JSC-13864 SPACE SHUTTLE ORBITER APPROACH AND LANDING TEST FINAL EVALUATION REPORT PREPARED BY Approach and Landing Test Evaluation Team APPROVED BY Aaron Cohen Manager, Orbiter Project Manager, Approach and LanW ing Test NATIONAL AERONAUTICS AND SPACE ADMINISTRATION LYNDON B. JOHNSON SPACE CENTER HOUSTON, TEXAS February 1978 \ i ' CONTENTS Section Page 1.0 INTRODUCTION .......................... 1-1 2.0 CAPTIVE-INERT TEST PHASE .................... 2-1 2.1 TAXI TESTS ........................ 2-1 2.2 FLIGHT TEST PROGRAM .................... 2-1 2.3 PERFORMANCE ASSESSMENT .................. 2-1 3.0 CAPTIVE-ACTIVE TEST PHASE ................... 3-1 3.1 FLIGHT TEST PROGRAM .................... 3-1 3.2 PERFORMANCE ASSESSMENT .................. 3-1 4.0 FREE F'LIGHT TEST PHASE ..................... 4-1 4.1 FLIGHT TEST PROGRAM .................... 4-1 4.1.1 Free Flight 1 ................... 4-3 4.1.2 Free Flight 2 ................... 4-5 4.1.3 Free Flight 3 ................... 4-7 4.1.4 Free Flight 4 ................... 4-9 4.1.5 Free Flight 5 ................... 4-11 4.2 ORBITER PERFORMANCE ASSESSMENT .............. 4-13 4.2.1 Structures .................... 4-13 4.2.2 Mechanical Systems ................ 4-16 4.2.3 Power ....................... 4-26 4.2.4 Pyrotechnics ................... 4-29 4.2.5 Avionics ..................... 4-29 4.2.6 Environmental Control and Life Support System ... 4-37 4.2.7 Aerodynamics ................... 4-37 4.2.8 Government-Furnished Equipment .......... 4-47 iii Section Page 4.3 PILOT'S REPORTS ...................... 4-59 4.3.1 Free Flight 1 ................... 4-59 4.3.2 Free Flight 2 ................... 4-64 4.3.3 Free Flight 3 ................... 4-70 4.3.4' Free Flight 4 ................... 4-74 4.3.5 Free Flight 5 ................... 4-79 4.4 FLIGHT 5 APPROACH AND LANDING ASSESSMENT ......... 4-89 4.5 FLIGHT TEST REQUIREPlENTS ASSESSMENT ............ 4-91 5.0 FLIGHT OPERATIONS ASSESSMENT .................. 5-1 5.1 TRAINING AND SII!J~ULATIONS ................. 5-1 5.2 ONBOARD SYSTEMS ...................... 5-1 5.2 .I Software Flexibility ............... 5-1 5.2.2 Ground Monitoring Concept ............. 5-1 5.2.3 Redundancy Management .......- ........ 5-1 5.2.4 Redundancy Management Switches .......... 5-2 5.3 GROUND SYSTEMS ...................... 6-1 7.0 ANOMALY SUMMARY ........................ 7-1 7.1 CAPTIVE-ACTIVE FLIGHTS .................. 7-1 7.1.1 Hydraulic System 1Water Boiler Steam Vent Line Temperature Reading Was Low. ..... 7-1 7.1.2 Inertial Measurement Unit 1 Would Not Go To Operate ................... 7-1 7.1.3 Nose Landing Gear Door Thruster Triggering Pawl Did Not Function .............. 7-2 7.1.4 Auxiliary Power Unit 1 Exhaust Duct Temperature Measurement Failed ......... 7-2 iv I Section Page 7.2 FREE FLIGHTS ....................... 7-5 7.2.1 General Purpose Computer 2 Lost Synchronization at Separation .................. 7-5 7.2.2 Equivalent Airspeed "Off" Flag Was Reported On Commander's AlphalMach Indicator During Free Flight 1 .................. 7-7 7.2.3 Main Landing Gear Door Hinge Pin Assembly WasMissing. .................. 7-7 7.2.4 Orbiter UHF Communications Were Marginal and Noisy on Channel 259.7 Megahertz ........ 7-8 7.2.5 OPS 203, OPS ITEM 13 and OPS 201 Error Messages . 7-8 7.2.6 Orbiter Pilot's Intercommunications Were Intermittent .................. 7-12 7.2.7 Fuel Cell 1 Condenser Exit Temperature Was Low . 7-12 7.2.8 Orbiter Landing Gear "Chattered" During Hard Braking.. ................... 7-15 7.2.9 Centerline Camera Activated Prematurely ...... 7-16 7.2.10 Maintenance Recorder Tracks 8 Through 14 and "Bulk Erase" Were Inoperative ........ 7-16 7.2.11 Left Main Landing Gear Brake Lining and Heat Sink Were Damaged ............. 7-17 % '7.2.12 Inertial Measurement Unit 1 Y-Axis Accelerometer Calibration Was Out of Tolerance ........ 7-17 7.2.13 TACAN Failures To Lock .............. 7-17 7,2,.14 Auxiliary Power Unit 3 Exhaust Duct Temperature Measurement Failed ......... 7-18 7.2.15 Main Landing Gear Camera 1 Film Had Torn Sprocket Holes ................. 7-18 7.2.16 Carrier Aircraft Aft Camera Failed To Transport Film ................. 7-18 7.2.17 Hydraulic System 3 Pressure Was Low During Postlanding Load Test .............. 7-20 V Section Page 8.0 CONCLUSIONS AND RECOMMENDATIONS ................ 8-1 9.0 REFERENCES.. ......................... 9-1 APPENDIX A - VEHICLE DESCRIPTION .................. A-1 APPENDIX B - VEZICLE HISTORICAL DATA ................ B-1 APPENDIX C - CAPTIVE-INERT AND CAPTIVE-ACTIVE FLIGHT DESCRIPTIONS . c-1 APPENDIX D - VEHICLE MASS PROPERTIES ................ D-1 APPENDIX E - FLIGHT TEST REQUIREMENTS SUMMARY ............ E-1 APPENDIX F - METEOROLOGICAL DATA .................. F-1 APPENDIX G - PROBLEM SUMMARY .................... G-1 vi 1.0 INTRODUCTION The Approach and Landing Test Program consisted of a series of steps leading to the demonstration of the capability of the Space Shuttle orbiter to safely approach and land under conditions similar to those planned for the final phases of an orbital flight. The tests were conducted with the orbiter mounted on top of a specially modified carrier aircraft (fig. 1-1). The first step, completed January 10, 1977, provided airworthiness and per- formance verification of the carrier aircraft after modification. The second step, completed on March 2, 1977, consisted of three taxi tests and five flight tests with an inert unmanned orbiter. The third step, completed on July 26, 1977, consisted of three mated tests with an active manned orbiter. The fourth step, completed Octaber 26, 1977, consisted of five flights in which the or- biter was separated from the carrier aircraft. For the final two flights, the orbiter tail cone, which had been used to reduce buffeting effects, was re- placed by dummy main engines to simulate the actual orbital configuration. Landing gear braking and steering tests were accomplished during rollouts fol- lowing the free flight landings. Ferry testing was integrated into the Approach and Landing Test Program to the extent possible. In addition, four ferry test flights were conducted with the orbiter mated to the carrier aircraft in the ferry configuration after the free-flight tests were completed. The primary objectives of the program were as follows. a. Verify orbiter subsonic airworthiness, integrated systems operations and selected subsystems operation for First Orbital Flight. b. Verify an orbiter pilot-guided approach and landing capability. c. Verify an orbiter subsonic automatic terminal area energy management/ automatic landing capability. d. Verify an orbiter capability to safely approach and land in selected gross weight/center of gravity configurations within the operational envelope. These objectives were accomplished by flying well within the flight envelope and extrapolating the results to the limits of the flight envelope. References 1 and 2 contain the results of the postflight evaluations of the captive-inert and captive-active flights. Reference 3 contains the results of the ferry flight testing. In general, this report contains only the results of the postflight evaluation of the free flights. However, summaries of Infor- mation contained in references 1 and 2 have been included. Descriptions of the test vehicle, Enterprise (Orbiter 101), and the Shuttle carrier aircraft are given in appendix A. Vehicle historical information is given in'appendix B. Greenwich mean time (G.m.t.) is used in this report and elapsed flight time is referenced to carrier aircraft brake release. Unless otherwise noted, altitudes have been determined from C-band radar data and are referenced to mean sea level (MSL). All tests were conducted at Edwards Air Force Base, California. 1-1 1-2 2.0 CAPTIVE-INERT TEST PHASE 2.1 TAXI TESTS Test plans called for three taxi runs to be made at progressively higher speeds to evaluate handling qualities of the mated carrier aircraft/orbiter and obtain engineering data prior to the first captive flight. Specific objectives were to evaluate the technique of setting thrust for takeoff, directional stability and control, elevator effectiveness, pitch response, thrust reverser effective- ness, and airframe buffet. The three runs were successfully accomplished on February 15, 1977, at maximum speeds of 78, 122 and 137 knots. No areas of concern were identified that prevented proceeding with the first flight of the mated carrier aircraft/orbiter. Details of the test conditions and results are given in reference 1. 2.2 FLIGHT TEST PROGRAM Areas requiring flight data prior to the initiation of the captive-inert flight testing included (1) the definition of the flight envelope boundary based on adequate flutter margin, empennage loads (vertical tail, horizontal tail, and tip fins) during maneuvering flight, mated configuration buffet, and the effects of a carrier aircraftlorbiter longitudinal trim modification; (2) verification of the interface loads and corresponding flight conditions to ensure a positive launch separation; and (3) verification that a launch abort maneuver could be performed within the orbiter 75-percent wing load design criteria boundary. Five captive flights were conducted with an inert unmanned orbiter to satisfy these requirements. The first four flights were conducted to evaluate the air- worthiness of the mated configuration and to establish the operational flight envelope for the captive-active and launch phases of the Approach and Landing Test Program. The purpose of the fifth flight was to evaluate mated perfonn- ance