N ASA CONTRACTOR REPORT LOAN COPY: RETURN TO AFWI, (WLIL-2) KIRTLAND AFB, N MEX VISUALSENSING OFSPACECRAFT GUIDANCEINFORMATION Earth Orbit Rendezvous Maneuvers by S. Seidenstein, W. K. Kincuid, Jr., G. L. Kyeezer, und D. H. Utter Prepared by LOCKHEED MISSILES & SPACE CO. Sunnyvale, Calif. for LangZey Research Center TECH LIBRARY KAFB, NM .."... .. .~~ . 00603ib NASA CR-1214 VISUAL SENSING OF SPACECRAFT GUIDANCE INFORMATION Earth Orbit Rendezvous Maneuvers By S. Seidenstein, W. K. Kincaid, Jr., G. L. Kreezer, and D. H. Utter Distribution of this report is provided in the interest of informationexchange. Responsibility for the contents resides in the author or organization that prepared it. Prepared under Contract No. NAS 1-6801 by LOCKHEED MISSILES & SPACE CO. Sunnyvale, Calif. for Langley Research Center NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ~~__~". For sale by the Clearinghouse for Federol Scientific and Technical Information Springfield, Virginia 22151 - CFSTl price $3.00 CONTENTS -Page TAELES V ILLUSTRATIONS viii SUMMARY 1 INTRODUCTION 1 RENDEZVOUS 4 Rendezvous Mission Phases 4 Mission Phase and Guidance Schemes 5 Visual Referencesand Techniques for Obtaining Parameters 6 References 7 PHYSICALCHARACTERISTICS OF THE VISUAL ENVIRONMENT 10 Introduction 10 Orbit Related Characteristics il Target Vehicle Chara.cteristics 15 Spacecraft Characteristics 21 Visual Sensitivity and the Physical Environment 24 Operational Flight Experience 25 References 28 MEASURINGVISUAL CAPABILITIES 30 References 35 SENSITIVITY OF THE EYE 36 General Characteristics 36 Pupil Responses 38 Retinal Sensitivity 40 Differential Sensitivity and Visibility 53 References 57 SENSING MOTION AND CROSS RPINGE INFORMATION 61 Introduction 61 Phenomenal Characteristics of Motion 62 Definitions of Thresholds for Motion Perception 64 Absolute Thresholds for Real Motion 70 DifferenceThresholds 75 Dynamic Visual Acuity 79 References 82 iii CONTENTS (cont Id) Page rMGE AND RANGE RATE DETERMINATIONS Introduction Perception of Absolute Range Perception of Relative Range Range Rate Brightness as a Source of Range Information References VISUALAIDS FOR SPACE NAVIGATION CONCLUSIONS AND RECOMMENDATIONS 128 APPENDIXES A Symbols 239 R ConversionFactors 243 iv TABLES Table -Page I Range of Parameters for Selected Guidance Schemes I1 Equations of Motion for Selected Guidance Schemes I11 Techniques for Obtaining Selected Guidance Schemes Typical BackgroundLuminance Sources and Their Luminance V Stellar Magnitudesand their Corresponding Earth Sea Level Illuminance VI The Photometric Characteristics of Plates or Discs,Spheres, Cylinders andCones VI I Space Vehicle Surface Coatings and their Approximate Reflectivities VI11 Running Light Characteristics for Apollo and Gemini Vehicles 141 IX Gemini and Apollo Vehicles Acquisition Beacon Characteristics 142 x Spacecraft Window Characteristics 143 XI Guidance and Navigation Subsystem Optics and LM Alignment Optical Telescope (AOT) Optical Characteristics 144 XI I Operational Flight Experience Data 145 XI11 Functional Characteristics of the Retina 147 XN Changes in Absolute Threshold of the Dark- AdaptedEye as a Function of Illumination Transients 148 V TABLES (Cont I d) Table -Page xv Effects of Pre-exposure Conditions on the Course of Subsequent Dark Adaptation 149 XVI AbsoluteThresholds forthe Detection of AngularMotion; Basic Studies XVII AbsoluteThresholds for theDetection of Angular Motion; Applied Studies XVIII StimulusConditions Present in Measurements of Au 152 XIX Methodologyused inthe Measurements of 1.53 xx Angular Rate Thresholdsfor Two Stimuli Moving in Opposing Directions XXI DifferentialAngular Rate Thresholds as a Function of Method of Presentation XXII DifferenceThresholds for Velocity XXIII Delineation of the Cues of Distance XXIV ErrorsinEstimates of AbsoluteDistance XXV SupplementalConditions Investigationsin of Estimated Absolute Distance 161 XXVI Terms usedfor Distance and Size 162 XXVII Sub-Problems inInvestigations in Movement Parallax XXVIII Equivalenceof Symbols in Diagrams for Parallax and Stereopsis 164 xxlx ParallaxRatioThresholds 165 xxx' ParallaxDifferential Angular Velocity Thresholds (w) 166 XXXI Change inParallax Thresholds with Increase in Magnitude of Independent Variable vi TAXES (Cont 1 d) -Table Page XXXII Linear Depth IntervalsCalculated for Different Disparity Angles and Repre- sentative Fixation Distances 168 XXXIII StereopticThresholds: Magnitude of vt 169 XXXIV Stimulus-ParametersEffecting Stereoptic Threshold (qt) Icxxv Receptor-ParametersEffecting Stereoptic Thresholds (qt) vii ILLUSTRATIONS Figure 1. Pitch Plane Geometry for Guidance SchemeNo.1: Inertial Line-of-Sight Collision Course 2. Pitch Plane Geometry for Guidance SchemeNO. 2: Rotating Line-of-Sight Collision Course 3- Line-of-Sight Relations BetweenComanded Module and Spacecraft 4. Physical Environment Parameters and Their Relationships 5. Typical Spacecraft Illumination Environmentas a Function of Mission and/or its Orbit Position 6. Maximum Lineof Sight Distance and Time in Dark for Earth Orbiting Spacecraft 177 7. Star Density Versus Magnitude for Three OfSizes Field of View 178 8. Minimum Visual Acuityas a Function of Contrast Ratio and Background Luminance 179 9. Surface Brightness of Spacecraft Corona as a Function ofMass Ejecti0.n Rate 180 10 Critical Visual Angle for Point Sources as a Function of Background Luminance 181 11. Distance Beyond Whicha Target isa Point Source 182 12. Illumination at the Eye Versus Rangefor a Sunlit Diffuse Flat Plateor Disc of Area (A) 18 3 13 Target Brightness Versus Range afor Sunlit Diff'use Flat Plate or Disc of (A)Area 18 4 14. Illumination at the Eye Versus Range for a Sunlit Diffuse Sphere 18 5 15 Target Brightness Versus Range for a Sunlit Dif- fuse Sphere 186 16. Illumination at the Eye Versus Rangefor a Sunlit Diffuse Cylinder of Radius (r) and Length (h) 187 viii Figure Page 1-7 Target Brightness Versus Rangefor a Sunlit Dif- fuse Cylinderof Radius (r) and Length (h) 188 Illumination at the Eye Versus Range for a Sunlit Diffuse Cone of Height(h) and Cone Half Angle( ) 19 Target Brightness Versus Rnage for a Sunlit.Dif- fuse Cone of Height(h) and Cone Half 20. Reflection of Collimated Light by a Specular and a Diffuse Sphere 21. Relative Visibility Versus Wavelength for the Light Adapted Eye 192. 22. Intensity Variation asa Function of Viewing Angle for a Typical Xenon Flash Lamp 19 3 23. Relative Intensityof a Justvisible Flash aas Function of Flash Duration - 194 24. Spacecraft Internal Illumination 195 (a) Gemini V Inflight Measurements (b) Gemini VI Postflight Simulationof Inflight Conditions 25. Threshold Illuminationfrom a Fixed Achromatic Point Sourceas a Fynction of Background 'Brightness Inflight Target Visibility Datafor Gemini Flights "he Relationship of Pupil Size to Adapting Luminance Pupil Responses to a Short ofFlash Light Amplitude, Duration and Latencyof Pupil Responses to 1 Second Light Flashes 2 01 30 Pupil Responses to a Seriesof Light Flashes 201 31 Pupil Responses to a Stepfunction Changein Luminance 202 32 Distribution of Rods and Cones in the Retina 203 33. The General Course of Dark Adaptation 204 ix I Figure Page 34. Variation in Dark-Adaptation Over Repeated Measures on the Same Observers 205 35. Luminance in the Light-Adapted Right Eye Necessary for a Constant Levelof Subjective Brightness as a Function 07 Time in Dark 206 36. Subjective Brightnessof Different Luminances in a Light-Adapted Eye as a Functionof Time in Dark 207 37 - Adaptation to Non-Zero Luminance Fields 208 38. The General Courseof Light Adaptation 209 39. Immediate Responsesto Illumination Transientsin the Dark-Adapted Eye 21 0 40. Instantaneous Thresholdof the Eye 211 41. Operating Characteristics Produced by Different Levels of Light Adaptation 212 42 The Perceptionof Acuity Targets by the Dark- Adapted Eye After Exposure to Brief Flashesof Light 43. Dark-Adaptation as a Functionof Pre-Exposure Intensity 44. Dark-Adaptation as a Functionof Pre-Exposure Duration 45. Equivalent Steady State Adaptation Levels After Exposure to Short Duration Illumination 216 46. Luminance Thresholds for Different AcuitiesDur- ing Dark-Adaptation 47. Luminance Thresholds for Different Acuities After One Secondof Dark-Adaptation 218 48. Dark-Adaptation Measured by Test Flashesof Dif- ferent Wavelengths 49. Threshold Target Angular Size as a Functionof Contrast Ratio and Background Luminance 220 X , Figure Page 50 Luminance Threshold for Visibilityand Discri- mination of Motion as a Functionof Stimulus Speed 221 51. The Upper Speed Threshold as a Functionof Luminance 2.22 52 0 Threshold Luminance as a Functionof Speed 223 53. Isochronal Threshold Velocityas a Function of Dur- ation of Exposure with Luminance as a Parameter 224 54 - Isochronal Threshold Velocityas a Functionof Lum- inance with Durationof Exposure as a Parameter 55. Time to Identia a Moving Point as Functionof Rrte of Motion, Directionof Motion and Presenceof Reference Points 226 56. Energy Required for the Visibilityof a Moving Test Spot as a Functionof its Exposure Time 227 57 * Threshold Velocity asa Function of Practice with Duration of Exposure, Luminance, and Reference Points as Parameters 228 58. The Differential Angular Speed Threshold(A U) as a Functionof Angular Speed(u) 59. The Weber Ratio(AU/U) as a Functionof Angular Speed for Discriminating Adjacent, Separate and Superimposed Stimuli 60. The Instantaneous Threshold for elocity 61. Dynamic Visual Acuity as a Functionof the Angular Velocityof the Test Ojbect 62. The Effectof