Experiments

11. 11 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Docking Experiments

12. 12 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Initial conditions –Axial separation of 10 ft between docking ports –Axial closure rate of 0.1 ft/sec –Radial position error between docking ports Pilot nulls position errors using hand controller and cross-hairs overlay (reticle) on camera –Coupling effects excite attitude dynamics –Control system holds attitude automatically Docking performance requirements –Radial position error less than 1.5 inches –Error limits on attitude, angular velocity, closure rate, and radial velocity Flying Task IC 2 IC 3 IC 1IC 4 IC = Initial Condition

13. 13 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Simulator Cockpit Layout Translational hand controller Cockpit displays

14. 14 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Evaluate handling qualities as a function of: Translation-into-rotation coupling (distance from control jets to center of mass) Translational control response type (firing logic of control jets) Objective – Docking Experiment #1 Response Type  Coupling  Single Pulse Jets Continuous Jets Proportional Translation Rate Command with position hold Discrete Translation Rate Command with position hold Zero 50% 100% baseline (Orion) For each configuration, pilots provided: – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments For each configuration, pilots provided: – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments Control Jets Center of mass

15. 15 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Key Results – Docking Experiment #1 Cooper-Harper ratings from 14 pilots flying 435 dockings Coupling effects degrade handling qualities, regardless of response type Baseline (100%) coupling configuration rated Level 2 for docking task Coupling effects degrade handling qualities, regardless of response type Baseline (100%) coupling configuration rated Level 2 for docking task Response Type and Coupling SPJ = Single Pulse Jets CJ = Continuous Jets PTRC = Proportional Translation Rate Command with position hold DTRC = Discrete Translation Rate Command with position hold Proportion of Ratings

16. 16 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Evaluate the effect of pilot tools designed to enhance handling qualities Objective – Docking Experiment #2 Dead-band Indicator Flight Path Marker Translation Guidance Feed-forward control Selected combinations of above tools Coupling level: 100% baseline (Orion) Translational control response type: Single Pulse Jets Coupling level: 100% baseline (Orion) Translational control response type: Single Pulse Jets

17. 17 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Key Results – Docking Experiment #2 Use of pilot tools, especially in combination, improves docking handling qualities Use of feed-forward control provides solid Level 1 handling qualities for docking Use of pilot tools, especially in combination, improves docking handling qualities Use of feed-forward control provides solid Level 1 handling qualities for docking Pilot Tools None = Reticle only DBI = Dead-band indicator FPM = Flight-path marker THC = Translation guidance FF = Feed-forward control Pilot Tools None = Reticle only DBI = Dead-band indicator FPM = Flight-path marker THC = Translation guidance FF = Feed-forward control Cooper-Harper ratings from 12 pilots flying 210 dockings Pilot Tools Proportion of Ratings

18. 18 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Using only reticle: –Translation-into-rotation coupling degrades handling qualities –Significant pilot effort required to decompose the rotation/translation components of dock position error –Baseline (100%) coupling configuration rated as Level 2 for docking Pilot tools can improve handling qualities –Good ratings for dead-band indicator and flight-path marker combination Feed-forward control provides solid Level 1 handling qualities and significantly reduces propellant usage –Advanced attitude control system makes coupling transparent to pilot –Predictable motion  less pilot control inputs  less propellant usage Conclusions – Docking Experiments

19. 19 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Lunar Landing Experiments

20. 20 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Flying Task: Overview 1,350 ft (0.26 mi) Landing Site Centerline Approach Offset Approach (250 ft) Initial conditions –1,350 ft range with 250 ft lateral offset –500 ft altitude Pilot controls trajectory using two hand controllers –Rotation controller for coarse trajectory changes to arrive over landing site –Translation controller available for fine trajectory changes over landing site Requirements for precision landing –Touchdown position error less than 15 ft –Limits on attitude, angular velocity, forward speed, descent rate, propellant

21. 21 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Flying Task: Vertical Profile Reference Trajectory 95 sec to touchdown Reference Trajectory 95 sec to touchdown Uncontrolled Trajectory 31 sec to impact Uncontrolled Trajectory 31 sec to impact Altitude (ft) Fwd speed = 60 fps Sink rate = 16 fps Sink rate = 3 fps Pitch up 16 deg Vertical trajectory derived from Apollo missions Manual control from Low Gate to touchdown

22. 22 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Simulator Cab Layout Out the window field of view

23. 23 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities For precision lunar landing task, study effects on handling qualities due to: Control power (accelerations provided by control jets) Guidance cues (roll and pitch error bars) Objective – Lunar Landing Experiment #1 Control Power  Guidance Cues  15% 20% 25% 30% 50% 100% (Apollo) ON (Offset Approach) OFF (Centerline Approach) For each configuration, pilots provided: – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments For each configuration, pilots provided: – Cooper-Harper Rating – Workload Rating (NASA-TLX) – Comments

24. 24 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Key Results – Lunar Landing Experiment #1 Cooper-Harper ratings from 6 pilots flying 108 landing approaches Offset approach with guidance on Handling qualities qualities degrade as control power decreases Lateral offset approach very difficult to fly without guidance Handling qualities qualities degrade as control power decreases Lateral offset approach very difficult to fly without guidance Control Power (% of nominal) Proportion of Ratings

25. 25 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities For precision lunar landing task, study effects on handling qualities due to: Control power (accelerations provided by control jets) Rotation command sensitivity (angular rate at full inceptor displacement) Objective – Lunar Landing Experiment #2 Control Power  Rotation Cmd. Sensitivity  68%100% (Altair) 181%262% (Apollo) 3 deg/sec 7 deg/sec Propellant Slosh (2) 12 deg/sec 20 deg/sec For each configuration, pilots provided: – Cooper-Harper Rating – Workload Rating (NASA-TLX, Bedford) – Comments For each configuration, pilots provided: – Cooper-Harper Rating – Workload Rating (NASA-TLX, Bedford) – Comments

26. 26 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Key Results – Lunar Landing Experiment #2 Cooper-Harper ratings from 12 pilots flying 418 landing approaches Dots indicate experiment configurations Level 3 region (extrapolated) Baseline (100%) control power configurations rated as Level 2 for precision landing Baseline (100%) Control Power Level 1 Level 2 Handling qualities degrade

27. 27 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Guidance cues are important for precision landing task –Lateral offset approach very difficult to fly without guidance –Centerline approach challenging to fly without guidance Handling qualities are affected by both control power and rotation command sensitivity –Level 1 handling qualities in only a small region of this design space –For a fixed control power, adjusting rotation command sensitivity provides a modest improvement in handling qualities at “no cost” Baseline (100%) control power configurations were rated as Level 2 handling qualities for precision landing –In a follow-up study, enhanced cockpit displays and control systems provided improved handling qualities Conclusions – Lunar Landing Experiments

28. 28 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Cooper, G.E. and Harper, R.P., “The Use of Pilot Rating in the Evaluation of Aircraft Handling Qualities,” NASA TN D-5153, April 1969. Bailey, R.E., Jackson, E.B., Bilimoria, K.D., Mueller, E.R., Frost, C.R., and Alderete, T.S., “Cooper-Harper Experience Report for Spacecraft Handling Qualities Applications,” NASA TM-2009-215767, June 2009. Bilimoria, K.D., “Effects of Control Power and Guidance Cues on Lunar Lander Handling Qualities,” Journal of Spacecraft and Rockets, Vol. 46, No. 6, November-December 2009, pp. 1261–1271. Mueller, E., Bilimoria, K.D., and Frost, C., “Effects of Control Power and Inceptor Sensitivity on Lunar Lander Handling Qualities,” Journal of Spacecraft and Rockets, Vol. 48, No. 3, May-June 2011, pp. 454–466. Mueller, E., Bilimoria, K.D., and Frost, C., “Improved Lunar Lander Handling Qualities through Control Response Type and Display Enhancements,” Paper No. 2010-8025, AIAA Guidance, Navigation, and Control Conference, August 2010; to appear in Journal of Spacecraft and Rockets. Bailey, R., Jackson, B., Goodrich, K., Ragsdale, A., Neuhaus, J., and Barnes, J., “Investigation of Reaction Control System Design on Spacecraft Handling Qualities for Docking,” Journal of Guidance, Control, and Dynamics, Vol. 32, No. 6, November-December 2009, pp. 1723–1735. Mueller, E., Bilimoria, K.D., and Frost, C., “Dynamic Coupling and Control Response Effects on Spacecraft Handling Qualities During Docking,” Journal of Spacecraft and Rockets, Vol. 46, No. 6, November-December 2009, pp. 1288–1297. Bilimoria, K.D., Mueller, E.R., and Frost, C.R., “Handling Qualities Evaluation of Piloting Tools for Spacecraft Docking in Earth Orbit,” Journal of Spacecraft and Rockets, Vol. 48, No. 5, September-October 2011, pp. 846–855. Stephens, J.-P., Vos, G.A., Bilimoria, K.D., Mueller, E.R., Brazzel J., and Spehar, P., “Orion Handling Qualities During ISS Proximity Operations and Docking,” Paper No. 2011-6261, AIAA Guidance, Navigation, and Control Conference, August 2011. Bilimoria, K.D. and Mueller, E.R., “Handling Qualities of a Capsule Spacecraft during Atmospheric Entry,” Paper No. 2010-8308, AIAA Guidance, Navigation, and Control Conference, August 2010; to appear in Journal of Spacecraft and Rockets. Tigges, M.A., Bihari, B.D., Stephens, J.-P., Vos, G.A., Bilimoria, K.D., Mueller, E.R., Law, H.G., Johnson, W., Bailey, R.E., and Jackson, B., “Orion Capsule Handling Qualities for Atmospheric Entry,” Paper No. 2011-6264, AIAA Guidance, Navigation, and Control Conference, August 2011. Selected Publications

29. 29 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities Questions? Contact: karl.bilimoria@nasa.gov

30. 30 Ames Research Center Karl Bilimoria 18 Jan 2012 Fundamentals of Piloted Spacecraft Handling Qualities “Fundamentals of Deep Space Mission Design” Dennis Byrnes (JPL), on 21 March 2012 “Fundamentals of Launch Vehicle Flight Control” John Rakoczy (MSFC), on 16 May 2012 “Fundamentals of Spacecraft Attitude Control” Dave Mangus (GSFC), on 18 July 2012 “Fundamentals of Aircraft Flight Control” TBD, on 19 September 2012 “Fundamentals of Adaptive Control” Irene Gregory (LaRC), on 21 November 2012 Upcoming NESC GN&C Webcasts