APOLLO TELESCOPE MOUNT THERMAL SYSTEMS UNIT THERMAL VACUUM TEST by H. Fo Trucks, Uwe Hueter, J. H. Wise, mnd F. D. Buchtel George C. Murshull Spuce Flight Center Murshull Spuce Flight Center, Ala 35812 N A T I o N A L A E R o N A u TI cs A N D s PA CE A DM 1 N 1 ST R A TI o N . w A s H I N GT o N, 1. TECH LIBRARY KAFB, NM I llllll IIIII lllll lllll lllll lSll11111 Ill1 1111 0333373 -. REPORT NO. 2. GOVERNMENT ACCESSION NO. 3. RECIPIENT'S CATALOG NO. m 11-6646 NASA- I I. TITLE AND SUBTITLE 5 RFPCiIT DATE March 1972 lpollo Telescope Mount Thermal Systems Unit Thermal ~- Tacuum Test 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT I. F. Trucks , Uwe Hueter, J. H. Wise, and F. D. Bachtel M372 3. PERFORMING ORGANIZATION NAME AN0 ADDRESS 10. WORK UNIT NO. feorge C. Marshall Space Flight Center 11. CONTRACT OR GRANT NO. VIarshall Space Flight Center, Alabama 35812 13. TYPE OF REPORT & PER100 COVEREC .- . ~ ~ ~~ 12. SPONSORING AGENCY NAME AN0 ADDRESS Technical Note qational Aeronautics and Space Administration Yashington, D. C. 20546 -- ~ 14. SPONSORING AGENCY CODE 15. SUPPLEMENTARY NOTES .- 16. -nBSTRACT The Apollo Telescope Mount is a module of the Skylab Orbital Assembly which is designed o expand the knowledge of manned earth-orbital operations and accomplish scientific objectives. ?he Apollo Telescope Mount will be the first manned solar observatory to observe, monitor, and tecord the structure and behavior of the sun outside the earth's atmosphere. The Apollo Tele- cope Mount design also contains the Skylab pointing and attitude control system, a data and com- nunication system, and a solar array/rechargeable battery power system. The Apollo Telescope Mount's Thermal Systems Unit was utilized to conduct a full-scale hermal vacuum test to verify the thermal design and the analytical techniques used to develop the hermal mathematical models. This report discusses thermal vacuum test philosophy, test objec- ives, test configuration, test monitoring, environment simulation, vehicle test performance, and lata correlation. Emphasis is placed on planning and execution of the thermal vacuum test with ,articular attention on problems encountered in conducting a test of this magnitude. - . - ._ 17. KEY WORDS 1 8. Dl STRlBUT1 ON ST AT EMENT I'hermal vacuum test Sun, structure and behavior Skylab Battery power system 19. 2ECURITY CLASSIF. (of this report) 20. SECURITY CLP jlF. (01 thls page) 121. NO. OF PAGES I 22. PRICE Unclassified Unc lassified 74 $3.00 - _..__ I I I For sale by the National Technical Information Service, Springfield, Virginia 22151 NOTICE Because of a waiver initiated and signed in compliance with NASA Policy Directive (NPD) 2220.4, para. 5-b, the International System of Units of measurement has not been used in this document. TABLE OF CONTENTS Page INTRODUCTION .................................. i TESTPLAN ..................................... 4 Test Philosophy ............................... 4 Test Objectives ............................... 5 Test Conditions and Requirements. .................. 6 CONFIGURATION DE SC RJPTION ....................... 9 Flight Vehicle ................................ 9 TSU.. ..................................... 10 Thermal Design. .............................. 12 CHAMBER ...................................... 18 ACE ....................................... 19 Environment Simulators. ......................... 20 ON-SITE THERMAL SUPPORT ........................ 27 Pretest Activity ............................... 27 Test Monitoring. .............................. 27 Post-Test Activity ............................. 29 ORBITAL HEATING SIMULATOR PERFORMANCE ........... 30 Orbital Heating $imulator Calibration ................ 30 Orbital Heating Simulator Test Results ............... 37 VEHICLE TEST PERFORMANCE ....................... 38 Run 2 - Cold Soak ............................. 38 Run 3 - Steady State Extreme Cold Environment ......... 39 Run 4 - Steady State Extreme Cold Environments ........ 39 Run 5 - Transient Extreme Cold Environment. .......... 40 Rvn 6 - Steady State Nominal Hot Environment. .......... 40' Run 7 - Transient Nominal Hot Environment. ........... 40 Run 14 - Liquid TCS Failure ...................... 41 Run 8 - Steady State Extreme Hot Environment .......... 41 Run 9 - Steady State Extreme Hot Environment .......... 41 Run 10 - Transient Extreme Hot Environment. .......... 42 Run 13 - Z Local Vertical ........................ 42 Runs ii and 12 - Pre-Operation and Activation .......... 42 iii TABLE OF CONTENTS (Concluded) Ambient Power -On Test ......................... 43 DATA CORRELATION .............................. 43 Rack Correlation .............................. 44 Canister Correlations ........................... 55 Quadrants ................................... 55 CONCLUSIONS ................................... 61 REFERENCES .................................... 63 iv ~ ..... ~ -.-.--. ....... --.*a----.-,,,,- ....-- .... L IST OF ILLUSTRAT IONS Figure Title Page I. Skylab .................................... i 2 . ATM ..................................... 2 3 . ATMTSU .................................. 3 4 . Typical rack zone ............................ 13 5 . Telescope arrangement ........................ 15 6 . Canister TCS ............................... 16 7 . Testsetup ................................. 18 8 . ACE system schematic ......................... 20 9 . Typical power output waveforms .................. 22 10. Orbital heating simulator control loop ............... 23 li . Calibration radiometer ......................... 26 12 . Correlation factors ........................... 31 13 . Average lamp flux response ..................... 31 14 . Heat flux correlations .......................... 32 15 . Uniformity evolution. radiator normalized flux distributions ............................. 33 16 . Uniformity evolution. rack normalized flux distributions ............................. 34 17 . Heat flux correlation radiator mockup vacuum test ................................ 35 I8. Total zone heat flux control characteristic ............ 36 19 . Calibration profiles .......................... 36 20 . Profile tracking results ........................ 37 21 . Rack component and structure comparisons of empirical temperatures and pretest theoretical tem- peratures for TSU Runs 4 and 9 ................... 45 22 . Rack component and structure comparisons of empirical temperatures and post-test theoretical temperatures for TSU Runs 4 and 9 ......... 46 V LIST OF ILLUSTRATIONS (Concluded) Figure Title Page 23. Rack component and structure comparisons of empirical temperatures and post-test theoretical temperatures for TSU Runs 3, 6, and 9 ...... 47 24. Run 3 distribution of post-test rack model correlations with test data ............................... 48 25. Run 4 distribution of post-test rack model correlations with test data ...................... 49 26. Run 6 distribution of post-test rack model correlations with test data. ...................... 50 27. Run 8 distribution of post-test rack model correlations with test data ...................... 51 28. Run 9 distribution of post-test rack model correlations with test data. ...................... 52 29. Telescopes correlation results .................... 56 30. Comparison of telescope empirical temperatures and pretest theoretical temperatures for TSU Runs 5 and 10 ............................... 57 31. Comparison of telescope empirical tempera- tures and post-test theoretical temperatures for TSU Runs 5 and 10.. ........................ 58 vi LIST OF TABLES Table Title Page i. ATM TSU Test Summary.. ...................... 7 2. ATM TSU Canister Instrumentation ................ ii 3. Telescope Heater Duty Cycles .................... 59 ACKNOWLEDGEMENTS Throughout the Apollo Telescope Mount thermal systems unit test program, SkE-ASTN-PTA received valuable assistance from the Martin- Marietta Corporation, ATM Thermal Unit, supervised by Lawrence D. Lancaster, and the Brown Engineering Company, Inc. , Thermal Engineering Section, supervised by J. J. Urbanski. In addition, all data analysis presented in this report was performed by these contractor personnel except analyses pertaining to the environmental simulation. S&E-ASTN-PTA gratefully ac- knowledges the valuable support of Mr. James McLane and the Space Environ- ment Simulation Laboratory for providing overall direction of the thermal vacuum test facility. vii I DEFINITION OF SYMBOLS Svmbol Definition Ha-1 Harvard College Observatory hydrogen alpha Ha-2 Apollo Telescope Mount hydrogen alpha a! Infrared absorptivity a! Solar absorptivity S A Delta (change) E Emissivity Stefan-Boltzmann constant MethanolfWater viii I APOLLO TELESCOPE MOUNT THERMAL SYSTEMS UNIT THERMAL VACUUM TEST I NTRODUCTJ ON The Apollo Telescope Mount (ATM) is part of the Skylab, an earth- orbiting space station, scheduled to be launched by the National Aeronautics and Space Administration (NASA) in 1973. The Skylab (Fig. i) includes the Saturn V Workshop, the Command Service Module (CSM) , the Multiple Dock- ing Adapter (MDA) , the Airlock Module (AM), and the ATM. The Skylab pro- grams intend to perform scientific investigations in earth orbit, to study long- duration space flight effects on men and systems, and to collect information useful for future space programs. The ATM mission objective is to observe the sun outside the earth's atmosphere. High-resolution observations of the solar disc will provide data in the visible, ultraviolet, and X-ray