NASA SP-4002 PROJECT GEMINI TECHNOLOGY AND OPERATIONS Prepared by James M. Grimwood and Barton C. Hacker with Peter J. Vorzimmer THE NASA HISTORICAL SERIES ___.,/ Scientific and Technical Information Division '___7 OFFICE OF TECHNOLOGY UTILIZATION 1969 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Washington, D.C. For sale by the Superintendent of Documents U.S. Government Printing Office, Washington, D.C. 20402 Price $2.75 (paper cover) Librm'j o_ C._'¢ss Catalog Card Number 68-62086 FOREWORD Gemini was one of the early pioneering efforts in the developing space capability of this nation. The initiation of this program was timed to take advantage of the knowledge gained in our first series of manned space flights-- Project Mercury. The Mercury program successfully demonstrated manned orbital flight. Perhaps more important it provided extensive information on how to build and fly spacecraft for the more complex missions yet to come. Drawing on this experience, the Gemini program was able to produce for its time a highly flexible space vehicle of considerable operational capability. These characteristics enabled a rapid expansion of American flight horizons. The most significant achievements of Gemini involved precision maneuver- ing in orbit and a major extension of the duration of manned space flights. These included the first rendezvous in orbit of one spacecraft with another and the docking of two spacecraft together. The docking operation allowed the use of a large propulsion system to carry men to gre_ter heights above Earth than had been previously possible, thereby enabling the astronauts to view and photograph Earth over extensive areas. Precision maneuvering was also employed during the very high speed reentry back to the surface of Earth, enabling accurate landings to be made. The length of our manned space flights was extended to as long as 14 days, a duration that has yet to be exceeded as of this writing, although this was accomplished about three years ago. Of great general interest were the investigations of the operations of an astronaut outside the confines of his spacecraft, protected from the hard vac- uum of space by his pressurized space suit. These extravehicular activities did in f_t produce some difficulties, but, in the end, highly successful operations were conducted. All of these activities have greatly contributed to expanding activities in space that we now have underway or will be forthcoming. In Apollo, the pro- gram involved with landing men on the lunar surface, the crews must be trans- ported roughly 0_40,000 miles to the Moon and then back to Earth. This trip will take a week or more. The Apollo spacecraft must perform a rendezvous not near Earth but out at lunar distances in order for this mission to be success- ful. Once again, the astronauts must leave their spacecraft and s in their pressure suits, step out onto the lunar surface so that scientific exploration can be con- ducted. The fact that all of these things were initially demonstrated and then investigated further in a number of the Gemini missions greatly aids the devel- opment of the more difficult missions that we are about to undertake. Perhaps the most significant aspect of the Gemini program was the man- ner in which the astronauts contributed to the success of each mission. In the flying of the spacecraft, in the management of the systems, in the overcoming of problems_ and in the aid to attainment of important scientific and technologi- cal information, their presence enhanced greatly the success of the program. v PROJECT GEMINI: A CIIRONOLOGY They were backed up by a large and dedicated team of people here on the ground who designed, developed, and checked out the vehicles and controlled the flights. The Chronology presented herein as a factual presentation of events taken primarily from official documentation of the program. It, therefore_ cannot reflect many of the "behind the scenes" activities so important to the con- duct of a successful program involving exploratory endeavors. The high moti- vation to make the Gemini program work, file rapid reaction in overcoming dif- ficulties, 1,_rge and small, and the attention to detail are all factors contributing to the ten successful manned flights which provided nearly two thousand man hours of direct space flight experience. CtIARLES W. MATHEWS Deputy Associate Administrator O_ce of Manned Space Flight September 16, 1968 vi CONTENTS PAGE LIST OF ILLUSTRATIONS .................................... viii INTRODUCTION .............................................. xiii PART I--CONCEPT AND DESIGN ............................ 1 PART II--DEVELOPMENT AND QUALIFICATION ............ 69 PART III--FLIGHT TESTS .................................... 173 APPENDICES ................................................. 263 i. GEMINI PROGRAM FLIGHT SUMMARY DATA ................... 264 TABLE A: General...................................... 264 TABLE B: OrbitalOperations............................. 266 TABLE C: ProjectGemini Experiments.................... 268 TABLE D: ExtravehicularActivityon Gemini Missions...... 270 2. GEMINI PROGRAM AND MISSION OBJECTIVES .................. 271 3. VEHICLE MANUFACTURING AND TESTING HISTORIES ........... 277 TABLE A: Gemini Launch Vehicle........................ 277 TABLE B: Gemini Target Vehicle......................... 279 TABLE C: Gemini Target Launch Vehicle.................. 280 TABLE D: Gemini Spacecraft............................. 281 4. WORLDWIDE TRACKING NETWORK ........................... 282 5. COST OF GEMINI PROGRAM................................. 283 6. NASA CENTERS AND OTHER GOVERNMENT AGENCIES PARTICI- PATING IN THE GEMINI PROGRAM ............................ 283 7. CONTRACTORS, SUBCONTRACTORS, AND VENDORS ............... 284 8. U.S. MANNED SPACE FLIGHT RECORD, SUMMARY OF MERCURY AND GEMINI FLIGHTS ...................................... 290 INDEX ........................................................ 291 vii LIST OF ILLUSTRATIONS FIGURE PAGE Frontispiece First successful rendezvous .................................. ii 1 Proposed mission for modified Mercury capsule ................ 3 2 Early version of "lifting" Mercury capsule .................... 5 3 Proposed version of one-man space station ..................... 6 4 Orbital operations requiring a rendezvous development program__ 8 5 Deployment sequence for Mercury paraglider ................... 9 6 Interior arrangement for proposed two-man Mercury spacecraft__ 10 7 Adapter section of proposed two-man Mercury spacecraft ....... 11 8 Proposed "Lunar Lander" for use with advanced Mercury space- craft: Artist's conception .................................... 12 9 Drawing of modified Titan II for launch of advanced Mercury___ 13 10 Launch schedule for final version of Mark II Project Development Plan ...................................................... 15 11 First publicly released illustration of Gemini spacecraft ......... 2O 12 Operating principle of General Electric fuel cell for Gemini ...... 22 13 Early conception of rendezvous mission ....................... 23 14 Block diagram of Gemini environmental control system ......... 25 15 General arrangement of liquid rocket systems in the Gemini spacecraft and typical thrust chamber assembly ................ 26 16a Gemini flight trainer for crew training ......................... 28 16b Gemini docking trainer for crew training ...................... 28 17 Main elements of the radar rendezvous system on Gemini space- craft and Agena target vehicle ............................... 29 18 Block diagram of the attitude control and maneuvering electronics system of Gemini spacecraft ................................. 29 19 Gemini spacecraft landing gear for land landing with the para- glider ..................................................... 30 20 Ejection scats in the Gemini spacecraft" Artist's conception ...... 31 21 Reactant supply system for Gemini htel cells .................. 33 22 Operation of the horizon sensor for Gemini spacecraft ........... 33 23 Retrograde rocket system for the Gemini spacecraft ............ 34 24 Gemini spacecraft communications system ..................... 35 25 Table showing communiciation functions during a mission ....... 36 26 Inertial guidance system .................................... 37 27 General nomenclature of the Gemini spacecraft ................ 38 28 Gemini spacecraft tracking aids .............................. 39 29 Block diagram of the Gemini spacecraft guidance and control 4O system .................................................... 30 Solid-propellant retrograde rocket motor ...................... 45 31 Parachute recovery system for the first Gemini spacecraft ....... 46 Vlll LIST OF ILLUST_ATI0_S FIGURE PAGE 32 Paraglider deployment sequence of events ..................... 48 33 Emergency parachute recovery system for half-scale paraglider flight test vehicle ........................................... 49 34 "Off-the-pad" escape mode for aborted Gemini mission .......... 50 35 Airborne systems functional test stand at Martin-Baltimore ..... 52 36 Emergency parachute recovery system for full-scale paraglider flight test vehicle ........................................... 54 37 Engineering mockup of Gemini spacecraft at McDonnell, St. Louis ..................................................... 57 38 Proposed layout of Gemini facilities at Cape Canaveral ......... 58 39 Sequence of events for Gemini missions ....................... 59 40 Proposed sequence of events for first Gemini mission