Experiments for GT-4 Mission

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Program Gemini Working Paper No. 5023____ _ -_-- - - -- __I___ ----- -- - -FOB GT-4 N75-70130'.

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0019%- 17358- - -

EXPERIMENTS FOR G T - 4 MISSION

DISTRIBUTION AND REFERENCING'Thispaper is not suitable for general distribution or referencing, It may be referencedonly in other working correspondence and documents by participating 'organizations.

.NATIONAL AERONAUTICS AND SPACE ADMNSX"X'ATIONMANNED SPACECRAFT CENTER

HOUSTON, TEXASMay 14, 1965


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NASA Program Gemini Working Paper No. 5023

EXPERIMENTS FOR GT-U MISSION

Prepared by: 6L47*-rS6- .Gordon C. HrabalAST, Experiments Office

Authorized for Distribution:

Charles W. MathewsManager, Gemini Program Office

NATIONAL AERONAUTICS AND SPACE ADMINISTRATIONMANNED SPACECRAFT CENTER

HOUSTON, TEXASMay 14, 1965


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CONTENTSSection Page1.0 INTRODUCTION 1-12.0 POSTFLIGHT EVALUATION REPORTING . . . . 2-13. 0 EXPERIMENT NUMBER D-l - BASIC OBJECT PHOTOGRAPHY ANDEXPERIMENT NUMBER D-6 - SURFACE PHOTOGRAPHY ...... 3-1

J.I Objective 3-13.2 Justification 3-13.3 Scope 3-2

3.3.1 Experiment D-l 3-23.3.2 Experiment D-6 3-23.4 Experiment Equipment Description 3-2

3.4.1 Camera 3-33. .2 Camera film back 3-33.^.3 Questar l400-mm lens 3-33.4.4 Nikkor 200-mm lens 3-43.4.5 Telescope sight 3-53-4.6 Periscope viewer . 3-53.4.7 Optical mounting bracket 3-53-4.8 Window mount 3-53.4.9 Film transport adapter 3-53-5 Spacecraft Operational Equipment 3-6

3-5.1 Photo event indicator 3-63.5.2 Gemini voice recorder 3-63.5-3 Optical sight 3-63-6 Operational Description 3-6

3 - 6.1 Unstow equipment 3-63-6.2 Mount equipment 3-63.6.3 Object acquisition 3-73.6.4 Photograph object 3-73.7 Preflight Considerations 3-8


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Section PageJ.7-1 Equipment 3-83.7.2 Personnel 3-8

3.8 Inflight Considerations 3-83.8.1 Flight plan 3-93.8.2 Equipment preparation procedures .... 3-93.8.3 Photographic correlation 3-93.8.4 Focus and/or object definitionproblems Qaestar lens 3-103.8.5 Focus and/or object definitionproblems Nikkor 200-mm lens 3-H

3-9 Postflight Considerations 3-113.9-1 Experiment equipment retrieval 3-113.9-2 Other required data 3-H3 - 9 - 3 Postflight debriefing 3-11

3.10 Installation Procedures 3-113-11 Equipment Checkout Procedures 3-12

3.11.1 Preinstallation acceptance 3-123.11.2 Alinement 3-123.11.3 Resolution . 3-12

3.12 Flight Qualification Requirements 3-124.0 EXPERIMENT NUMBER D-8 - RADIATION INSPACECRAFT . . . . 4-1

4.1 Objective 4-14.2 Justification 4-14.3 Scope4.4 Experiment Equipment Description 4-2

4.4.1 Active dose rate indicators 4-24.4.2 Passive dosimeters 4-34.5 Operational Description 4-3


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Section .Page4.5.1 Active dose rate indicator -Type I 4-34.5.2 Active dose rate indicator -

T!ype V 4-4i t - , 5 - 3 Passive dosimeters 4-4

4.6 Preflight Considerations 4-44.6.1 Equipment calibration 4-44.6.2 Equipment preflight servicing . . . 4-44.6.3 Personnel . 4-5

4.7 Inflight Considerations 4-54.7.1 Flight plan 4-54.7.2 Reporting requirements 4-5

4.8 Postflight Considerations 4-64.8.1 Experiment equipment retrieval . . . 4-64.8.2 Data requirements . . . 4-64.8.3 Postflight debriefing 4-7

4.9 Installation Procedures 4-74.9.1 Active dose rate indicators. .... 4-74.9.2 Passive dosimeters 4-7

4.10 Equipment Calibration Procedures 4-84.10.1 Active dose rate indicators .... 4-84.10.2 Passive dosimeters 4-8

4.11 Flight Qualification Requirements 4-85.0 EXPERIMENT NUMBER D-9 - SIMPLE NAVIGATION 5-1

5.1 Objective 5-15.2 Justification 5-15.3 Scope 5-2


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VI

Section

6.0

5>

5 - 5

5.6

5.7

5.8

5 - 9

5.105-115.12

Experiment Equipment Description5A.1 Space stadimeter5. .2 Space sextantPrincipals of Operation5.5.1 Space stadimeter5.5.2 Space sextantOperational Description5-6.1 Space stadimeter5.6.2 Space sextantPreflight Considerations ...5.7.1 Equipment5.7.2 PersonnelInflight Considerations5.8.1 Flight plan5.8.2 Operational requirementsPostf light Considerations .... .5.9.1 Experiment equipment retrieval . . .5.9.2 Data requirements5.9.3 Postf light debriefingInstallation ProceduresEquipment Checkout ProceduresFlight Qualification Requirements

EXPERIMENT NUMBER M-3 - INFLIGHT EXERCISER6.16.26.3

ObjectiveJustificationScope

Page5-35-35-35-35-5-55-55-65-85-95-95-95-95-95-95-105-105-105-115-115-115-116-16-16-16-1


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Section6.46.56.6

6.76.8

6.96.106.11

Experiment Equipment DescriptionOperational Description ...Pre flight Considerations6. 6. 1 Equipment6. 6. 2 PersonnelInflight ConsiderationsPostflight Considerations6. 8. 1 Experiment equipment retrieval . . .6. 8. 2 Data requirements6.8.3 Postflight debriefingInstallation ProceduresEquipment Checkout ProceduresFlight Qualification Requirements

7.0 EXPERIMENT NUMBER M-4 - INFLIGHT EHONOCARDIOGRAM . .7.17-27-37A7-57-6

7-77-8

ObjectiveJustificationScopeExperiment Equipment DescriptionOperational DescriptionPref light Considerations7. 6. 1 Equipment7-6.2 PersonnelInflight ConsiderationsPostflight Considerations

Page6-26-26-26-26-36-36-36-3' 6 - 46-46-46-46-47-17-17-17-17-17-27-27-27-27-37-3


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Section Page

8.0

9.0

7.97.107.11

7. 8. 1 Experiment equipment retrieval . . .7. 8. 2 Data requirements7.8.3 Postf light debriefingInstallation Procedures . .Equipment Checkout ProceduresFlight Qualification Requirements

EXPERIMENT NUMBER M-6 - BONE DEMINERALIZATION . . .8.18.28.38.4

8.58.6

8.78.88.98.108.11

ObjectiveJustificationScopeExperiment Techniques and Equipment8. U.I . Techniques8.4.2 EquipmentOperational DescriptionPreflight Considerations '.8.6.1 Launch site8.6.2 Recovery areasInflight RequirementsPostflight ConsiderationsInstallation ProceduresEquipment Checkout ProceduresFlight Qualification Requirements

EXPERIMENT NUMBER MSC-1 - ELECTROSTATIC CHARGE . . .9-19.2

ObjectiveJustification

7-37-37-37-37-47-48-18-18-18-18-28-28-28-28-28-28-38-38-38-48-48-49-19-19-1


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Section Page9.3 Scope 9-19-^ Experiment Equipment Description 9_29-5 Operational Description 9_29-6 Preflight Considerations 9_2

9.6.1 Equipment 9-29.6.2 Personnel 9-59-7 Inflight Considerations 9-39.8 Postflight Considerations 9-U

9 - 8.1 Experiment equipment retrieval . . . 9- -9- 8.2 Data requirements 9-U9.8.3 Postflight debriefing 9-U

9.9 Installation Procedures 9-59.10 Equipment Checkout Procedures 9-59.11 Flight Qualification Requirements 9-5

10. 0 EXPERIMENT NUMBER MSC-2 - PROTON - ELECTRONSPECTROMETER 10-110.1 Objective 10-110.2 Justification 10-110.3 Scope 10-110.k Experiment Equipment Description 10-210.5 Operational Description 10-210.6 Preflight Considerations 10-3

10.6.1 Equipment 10-310.6.2 Personnel 10-310.7 Inflight Considerations 10-3


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X

Section

10.8 Postf light Considerations10. 8. 1 Experiment equipment retrieval . . . 10-410.8.2 Data requirements ......... 10-410.8.3 Postflight debriefing ....... 10-4

10. 9 Installation Procedures ........ ... 10-410.10 Equipment Checkout Procedures ........ 10-410. 11 Flight Qualification Requirements ...... 10-4

11.0 EXPERIMENT NUMBER MSC-3-TRI-AXISMAGNETOMETER .................... 11-111.1 Objective .................. 11-111.2 Justification ................ 11-111.3 Scope .................... 11-111. 4 Experiment Equipment Description ...... 11-211.5 Operational Description ........... 11-211. 6 Pref light Considerations .......... 11-3

11.6.1 Equipment ............. 11-311.6.2 Personnel .... ......... 11-311.7 Inflight Considerations ........... 11-311.8 Postflight Considerations . ......... 11-3

11. 8. 1 Experiment equipment retrieval . . . 11-311.8.2 Data requirements ......... 11-411.8.3 Postflight debriefing ....... 11-4

11.9 Installation Procedures ........... 11-411.10 Equipment Checkout Procedures ........ 11-411.11 Flight Qualification Requirements ...... 11-4


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XI

Section Page12.0 EXPERIMENT NUMBER MSC 10 - TWO-COLOR EARTH'S

13.0

LIMB PHOTOS12.1 Objective12.2 Justification12.3 Scope12. U Experiment Equipment Description12.5 Operational Description12.6 Preflight Considerations

12.6.1 Equipment12.6.2 Personnel

12.7 Inflight Considerations12.8 Postf light Considerations .

12.8.1 Experiment equipment retrieval . . .12.8.2 Data requirements12.8.3 Postf light debriefing

12.9 Installation Procedures12.10 Equipment Checkout Procedures12.11 Flight Qualification RequirementsEXPERIMENT NUMBER S-5 - SYNOPTIC TERRAIN PHOTOGRAPHY/AND EXPERIMENT NUMBER S-6 - SYNOPTIC WEATHERPHOTOGRAPHY

. 13.1 Objective13.2 Justification ...13.3 Scope

13.3.1 Experiment S-513.3.2 Experiment S-6

12-112-112-112-112-212-212-212-212-312-312-U12-1).12-U12-512-512-512-5

13-113-113-113-213-213-2


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Section . Page13. Experiment Equipment Description 13-213.5 Operational Description 13-3

13.5.1 Experiment S-5 13-313.5.2 Experiment S-6 13-313.6 Preflight Considerations 13Jj.

13.6.1 Equipment 1J-U13.6.2 Personnel 13-U13.7 Inflight Considerations 13-513.8 Postflight Considerations 13-6

13.8.1 Experiment equipment retrieval ... 13-613.8.2 Data requirements 13-613.8.3 Postflight debriefing 13-613.9 Installation Procedures 13-613.10 Equipment Checkout Procedures 13-713.11 Flight Qualification Requirements 13-7


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LIST OF TABLES

Table Page1-1 EXPERIMENTS FOR GT-4 1-23-1 LIST OF MAJOR EQUIPMENT COMPONENTS 3-13U-I LIST OF EXPERIMENT D-8 EQUIPMENT 4-9


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LIST OF FIGURESFigure Page3-1 Experiment major equipment components 3-l43-2 Spacecraft main stowage area and inflightassembled position for experiment equipment . . . . 3-153-3 Experiment stowage containers . . . . . . . . . . . . 3-163-4 Spacecraft operational equipment 3-1?3-5 Assembled questar lens-camera combination 3-183-6 Assembled questar lens-camera combination in use. . . 3-193-7 Assembled experiment equipment components 3-204-1 Fixed active dose rate indicator Type I 4-i.O4-2 Removable active dose rate indicator Type V .... 4-114-3 Passive dosimeter 4-12:4-4 Experiment equipment spacecraft installation

location 4-134-5 Experiment electrical block diagram 4-l44-6 Experiment electrical schematic 4-154-7 Radiation-sensitive head in use by the pilot . . .. 4-165-1 Space Stadimeter. 5-125-2 Space sextant 5-135-3 Theory of space navigation principals . . . . . . . . 5-1 -5-4 Space stadimeter in operation by astronaut 5-155-5 Orbital observation sequence positions 5-166-1 Inflight exerciser 6-56-2 Inflight exerciser major components 6-6


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Figure Page6-3 Inflight exerciser and. spacecraft stowage

6-1*7-17-27-39-19-2

Inflight exerciser in use by astronaut . . . . . .Inflight phonocardiogram equipment components . . .GT-4 biomedical and communications harness ....GT-U biomedical and communications harnessfitted to a subject

Electrostatic charge equipment componentsElectrostatic charge equipment spacecraftretro-adanter location

6-76-87'57-67-7i i .9-6

9-710-1 Proton-electron spectrometer (experiment MSC-2)

and tri-axis flux-gate magnetometer(experiment MSC-j) assembly 10-5

10-2 Experiments MSC-2 and MSC-3 equipmentspacecraft adapter location 10-6

12-1 Hasselblad camera film magazine ..... 12-612-2 Hasselblad camera with photo event indicator . . . 12-712-3 Horizon view for desired photographs 12-812-4 Variation of sunlight scattering angle during

nine groups of photographs 12-8


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1-1

1.0 INTRODUCTION

A variety of scientific, medical, technological, and engineeringexperiments will be conducted on the Gemini Program missions to extendman's knowledge of space and to further develop the ability to sustainlife in the space environment.This document presents detailed information concerning thethirteen experiments to be conducted on the Gemini (GT)-4 mission.These experiments are.listed in table 1-1. Some experiments have been

combined for description purposes due to similar objectives or use ofthe same equipment.This document describes the experiments and the requirements andresponsibilities necessary for the successful accomplishment of theirobjectives. It is to be used for informational purposes only, but maybe used as a reference and for planning additional experiments on futurespace flights. It will be updated when necessary to reflect significantchanges in the equipment, procedures, or details of the experiments.


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TABLE 1-1.- EXPERIMENTS FOR

Experimentnumber Experiment titleD-lD-6D-8D-9M-5N-kM-6MSC-1MSC-2MSC-3MSC-10S-5S-6

Basic Object PhotographySurface PhotographyRadiation in SpacecraftSimple NavigationInflight ExerciserInflight PhonocardiogramBone DemineralizationElectrostatic ChargeProton-Electron SpectrometerTri-Axis MagnetometerTwo-Color Earth's Limb 'Photosf .Synoptic Terrain PhotographySynoptic Weather Photography


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2.0 POSTFLIGHT EVALUATION REPORTING

The thirteen experiments will be conducted essentially as describedin this document. The preflight, inflight, and postflight proceduresare included to the point that the experimental equipment or data is re-turned to the conducting organizations for evaluation. These organiza-tions are responsible for performing the postflight evaluation and forproviding detailed reports of .the results obtained. If possible, thesereports should be completed in time to be included in section 8 of theGemini Program Mission Report for the GT- Mission. If the evaluationof any experiment has not been completed within the 30-day time limitestablished for publication of the mission report, a preliminary reportwill be submitted to meet this deadline. For all such experiments, thecomplete, detailed results of the experiment will be reported later inthe form of a supplemental report to the basic mission report. Supple-mental report numbers will be assigned when this requirement becomesnecessary. For more information on preparation of the basic or supple-mental reports, refer to Gemini Working Paper No. 5008 and Supplement Dthereto.


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3-1

J.O EXPERIMENT NUMBER D-l - BASIC OBJECT PHOTOGRAPHYAND EXPERIMENT NUMBER D-6 - SURFACE PHOTOGRAPHY

3.1 ObjectiveThe objective of Experiments D-l and D-6 is to investigate thetechnical problems associated with observing, evaluating, and photo-graphing space-borne and terrestrial objects from an orbiting space-craft. They will also evaluate man's ability to maintain object-cameraorientation by maneuvering the spacecraft. Within the limits of theGemini spacecraft, photo-optical equipment will be employed by theastronauts to determine man's ability to acquire, track, and photographselected objects. The data obtained will be of great value in estab-lishing design criteria for future manned photographic/observation spacemissions.

3.2 JustificationPrevious attempts to photograph objects from manned spacecraftindicate that man has the potential to acquire, track, and photographselected objects. Some advantages of utilizing man to perform a

photographic/observation space mission are as follows:a. The ability to discriminate and decide whether to take aphotograph of a particular object.b. The ability to provide a "quick response" to photograph specialrequests and.objects of opportunity.c. The ability to provide efficient operation with respect tofilm and photographic equipment selection and utilization.d. The capability to "time and position" correlate the photographs

taken without later extensive data reduction.The quantity and quality of information obtained from the photo-optical equipment deployed on a manned spacecraft will give furtherinsight into the contribution of man and the equipment on space photo-graphic missions.Experiments D-l and D-6 have been designed for the Gemini space-craft and complement each other. Experiment D-l is planned to photographspace-borne objects and D-6 will photograph terrestrial objects. They


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3-2

are sponsored by the Photographies Branch, Air Force Avionics Laboratory,Wright-Patterson Air Force Base, Ohio. They are funded through the AirForce Systems Command Field Office located at the NASA Manned SpacecraftCenter, Houston, Texas.

3-3 Scope3-3.1 Experiment D-l.- This experiment is planned to investigatethe technical problems associated with an astronaut's ability to acquire,track, and photograph space-borne objects from an orbiting spacecraft.These objects include natural celestial bodies such as the moon andstars. Each series of objects will require the astronaut to utilizespecific lens-film combinations to take the photographs. The motion

of the space-borne objects with respect to the Gemini spacecraft-mountedcamera/optical system will be compensated for by astronaut maneuveringof the spacecraft to maintain the proper object-camera orientation. Theprimary celestial object for Experiment D-l on the GT-^ mission will bethe moon. Secondary objects are other prominent celestial bodies thatmay be visible during the mission. The astronauts will have a list ofobjects to be photographed at specific times during the mission.3.3.2 Experiment D-6.- This experiment is planned to investigatethe technical problems associated with an astronaut's ability to ac-quire, track, and photograph terrestrial objects from an orbiting space-craft. Each series of objects will require the astronaut to utilize spe-cific lens-film combinations to take the photographs. The motion of theterrestrial objects with respect to the Gemini spacecraft-mounted camera/optical system will be compensated for by astronaut maneuvering of thespacecraft to maintain the proper object-camera orientation. The primaryterrestrial objects for Experiment D-6 on the GT-^ mission will be promi-nent terrestrial features visible from the orbital path. The astronautswill have a list of objects to be photographed at specific times duringthe mission.

3.^ Experiment Equipment DescriptionBoth photographic experiments will be conducted using the samecommercially available photo-optical equipment, modified as necessaryby the McDonnell Aircraft Corporation (MAC) to enable installation andintegration into the Gemini spacecraft. A list of the major equipmentcomponents with their part numbers, weights, and stowage locations isgiven in table 3-1. The experiment major components are illustrated infigure 3-1 and the spacecraft main stowage area and inflight assembledposition are shown in figure 3-2. Some components are stowed separatelyin the spacecraft and some are stowed in the containers illustrated in


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3-3figure 3-3- A detailed description of each of the major components isgiven in the following paragraphs..

3A.I Camera.- The camera is a modified 35-mm Zeiss Contarex-Special incorporating single-lens reflex viewing, a focal plane shutter,lens interchangeability, and interchangeable film backs. Additionalcamera characteristics are as follows.3.4.1.1 Shutter: The camera is equipped with a focal planeshutter which may be adjusted by.the astronaut to provide the followingspeeds: 1/30, l/6o, 1/125, 1/250, 1/500, and 1/1000 seconds. Shutterrelease will be actuated by a flexible cable which is part of the Geminioperational photo event indicator. The shutter is automatically cockedeach time the film is advanced one frame.3.U.I.2 Lens mount; The camera is equipped with a bayonet typelens mount which allows rapid attachment or removal of the two inter-changeable lenses.3.4.1.3 Film advance: The camera is equipped with a modified,single-stroke, film advance lever. The film advance mechanism iscoupled with the shutter mechanism to prevent double exposures. Thisprevents the shutter from being cocked until the film has been advanced.Operation of the film advance lever can be accomplished directly by useof the manual lever or remotely by use of the film transport adapter.3.4.2 Camera film back.- There are three interchangeable filmbacks provided for the camera. An exposure counter is located on thebottom of each film back which couples with the camera film advancemechanism. The counter decreases one digit from 4l each time the filmis advanced one frame. Each film back will hold a standard 35-mm filmcassette having a capacity of approximately 70 exposures using thinbase film. Each film back will contain a different type film to enablethe astronaut to choose a film appropriate to the object being photo-graphed. The type of film to be carried on a particular Gemini mission

will be chosen before launch from one of the following types: Mono-chromatic (SO-206, Panatomic-X 3400>, or Plux-X 3401) J color (AerialEktachrome 8442)j and infrared (Aerial Ektachrome 8443).

3.4.3 Questar l40Q-mm lens.- A Questar lens is provided whichwill attach to the camera bayonet type lens mount. This lens is acom-pact reflecting telescope with a focal length of approximately 56 inches(l4oO mm) and provides coverage of the entire 35-mm (24- by 36-mm) filmformat.3.4.3.1 Filters: Two optical filters are provided with the Que-star lens to reduce image degradation due to blue light scattering onphotographs of terrestrial objects.


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3.4.3.2 Lens characteristics: The Questar lens has a fixedaperture of 3.5 inches vith an axial resolving power of 75 lines permm or greater under laboratory conditions. In the full 35-mm formatconfiguration, the effective apperture is f/l6 and the image magnifi-cation is approximately 28 times. Focusing is accomplished by turninga single control lever on the end of the lens. Focus range is from1 000 feet to infinity with a field-of-view of 1.8 conical angle,exclusive of vignetting. The lens is equipped with a mounting flangeat one end which is compatible with the optical mounting bracket andpermits precise attachment to the spacecraft window frame. The lens,including the camera body extension tube adapter, has an overall lengthof approximately 13 inches and a diameter of approximately 4 inches.3. .4 Nikkor 200-mm lens.- A Nikkor 200-mm lens is provided whichwill attach to the camera bayonet type lens mount.3.4.4.1 Filters: Two optical filters are provided with the Nikkorlens to reduce image degradation due to blue light scattering on photo-graphs of terrestrial objects.3.4.4.2 Lens characteristics; The Nikkor 200-mm lens has anaperture range from f/4.0 to f/22 with a resolution capability of130 lines per mm or greater under laboratory conditions. Change ofaperture is accomplished by turning a movable ring on the lens barrel.In a 35-nim camera system, the image magnification is approximately fourtimes. Focusing is accomplished by means of a movable sleeve on thelens barrel. Focus range is from 20 feet to infinity with a 12 full-angle field-of-view. The lens is equipped with a mounting flange atone end which is compatible with the optical mounting bracket and per-mits precise attachment to the spacecraft window. The lens has anoverall length of approximately 6.5 inches and a diameter of approxi-mately 2.5 inches.3.4.5 Telescope sight.- A telescope sight is provided for use asthe primary viewing and sighting device with the Questar l4oO-mm lens.This sight is an adjustable focus type and provides an image magnifica-tion of approximately 4.25 times with an 8 full-angle field-of-view.

It has a non-illuminated inscribed cross hair and a reticle that corre-sponds to the 1.8 field-of-view of the Questar lens. The sight easilyattaches to the optical mounting bracket to permit viewing through theright-hand spacecraft window. When mounted, the telescope line-of-sightis coincident with the Questar lens within 0.1, and with the spacecraftoptical sight within 0.3. A 2.0 adjustment in both pitch and yaw isprovided to allow boresighting with respect to the spacecraft longitudi-nal axis.


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3-5

3A.6 Periscope viewer.- A periscope reflex viever is providedfor use as the primary viewing and sighting device with the Nikkor200-mm lens.. It will also serve as a .secondary viewer for the Questar1 00-mm lens to investigate the ability of the astronaut to track."an 'object under limited field-of-view conditions (approximately 1.8-). > Thereflex viewer will attach to the ground glass of the reflex camera bodyand extend upward along the attached lens barrel so that"the cameraground glass .can be viewed by the astronaut. ' ' .

3.k.f Optical mounting bracket.- Due to the limited space betweenthe spacecraft window and the astronaut's face, the 35-mm camera systemcannot be used in a direct spacecraft longitudinal alinement. ' The opti-cal mounting bracket is provided to enable the camera optical axis tobe in a near-vertical alinement with respect to the spacecraft axes inorder to utilize the small amount of .cabin space that is available. Thisoptical mounting bracket is securely attached to the window mount (A-frame) for installation on the spacecraft right-hand window frame. Oneend of the optical mounting bracket contains the mechanism for attachingeither the Questar l O-mm or the Nikkor 200-mm lens. It contains asingle-surface mirror, essentially elliptical in shape, .that projects theview seen through the spacecraft window downward through the attachedcamera and lens. The camera will view a reflected image of an objectalong the boresighted line with respect to the spacecraft longitudinalaxis. A mounting is provided on the right side of the optical mountingbracket for precise attachment of the telescope sight.3-^.8 Window mount.- The window mount (A-frame) is provided tomount the optical mounting bracket to the spacecraft right-hand.windowframe. It rigidly mounts to three hard points on the window frame andprovides accurate alinement of the 35-mm camera/optical system with thespacecraft longitudinal axis.3A.9 Film transport adapter.- The film transport adapter (FTA) isprovided to increase the number of exposures that is possible to betaken in a period of time and to ease the astronaut's task. It fastensto the camera manual film transport lever by a quick release typeholder. The operational photo event indicator is used with the FTA toenable one-hand rapid operation of the film advance and shutter release.The film is advanced and the shutter cocked by a squeezing action of theFTA while the thumb operates the shutter by actuating the plunger on thephoto event indicator. Ten photographs may be taken within a 15 secondperiod with minimum degradation of the camera/optical system resolution.


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3-6

3-5 Spacecraft Operational EquipmentIn addition to the 35-nm photo-optical equipment obtained speci-fically for these experiments, certain Gemini spacecraft operationalequipment will be utilized.3.5-1 Photo event indicator.- The operational photo event indica-tor will be connected to the 35-n camera to operate the shutter release.Actuation of the plunger on the photo event indicator will release theshutter and time correlate the exposure through a micro-switch connectedto the spacecraft bi-level channel delayed-time digital tape recorder.The photo event indicator is used with the film transport adapter toenable one-hand operation of the film advance and shutter release. Thephoto event indicator is illustrated in figure 3-^-3.5-2 Gemini voice recorder.- The operational Gemini voice recorderwill be utilized to record any pertinent astronaut remarks during theconduct of these experiments. The voice recorder is illustrated infigure 3-4.3.5-3 Optical sight.- The operational optical sight will bemounted on the spacecraft left-hand window and utilized by the commandpilot for coarse sighting and object acquisition. The optical sight isillustrated in figure 3-4.

3.6 Operational DescriptionThe astronauts will have a detailed flight plan that will list theobjects to be photographed at specific times during the mission. Eachobject series will require use of specific lens-film combinations. Thegeneral operational procedure is as follows:3.6.1 Unstow equipment.- All experimental and operational equip-ment required for these experiments will be stowed at various locationsin the spacecraft. After launch and insertion into orbit, they will;be removed from stowage and assembled in time to track and photographthe first scheduled object-3.6.2 Mount equipment.- The appropriate photo-optical equipmentwill be assembled and mounted to the right-hand window frame for use''bythe pilot. The operational optical sight will be mounted to the left-hand window frame for use by the command pilot in acquiring and tracking

the objects The pilot will mount the window mount/optical mounting bracket,attach the telescope sight and the proper lens, attach the camera with


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3-7the proper interchangeable film back, and position the reflex viewerand other necessary equipment. A visual check-out of the system shallbe completed approximately 5 minutes prior to actuating the camerashutter. The appropriate camera shutter speed and lens aperture settingswill be made for the lens-film- object combination to be photographed.Figure 3-5 is an illustration of the assembled experimental equipmentwith the Questar lens-camera combination.

3.6.3 Object acquisition.- Several modes of object acquisition(coarse and fine) and tracking shall be used at various times duringthese experiments. A "coarse" object acquisition shall be followed bya "fine" acquisition and tracking in preparation for taking the photo-graphs. The nominal procedure is as follows.3.6.3.1 Coarse acquisition visual mode: The command pilot will

acquire the object and maneuver the spacecraft using the Gemini opticalsight mounted on the left-hand window frame.3.6.3.2 Coarse acquisition instrument mode: The command pilotwill maneuver the spacecraft to a predetermined attitude with referenceto the spacecraft attitude instruments. This should aline the objectwithin the field-of-view of the photo-optical system telescope sight.3.6.3.3 Fine acquisition and tracking visual mode: After com-pletion of a coarse object acquisition, the command pilot will continueto maneuver the spacecraft using the optical sight. The pilot willoperate the photo-optical equipment and give verbal directions to the

command pilot while sighting the object through the telescope sight.and/or periscope viewer.3.6.3. Fine acquisition and tracking telescope sight mode:After completion of a coarse object acquisition and the object has beenbrought into the field-of-view of the telescope sight, the command pilotwill transfer the spacecraft attitude control to the pilot. The pilotwill proceed to track the object and maneuver the spacecraft with hisleft hand while operating the photo-optical equipment with his righthand. The telescope sight will be used to view and aline the object .3.6.3.5 Fine acquisition and tracking periscope viewer mode:

This mode is the same as the telescope sight mode except the periscopeviewer will be used to view and aline the object. Due to the narrowfield-of-view of the Questar lens, an intermediate tracking mode usingthe telescope sight may be necessary when utilizing the Questar lens.3.6.If. Photograph object.- After the object has been acquired andcoarse acquisition of the spacecraft established, the focus of the cameralens system will be adjusted to obtain the clearest image on the ground


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3-8glass as viewed through the periscope viewer. Focusing will be completedprior to fine acquisition and tracking. At the time of closest approach(TOGA - the time the spacecraft or its ground track comes closest to theobject of concern) and after the best tracking possible has been ac-complished, a series of exposures will be made. The pilot will advancethe film, cock the camera shutter, and activate the shutter approximatelyevery 2 seconds until the photographic series has been completed.

The spacecraft Gemini voice recorder will be utilized to recordany astronaut remarks regarding weather over the object, lightingcon-ditions, internal reflections, camera exposure settings, and any devia-tions from the nominal conditions. The spacecraft attitude, rate andthruster-firing information during the exposure series will also be re-quired for postflight analysis. The command pilot will perform thenormal air-to-ground voice communications while the pilot operates thephoto-optical system and records the pertinent remarks. Figure 3-6 isan illustration showing the assembled Questar lens-camera combinationmounted on the right-hand window frame and in use by the pilot. Fig-ure 3-7 identifies the assembled components on the spacecraft window.

3-7 Preflight Considerations3.7-1 Equipment.- The experiment equipment must have resolutionchecks and boresight alinement with the spacecraft prior to flight. Thetype of film to be carried on the mission will be chosen before launchfrom one of the following types: Monochromatic (SO-2C-6, Panatomic-X3 UO O, or Plus-X 3401); color (Aerial Ektachrome 8442); and infrared

(Aerial Ektachrome 8443). The film will require standard refrigerationuntil it is loaded into the film backs immediately prior to placing theexperiment equipment on board the spacecraft. All equipment outer lensesshould be cleaned at this time.3.7.2 Personnel.- The astronauts for the GT-4mission will bethoroughly trained in photographic techniques and use of the experimentequipment. Training equipment will be used during flight simulationsto develop proficiency in performing experiment procedures.

3-8 Inflight ConsiderationsThe astronauts will utilize the detailed flight plan to unstowand mount the experiment equipment, and to acquire, track, and photo-graph the scheduled objects. No special handling requirements are anti-cipated other than normal precision equipment handling. All experimentequipment is designed for "gloved hand" operation and all viewing devicesrequire the astronaut to have his visor open. Representatives for theexperiments will be available throughout the mission at the Mission


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3-9Control Center (MCC), NASA Manned Spacecraft Center, Houston, Texas, toanswer any questions concerning the experiments.

3.8.1 Flight plan.- The detailed flight plan will be released priorto the launch of GT- - and will outline the requirements and photographicobjects for these experiments. The first "coarse" object acquisitionwill be a visual mode with the command pilot maneuvering the spacecraftusing the Gemini optical sight. A second "coarse" (instrument mode) ob-ject acquisition will be used later in the mission for Experiment D-6.In this mode the command pilot will maneuver the spacecraft to a predeter-mined attitude with the spacecraft instruments in order to aline theterrestrial object within the field-of-view of the telescope sight.The "coarse" acquisition mode will be followed by a "fine" acquisi-tion and tracking task. These tasks shall be done in two modes. Thefirst "fine" mode will consist of the command pilot maneuvering thespacecraft using the optical sight while the pilot operates the photo-optical equipment and gives verbal directions to the command pilot. Thesecond "fine" mode will consist of the pilot operating the photo-optical.equipment and maneuvering the spacecraft after the command pilot hasaccomplished "coarse" acquisition of the object 3-8.2 Equipment preparation procedures.- When instructed by thedetailed flight plan, the astronauts will unstow and assemble the equip-ment required for these experiments.3.8.3 Photographic correlation.- The Gemini voice recorder will beutilized to record data necessary for postflight analysis of each photo-graphic series. The following minimum information is required.3.8.3.1 With camera ready for operation:(a) Time of the photographic series(b) Number of photographs exposed in the series and exposurenumber of each(c) Camera shutter speed

(d) Lens aperture (not applicable to the Questar lens)(e) Film type load in the film back (given by the identificationtag on the exterior surface of the film back)(f) Method of object acquisition including comments concerningdifficulty of acquisition and tracking


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3-10(g) Description of object including all possible information con-cerning haze, weather, distinguishable features of the area of concern,and surrounding terrain(h) Any deviations from the nominal conditions3.8.3'2 Every time a film back is changed, the following additionalinformation is required:(a) Time of the film back change(b) Frame count and identification of the film back removed fromthe camera(c) Frame count and identification of the film back installed onthe camera3-8.4 Focus and/or object definition problems Questar lens.- Itwill be desirable to refocus the Questar lens when terrestrial objectsare to be photographed. Since the Questar lens is a long-focal-lengthtelescope, it is desirable for the pilot to examine the objects throughthe lens and record his observations. However, due to variations in thespacecraft tracking rates, it may be difficult to accomplish these twoobjectives.The field-of-view that can be seen on the camera's ground glasswhen terrestrial objects are photographed is approximately l4 500 feetby 23 000 feet. At rate errors of 0.1 degrees-per-second in spacecrafttracking, ground image motion is 1700 feet-per-second. As viewed onthe camera's ground glass, image motion is 2.5 mm-per-second. Thismovement of the object as seen by the pilot may cause difficulties inlens focusing and object definition.3.8.4.1 Object motion problem: If object motion is too great toallow adequate focusing or object viewing, and if spacecraft trackingrate errors cannot be reduced, take the following steps:(a) Focus the Questar lens on celestial bodies only. Do notattempt to focus on terrestrial objects.(b) Use either the optical sight or telescope sight for viewing.Do not attempt to view the camera ground glass image directly throughthe Questar lens.3.8.4.2 Questar lens astigmatism problem: If it is impossible toadequately focus the Questar lens for both horizontal and vertical ob-jects, astigmatism has occurred. This situation would probably occur if


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3-11the photo-optical system or the. spacecraft window has deformed due topressure or temperature variations. If astigmatism occurs, focus thelens for horizontal images (the length of the camera's ground glass) andignore the vertical images.

3.8.5 Focus and/or object definition problems - Nikkor 200-mm lens.-Accurate focus of the Nikkor 200-mm lens is a function of object bright-ness on the camera's ground glass. If necessary for focusing purposes,increase the object brightness by increasing the lens aperture to amaximum of f/4. After adequate focus has been achieved, adjust the lensaperture to the correct exposure setting for the object being photographed.For camera-object distances exceeding 500 feet, a lens aperture settingof "infinity" will provide an adequate focus.

3.9 Postflight Considerations3-9-1 Experiment equipment retrieval.- As soon as possible afterrecovery of the spacecraft, the experiment photo-optical equipment andfilm backs will be removed from the spacecraft. It will be handled asdelicate equipment and carefully packed for shipment on the first air-craft leaving the primary recovery vessel to the NASA Manned SpacecraftCenter, Houston, Texas, for postflight evaluation and film processing.3.9'2 Other required data.- In addition to the original film,other pertinent mission information is required by the Air Force AvionicsLaboratory, Wright-Patterson Air Force Base, Ohio, for evaluation andcorrelation. This includes a listing of the mission intervals when the

photographs were taken, the spacecraft ephemeris, the spacecraft atti-tude, the spacecraft rate, weather conditions over the photographedterrestrial objects at the time of exposure, and any other pertinentdata. A copy of the transcript of the Gemini voice recorder will alsobe required.3.9.3 Postflight debriefing.- Representatives from the U.S. AirForce will attend the mission debriefings. The astronauts will be askedquestions concerning the conduct of these experiments and ways to improvethem on future missions.

3.10 Installation ProceduresThe experiment equipment will be stowed in the GT-^ spacecraft atCape Kennedy, Florida, at some convenient time prior to launch. Table 3-1lists the probable spacecraft cabin stowage areas for this equipment.Other than stowage during launch and reentry, and mounting on the right-"hand window during orbit, this equipment has no other interface with anyspacecraft system other than the operational photo event indicator.


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3-123.11 Equipment Checkout Procedures

3.11.1 Pre installation acceptance. - The experiment flight andspare equipment will receive a pre installation acceptance (PIA.) checkas outlined in MAC SEDR 322. At this time the equipment will be cali-brated on the basis of resolution, transmission, alinement, and mechanical performance.

3-11.2 Alinement. - The experiment flight and backup equipmentwill be alined with the spacecraft as outlined in MAC SEDR3.11.3 Resolution. - A resolution check will be made to determinethe effects of the spacecraft window on the photo-optical system. Thisprocedure is outlined in MAC SEDR 383.

3.12 Flight Qualification RequirementsThe photo-optical equipment listed in .table 3-1 is the only equip-ment required for these experiments. The equipment is designed, built,and tested to operate satisfactorily in accordance with the requirementsof table I of the McDonnell Aircraft Corporation (MAC) Report Number 8 33,"General Environmental Requirements for Model 133P."


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- . 0 EXPERIMENT NUMBER D-8 - RADIATION IN SPACECRAFT

4.1 ObjectiveSuccessful completion of future space missions may depend on ob-taining sufficient advance data concerning the radiation environment,shielding interactions, and dose rate levels that will be encountered.This information is necessary to insure astronaut protection againstambient space radiation. The objective of Experiment D-8 is to obtainaccurate, empirical data that can supplement other space radiation ex-periments and aid in determining the instantaneous and total radiationdose received by astronauts of the Gemini Program. Suitable measuringinstruments will be utilized to fully characterize, qualitatively andquantitatively, the radiation penetrating the cabin of the Gemini space

craft. This data will not only aid in determining the radiation re-ceived by the astronauts, but will yield baseline data to better under-stand the correlation between physical and biological radiation measurements for use in future manned space missions.

4 . 2 Jus tif icat ionThe Gemini spacecraft presents an excellent opportunity to studythe radiation environment and dose levels resulting from passage throughregions of varying radiation intensity. Other scientific experimentswill be performed to measure the radiation levels external to the space-

craft. The internal spacecraft data received from Experiment D-8 willbe correlated with the external measurements to provide a complete pic-ture of the radiation environment encountered. These correlations willbe utilized to confirm or provide empirical corrections to the theore-tical radiation environment predicted. It should be possible to accur-ately extrapolate these data to higher altitudes and other radiationenvironments for use on future manned space missions. In addition,successful operation of the radiation measurements instruments on theGemini missions will prove the feasibility of similar devices for useon future manned space missions.Experiment D-8 is sponsored by the Research and Technology Division,

Air Force Weapons laboratory, Kirtland Air Force Base, New Mexico. Itis funded through the Air Force Systems Command Field Office located atthe NASA Itenned Spacecraft Center, Houston, Texas.

4. 3 ScopeExperiment D-8 will be used to supplement external spacecraft radi-ation measurements by studying the temporal and spatial distribution of


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4-2

dose levels penetrating the spacecraft as a result of passage throughregions of varying high radiation intensity. Under normal conditions,this radiation will consist of energetic electrons and protons in theinner Van Allen radiation belt located over the South Atlantic Ocean.In this region, the radiation "belt dips close to the earth's surfacebecause of the irregular strength of the earth's magnetic field, andis ordinarily referred to as the South Atlantic geomagnetic anomaly.The radiation measurement instruments designed for this experiment areoptimized for response to the radiation level expected in this region.However, to allow for measurement of the low-intensity cosmic ray doserates expected, and for possible high-dose rates of an unusual char-acter, the dynamic range of the instruments has been extended. Twotissue-equivalent, current-mode ionization chamber instruments will beused to measure the variation of absorbed dose-rate inside the cabinas a function of time. Five small packets containing various radiationdetection and measurement devices will be placed at different locationsin the spacecraft cabin to measure the total radiation dose and toascertain their suitability as convenient dosimeters of space radiation.The characterization of the radiation measured will include determina-tions of its ionizing power, penetrating power, contribution to doseaccording to particle type (electron and proton), variation with time,and variation with position inside the spacecraft.

4.4 Experiment Equipment DescriptionThe experiment equipment consists of two active dose rate indi-

cators and five passive type dosimeters. A list of these units withtheir part numbers, weights, and installation locations is given intable 4-1. The are illustrated in figures 4-1, 4-2, and 4-3, and theirspacecraft installation locations are shown in figure 4-4. A detaileddescription of the different type units is given in the followingparagraphs.

4.4.1 Active dose rate indicators.- Two tissue-equivalent, current-mode ionization chamber instruments will be used to measure the variationof absorbed dose-rate inside the spacecraft cabin as a function of time.The Type I unit is permanently mounted on the left hatch and is illus-trated in figure 4-1. The Type V unit is mounted on the right hatch andis constructed so that the radiation-sensitive head can be detached fromthe basic instrument for placement at various locations inside the cabin.This sensor-head is attached to the basic instrument by a 5-foot cablethat has an automatic rewind feature. The Type V unit is illustrated infigure 4-2. Each active dose rate indicator has a Bendix Pygmy electricalconnector that connects the following parameters to the unit.


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4-54.4.1.1 Spacecraft power: Spacecraft regulated electrical powerand telemetry is supplied to each active dose rate indicator by meansof a multi-wire cable running across each hatch. Circuit protectionand isolation is provided to deliver an input regulated voltage of24 0. 4 V dc to the units. The maximum power drain on the spacecraftwill not exceed 0.5 watts continuous for both active units. The elec-trical block diagram is shown in figure 4-5 and the electrical schematicin figure 4-6.4.4.1.2 Telemetry outputs: A total of six electrical output sig-nals from the two active dose rate indicators to the spacecraft pulsecode modulation (PCM) system will provide cabin radiation dose rate andinstrument supplementary data. The output signals will be a varyinganalog voltage ranging from 0.0 to 5-0 V dc into an impedance of 100 Kor greater. These signals will be recorded and/or transmitted by the

spacecraft PCM system. The PCM system will sample the instrument out-put signals at a frequency of 1.25 times per second. The Type I unitwill have four telemetry (TM) outputs and the Type V unit will havetwo TM outputs,4.4.2 Passive dosimeters.- Five passive dosimeters will be used tomeasure the total radiation dose received at various locations insidethe spacecraft cabin. These units are all alike with each onecon-taining a 0 to 200 milliradian pocket ionization chamber, 0.10 to10 000 radian silver activated phosphate needles, a 0.01 to 10 000 radianthermoluminescent dosimeter, a 0.005 to 10 000 radian thermoluminescentdosimeter, and 0.005 to 10 000 radian gamma-electron sensitive films.

These elements are hermetically sealed in the dosimeter container. Atypical passive dosimeter is illustrated in figure 4-3. The five unitsare installed in the spacecraft in the approximate locations shown infigure 4-4 and require no spacecraft power or telemetry.

4.5 Operational DescriptionThe astronauts will have a detailed flight plan that will list theoperations with the Type V dose rate indicator. These exercises willbe performed while the spacecraft is passing through the South Atlanticanomaly. The active dose rate indicators receive spacecraft electrical

power and start to operate as soon as the spacecraft power is turnedon prior to launch. Operational functions of each type of radiationmeasuring instrument are given in the following paragraphs.4.5-1 Active dose rate indicator - Type I.- The Type I activeunit is fully automatic in operation and does not require astronautparticipation. It will measure the instantaneous radiation dosage re-ceived at the spacecraft left hatch. The data obtained will be telem-etered to appropriate ground receiving stations for relay to the MissionControl Center (MCC), Houston, Texas.


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4.5.2 Active dose rate Indicator - Type V. - The Type V activeunit is fully automatic in operation and vill measure the instantaneousradiation dosage received at the spacecraft right hatch and accordingto astronaut placement in the spacecraft cabin. As instructed by themission flight plan, the pilot will remove the radiation-sensitive headfrom its secured location on the right hatch and place it for a periodof 1 minute at each of several pre-planned positions. These positionsare: against his chest covering the sensor with his glove, between hislegs in the groin area, under his left arm-pit, in front of the right-hand cabin window, in front of the spacecraft instrument panel midwayfrom the floor to the top of the cabin, and on the cabin floor near hisfeet. The data obtained will be telemetered to appropriate ground sta-tions for relay to the MCC-Houston. In addition, the pilot must recordthe time and sensor-head location at the beginning of each position, andthe time at the start and completion of each series of six measurements.Figure 4-7 is an illustration showing the radiation-sensitive head inuse by the pilot.

4.5.3 Passive dosimeters.- The five passive dosimeters do not re-quire astronaut participation, spacecraft power, or spacecraft telemetry.They will measure the total radiation dose received at various locationsinside the spacecraft.

4.6 Preflight Considerations4.6.1 Equipment calibration.- The two active dose rate indicators

will require calibration checks during Spacecraft Systems Test (SST) atthe McDonnell Aircraft Corporation plant at St. Louis, Missouri; andduring prelaunch preparations at Cape Kennedy, Florida. The final cali-bration check at Cape Kennedy should be made not more than 3 weeks priorto launch and before spacecraft installation of the five passive dosi-meters. Each calibration check will require a 2-hour period of accessto the hatch-mounted active units. During this time, there will bethree 10-minute periods in which the spacecraft work area will have tobe cleared of personnel due to the radiation calibration source. The90radiation source to be utilized is 0.1 millicurie of Sr - Y beta rays.The maximum range of these beta rays in air is less than 10 yards.Spacecraft telemetry should be on and TM records are desired duringthese calibrations. There are no calibration checks or tests requiredfor the passive dosimeters.

4.6.2 Equipment preflight servicing.- The five passive dosimeterflight units must be installed in their respective spacecraft locationsas close as possible to launch. The flight units will be furnished toCape Kennedy, Florida by an Air Force Weapons laboratory representativeshortly before scheduled installation. There will be no tests run on


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4-5the units before or after installation, except for physical dimensionchecks. Each passive unit has its specific mounting orientation on thespacecraft, and it is important that the proper unit be installed inthe designated location. At no time after installation should any ra-diation source be placed near the spacecraft or within the spacecraftcabin. The passive units are hermetically sealed and have no specialhandling requirements. However, they are very sensitive to temperatureand must never be allowed to exceed 120 F prior to launch. There areno preflight servicing requirements for the active units except for thefinal prelaunch calibration check. This check must be completed priorto spacecraft installation of the passive units.

4.6.3 Personnel.- The astronauts for the GT-4 mission will bethoroughly trained in the use of the Type V active dose rate indicator.They must be familiar with the portable radiation-sensitive head, themethod of release from its secured position on the right hatch, therequired inflight movements and locations of the sensor head, and themethod of restowing the head on the hatch. Training equipment will beused during flight simulations to develop proficiency in performingthe experimental procedures. A preflight briefing will give the astro-nauts final details concerning this experiment.

4.7 Inflight ConsiderationsThe astronauts will utilize the detailed flight plan for astronaut

participation in this experiment. No special handling requirements areanticipated other than normal precision equipment handling. Theradiation-sensitive head is designed for "gloved hand" operation.Representatives for the experiment will be available throughout themission at the MCC-Houston to answer any questions concerning theexperiment.4.7.1 Flight plan.- The detailed flight plan will be releasedprior to the launch of GT-4. It will outline astronaut participationfor the experiment during a minimum of three orbital passes through theSouth Atlantic geomagnetic anomaly. At the completion of each passagethrough the anomaly, the sensor head will be returned to the stowed

position on the right hatch.4.7.2 Reporting requirements.- During astronaut participation inthis experiment, the pilot will record the time at the beginning andend of each of the three 6-minute exercises. This record will be cor-related later with the spacecraft ephemeris containing longitude,latitude, and altitude as a function of time. The pilot will also


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4-6record the time and sensor-head position as he places it at the variouslocations in the cabin.

4.8 Postflight Considerations4.8.1 Experiment equipment retrieval.- At a convenient time imme-diately after recovery of the spacecraft, the five passive dosimeterswill be removed from the spacecraft and shipped on the first aircraftleaving the primary recovery vessel so as to arrive at the NASA MannedSpacecraft Center, Houston, Texas, within 24 hours. They will then betransferred to the Biophysics Branch, Air Force Weapons Laboratory,Kirtland Air Force Base, New Mexico. The flight units are required atthe Laboratory within 2 days of recovery to permit analysis of the totalradiation dose measured. At no time should the units be allowed inproximity with any radiation source. Also, the units must never beallowed to exceed a temperature of 120 F.With NASA concurrence, the active units mounted on the spacecrafthatches will be returned to the Air Force Weapons Laboratory. Thereare no postflight calibration requirements for these active units.4.8.2 Data requirements.- In addition to the retrieval of thepassive dosimeters, certain other mission information is necessary to

analyze the data obtained from this experiment. A transcript of therecord made during astronaut participation with the Type V active unitis needed. Also, certain telemetry and spacecraft orbital data isrequired as follows.4.8.2.1 Raw data strip charts: The course and fine radiation rateoutputs from both active type units, the calibrate monitor, and the tem-perature monitor telemetry signals for the entire period of the missionare needed in strip chart form. Recorder speed desired is 1-inch ofoutput per minute of data. The 0-5 volt signal output must be repre-sented by no less than a 2-inch total deflection. All six signal out-puts on a single strip of 12-inch wide paper with a common time ref-erence would be adequate for these data reduction purposes.4.8.2.2 Computer analysis; The telemetry data obtained from theactive units must be correlated with location in a magnetic coordinatesystem calculated from the spacecraft geographic coordinate of altitude,latitude, and longitude. Therefore, it is necessary that the space-craft ephemeris be merged with the experiment telemetry data, preferablyas a function of Greenwich mean time. It is expected that only duringthe time the spacecraft spent in the region of the South Atlantic anomalywill there be enough radiation present to produce a reading with theactive dose rate indicators. It is desired that the NASA Manned Space-craft Center provide data analysis and reduction as required and


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requested by the Air Force Weapons laboratory. Machine plots of theadjusted dose rate versus time for both the Type I and Type V units ispart of the reduction required.

.8. 2. 3 Additional required data: In order that a more thoroughanalysis of the experiment data obtained can be performed at AFWL at alater date, a low-density (200 bpi)tape in floating binary format con-taining the spacecraft ephemeris merged with the experiment data isneeded. For the tape to be compatible with the AFWL CDC l60 computer,the tape must be generated on the NASA-MSC CDC 3600 computer. The fol-lowing data should be contained on the tape:(a) Time in seconds(b) Altitude in km(c) North latitude(d) East longitude(e) The six experiment data pins in this order: XB01, XB02, XB17,XB06, XB03, and XBl8.The data may be either in voltage (0-5 volts correct to two digits )or in the digital equivalent value of PCM bits.^.8.3 Fostf light debriefing.- This experiment does not require anypostflight astronaut debriefing.

k.9 Installation Procedures^ 4 - . 9- 1 Active dose rate indicators. - The Type I and Type V activedose rate indicators will be installed on the spacecraft left and righthatches respectively at the MAC-St. Louis, Missouri, plant. These units

will receive periodic calibration checks while at MAC-St. Louis, andafter spacecraft delivery to Cape Kennedy, Florida. Physical installa-tion consists of bolting the active units to the hatch structure andconnecting the electrical power -telemetry signal cable.

k. 9. 2 Passive dosimeters. - The five passive dosimeters will beinstalled in the spacecraft in their assigned positions as close aspossible to launch of the GT-4 spacecraft from Cape Kennedy, Florida.Physical installation consists of bolting the units to the areas pre-viously prepared to receive them. They have no other interface withthe spacecraft or its systems. In the event of a delay of 7 days ormore in the GT- launch after the passive units have been installed,the passive dosimeters must be replaced with fresh units. The passive


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units vill be hand-carried to Cape Kennedy, Florida, by AFWL repre-sentatives and delivered to appropriate MAC or NASA personnel forinstallation into the spacecraft.

4.10 Equipment Calibration Procedures^. 10.1 Active dose rate indicators.- The active dose rate indicatorflight units will be installed in the GT-4 spacecraft at the MAC plantin St. Louis, Missouri. During SST testing and every 90 days thereafteruntil launch from Cape Kennedy, Florida, the units will have a calibra-tion check. A final calibration check on these units will be made atCape Kennedy, Florida, within 2 weeks of launch.4.10.2 Passive dosimeters.- The five passive dosimeters do not re-quire calibration before flight. The flight units will be installedshortly before launch of the GT-4 spacecraft from Cape Kennedy, Florida.

4.11 Flight Qualification RequirementsThe radiation measuring instruments listed in table 4-1 are theonly equipment required for this experiment. The equipment is designed,built, and tested to operate satisfactorily in accordance with therequirements of table I of the McDonnell Aircraft Corporation (MAC)Report Number 8433, "General Environmental Requirements for Model 133P."


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5-15.0 EXPERIMENT NUMBER D-9 - SIMPLE NAVIGATION

5.1 ObjectiveManned space flight, both in and out of earth orbit, dictates thatman have the capability for space navigation. Ideally, this capabilitywould be independent of ground support and provide a reliable navigationsystem in the event of failure of all earth-ground communications andguidance facilities. If possible, it should be a manual system and in-volve only the simplest of onboard spacecraft equipment. In support ofthese goals, Experiment D-9 has three basic objectives: to test andevaluate the theoretical concept of a manual space navigation system;to test and improve on the design of manual space navigation equipment;

and to provide basic data on the observable phenomena of space that maybe used for navigational purposes. The experiment will utilize theGemini astronauts to gather celestial data and test two manual naviga-tion system concepts. Two special navigation instruments will be usedin these concepts, a space stadimeter and a space sextant. The informa-tion and data obtained from these instruments will be used to develop asimple, lightweight, manual space navigation system that makes maximumuse of man's capabilities.

5.2 JustificationMany theories exist regarding the usefulness of certain observablephenomena for space navigation, but little actual data is available.Analytical studies and atmospheric flight tests conducted by the UnitedStates Air Force Avionics Laboratory indicate that man has the capabi-lity to determine all necessary spacecraft orbital parameters if he hasthe proper on-board sighting instruments and manual computational aids.This capability is desired as a backup emergency procedure for earth-orbital flights and for development of the Apollo space navigation sys-tem. Two special instruments have been developed for use on Geminispacecraft to allow detailed manual-visual examination of the spacephenomena thought to be best for space navigation purposes. These twoinstruments will make maximum use of the observable phenomena necessary

for solution of the space navigation problem. The Gemini astronauts willprovide the necessary instrument alinement and object-sighting. The dataobtained from Experiment D-9 will permit completion of the design of amanual space navigation system and related equipment that can be used onfuture manned space missions.Experiment D-9 is sponsored by the Research and Technology Division,Air Force Avionics laboratory, Wright-Patterson Air Force Base, Ohio. Itis funded through the Air Force Systems Command Field Office located atthe NASA Manned Spacecraft Center, Houston, Texas.


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5-2

5-3 Scope

There are two basic space phenomena which appear to be the moststable and useful for space navigation purposes. These are the bluehaze and green line horizons. An unknown phenomenon which may be usefulis the existence of the green emission line of the day side. A secondis the usefulness of the shade differentiation between the black ofthe dark earth and the black of space behind it. In addition, theremay be other horizons which have been overlooked due to the lack ofphenemona examination in this area.Experiment D-9 will utilize the Gemini astronauts to test simple

stadimetric and sextant measuring devices to make visual sightings andmeasurements on the stars and earth horizons. Data from these sightingswill be used for postflight computations with manual type computers todetermine the spacecraft orbital parameters. Comparison of these com-putations with actual orbital parameters will be made to determine theaccuracies of the sighting procedures.Only the space sextant will be carried on the GT-4 mission. Themission flight plan will list the detailed sightings to be made of theblue haze and green line horizons. No attempt will be made to providedefinitive data on the unknown horizons. Only general information onthese phenomena will be studied, with the judgment and comments of the

astronauts being of prime importance. Experiment D-9 will help toprovide answers to the following questions by comparison of astronaut-measured and observed information with the ground stations-obtaineddata:(a) What horizon is most useful for star-horizon angularmeasurements?(b) What part of that horizon should be used: top, middle, orbottom?(c) Can any or all visual horizons be made sharper with filters?(d) Are any horizons discontinuous?(e) What are the mean heights of the visible horizons?(f) What kind of accuracies are possible in visual-optical stadi-metry and star-horizon measurements from an orbiting spacecraft?(g) What are the sources of measurement error; what are theirmagnitudes; and what can be done to achieve greater accuracy?


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5-3Experiment Equipment Description

The experiment equipment consists of a stadimetric altitude-measuring device (space stadimeter) and a star-horizon angle-measuringdevice (space sextant). These instruments vill be stowed inside theGemini spacecraft cabin and be easily available to the astronauts foruse during the mission. They will be hand-held for observations throughthe spacecraft windows. All sightings, alinements, and data readoutswill be accomplished by the astronauts. The instruments are self-contained and require no spacecraft power or telemetry. Although onlythe sextant will be carried on the GT- mission, a detailed descrip-tion of each instrument is given in the following paragraphs.5. .1 Space stadimeter.- The space stadimeter will be used to makeblue haze and green line horizon curvature measurements for altitude de-terminations. It is stowed in a shock-insulated container in the center-

line stowage box of the spacecraft cabin. It is approximately 5^ inches- ] < high by 6^ inches wide by 7 inches long and weighs 8.26 pounds. It hasGFAE part number AF69998 and is illustrated in figure 5-1. The stadi-meter contains four 1-5 V U50 mA dry cell batteries to provide reticleillumination.

5. .2 Space sextant.- The space sextant will be used to make star-horizon angular measurements for orbit orientation determinations. Itis stowed in a shock-insulated container in the center-line stowage boxof the spacecraft cabin. It is approximately 5p inches high by 6^ incheswide by 7 inches long and weighs 8.26 pounds. It has GFAE part numberAF69999 and is illustrated in figure 5-2. The sextant contains four1 V ^50 mA dry cell batteries to provide reticle illumination.

5.5 Principals of OperationThe equations necessary for determination of spacecraft orbitalparameters generally amount to a set of six simultaneous equations.The complete description of an orbit, with respect to size, shape,and orientation in three-dimensional space, requires the determi-nation of six independent parameters from these equations. Theseparameters could be: the period of the orbit; the eccentricity of theorbit; time from perigee to first measurement point; orbital inclinationto the equatorial reference plane; sidereal hour angle of the line ofnodes (the line which is the intersection of the orbital and equatorialplanes); and the true anomaly of the line of nodes (measured in the


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orbital plane). The first three parameters (period, eccentricity, andtime) can be used to determine the size and shape of the orbit and areobtained by use of the space stadimeter. The remaining three parameters(orbital inclination, sidereal hour angle, and true anomaly) can be usedto describe the orbit orientation and are obtained by use of the spacesextant. The principals of operation for both instruments are given inthe following paragraphs.

5.5.1 Space stadimeter.- The space stadimeter is used for space-craft altitude and time determinations, which, with the proper computa-tions, will yield the orbital size and shape. The operational charac-teristics are as follows:5.5.1.1 Theory: Spacecraft range (or altitude) from a sphericalearth's surface, and its distance from the center of the sphere, arefunctions of the angle subtended by lines from the spacecraft tangent tothe surface of the sphere. Measuring this angle (or half-angle) willgive the distance from the surface, assuming a known radius of the earth,and performing the proper calculations (see A, figure 5-3).However, for near earth orbits of the type planned for the Geminispacecraft, the total angle subtended by the lines tangent to the earth'ssurface approaches 180. Observation of both limbs of the earth througha spacecraft window to accurately measure this wide angle becomes im-practical. Therefore, a method for obtaining the necessary informationusing only a portion of the horizon has been developed. In this method,the center of a low power telescope is pointed at some reference earthhorizon. The telescope is then positioned so that a single, center crosshair cuts a chord across the horizon curvature, intersecting the curva-ture at the center and near the outer edge of the telescope field-of-view (see B, figure 5-3). A second movable cross hair, originally coin-cident with the first, is then rotated about the center point to intersectthe horizon curvature at the center and the opposite edge of the telescopefield-of-view (see C, figure -3).The subtended half-angle, and thus the altitude of the spacecraft(see A, figure 5-3)>are functions of the angle between the two crosshairs (see C, figure 5-3), the known radius of the earth plus the alti-tude of the reference horizon, and the angular field-of-view of the tele-scope corrected for the non-sphericity of the earth. If these parametersare used in conjunction with an appropriate graph or table, the spacecraftaltitude can be determined for this position without extensive computation.5.5.1.2 Operation: The space stadimeter contains the necessaryoptics and equipment to measure the subtended half-angle. However, simul-taneous alinement in the field-of-view of the two edge points and thecenter point, with the chord lines yielded by intersecting the earth


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5-5

horizon, is very difficult for a large field-of-view (see D, fig. 5-3).In the space stadimeter, the movement of the cross hairs is simulatedby the movement of a prism, and the three points of interest are opti-cally brought to the center of the field-of-view for proper alinement(see E, fig. 5-3). The angle subtended by the chords is read out indegrees and minutes directly on the instrument. This method enablesfull use to be made of the large field-of-view through the Gemini space-craft window to yield orbital size and shape without scrificing resolu-tion and ease of visual alinement.

5.5.2 Space sextant.- The space sextant is used to determine theorientation of the spacecraft orbit in time and space. The operationalcharacteristics are as follows.5.5.2.1 Theory: Determination of the orientation of a spacecraftorbit in time and space can be made using angular measurements betweenthe earth horizon and selected stars. If knowledge of the spacecraftaltitude and orbital size and shape has been previously determined, thehalf-angle subtended is known (see A, fig. 5-3). From these data and

t i i e measured angle between the earth horizon and the star, the angle be-tween the spacecraft zenith and the star, called the co-altitude, can bedetermined. Through the use of appropriate tables, two such co-altitudedeterminations on each of three selected stars uniquely determines theplane of the orbit.5.5.2.2 Operation: The space sextant is a star-horizon angle

measurement device that operates very similar to a normal sextant, buthas an optical system specifically designed for optimum performance inthe space environment. The selected star will be identified throughthe spacecraft window and the instrument sighted on it. The instrumentoptics will then be rotated until the horizon and star are superimposed.This measures the angle between the depressed horizon and the star. Withthis data and the other orbital parameters, the angle between the space-craft zenith and the star (co-altitude) can be computed. From this co-altitude, the orbit orientation parameters can be computed.

5.6 Operational DescriptionThe astronauts will have a detailed flight plan that will list theobservations and measurements to be made with the space sextant.These measurements will be made during both the day-side and night-sideportions of the orbits. The observations are time phased and affectedby orbit variations. In order that these variations detract from thebasic experiment objectives in the least possible manner, it is neces-sary that the following criteria be used in making the observations:


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5-6(a) Measurements are needed over the entire range of earth lighting

from direct to completely slant rays of the sun.(b) It is assumed that the direction of travel of the spacecraft(whether the horizon is moving away or approaching, or whether the lightis diminishing or increasing) will have an effect on the measurements.(c) It is necessary when making an observation that the sun notstrike the spacecraft window. Orientation of the vehicle must be in sucha manner as to place a shadow over the window. In the Gemini spacecraft,this would be with the heat shield toward the sun. For this reason, thespacecraft must be turned 180 in yaw in the middle of both the daylightand night sides.(d) Work periods in which an astronaut is actively making observa-tions and recording measurements should not exceed fatigue limits, esti-mated to be approximately ^5 minutes for this type of measurement. Theexperiment observation sequences will be programed in -minute incre-ments. Division of these increments in other ways is generally not det-rimental. However, in order to take advantage of the effects of theshort-term learning curve, it is desirable that observations be made ingroups of three in sequence.(e) Control measurements are necessary to check repeatability be-tween measurements and between individuals. Therefore, both astronauts

will made observations and portions of the measurements are repeated.Even though the space sextant is the only instrument to be carried onthe GT-1* - mission, operational descriptions for both instruments are givenin the following paragraphs.5.6.1 Space stadimeter.- The space stadimeter will be used to makespacecraft altitude measurements. It will be hand-held by the astronautsand does not require spacecraft power or telemetry. The spacecraft willbe maneuvered to obtain the proper view of the earth horizon as detailedby the mission flight plan. After the instrument cross hairs have beenalined properly with the horizon, the readout angle and time will be re-corded. These measurements will be repeated at approximate 5-minute in-

tervals around the orbit. Only three measurements would be necessary topermit the astronaut to determine his altitude and orbit size and shapewithout assistance from ground facilities. However, for experimentalpurposes, several series of observations will be made at different por-tions of the spacecraft orbit. Figure 5-^ is an illustration showingthe stadimeter being operated by an astronaut. Reference figure 5-5 for


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5-7the spacecraft orbital sequence during the following observations andmeasurements.

5.6.1.1 Primary measurements of the daylight blue haze horizon:These measurements will be taken while the spacecraft is on the daylightside of the earth-orbit, using a blue filter to accentuate the blue hazehorizon. Starting with the twilight of the orbital morning, the space-craft will be alined at a relative heading of l80 to the orbital trackto look away from the sun. The first stadimetric measurement will betaken as the sun illuminates the horizon behind the spacecraft. Thestadiraeter will be alined with the blue haze horizon and the time andinstrument readings recorded. Near the middle of the daylight side thespacecraft will be turned to either 90 or 270 so as not to look intothe sun. Additional measurements will be taken from this position. Thespacecraft will then be turned to a relative heading of 0. Measurementswill continue to be taken as the spacecraft approaches the night twilightregion.

5.6.1.2 Primary measurements of the 5577A* green emission line:These measurements will be taken while the spacecraft is on the nightside of the earth-orbit, using a green band-pass filter. The spacecraftwill be alined to a relative heading of 0 to the orbital track andmeasurements taken. At the half-way point on the night side, it will beturned to either 9(f or 2?0 and additional measurements taken as itcontinues into the morning twilight region.5.6.1.3 Correlation check of the night side 5577A green emissionline and investigation of its visibility on the day side: Using thegreen band-pass filter, measurements will start approximately two-thirdsof the way around the night side of the earth-orbit, and continue intothe daylight side. Special care should be used by the astronauts to re-tain dark adaptation. If the green line is not visible on the daylightside, measurements will continue as programed but using the blue filter.5.6.1. Correlation check of the daylight blue haze horizon: Thesemeasurements will start at the midpoint of the daylight side and continueinto the night twilight region.5.6.1.5 Measurement of individual bias using the other astronaut:Data obtained by one astronaut operating the stadimeter will be corre-lated with the data obtained from the other astronaut's measurements.This should establish the personal bias which might be expected in meas-urements of this type. Correlation measurements will be taken duringthe last half of a night side orbit using the green band-pass filter,and during the last half of a day side orbit using the blue filter.


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5-8

5-6.1.6 Horizons of opportunity: Using the neutral density filter,the astronaut will select a portion of the day side horizon which appearsto be the most consistent and well defined. He will use the same sche-dule outlined in paragraph 5.6.1.1, starting at sunrise and taking meas-urements into the night twilight region.

5.6.1.7 Definition of the dark-shades horizon: Using the zerofilter, the astronaut will make stadimetric measurements using the shadedifference between the earth and space. Measurements will begin halfwayinto the night side and continue into the morning twilight.5.6.1.8 Additional correlation check of the night side 557?Agreen emission line: This correlation check will be the same as para-

graph 5.6.1.3* but will measure the first portion of the night sideorbit not previously covered.5.6.1.9 Additional correlation check of the daylight blue horizon:This correlation check will be the same as paragraph 5.6.1. , but willmeasure the first portion of the day side orbit not previously covered.5.6.1.10 Additional data: During any unforeseen or previously non-appropriated time during the mission, the astronauts are requested toure any horizon of opportunity using their discretion for filters anddirection. A record of all pertinent data concerning the observationsmust be kept.5.6.2 Space sextant.- The space sextant will be hand-held by theastronauts to make star-horizon observations using the same approximatesequence and reference horizons as for the stadimetric measurements. Ineach observation, the selected star will be optically moved to. aline orbe superimposed on the horizon. The astronaut will look through thewindow and identify thet selected star, sight the sextant, and opticallymove the star to the horizon. For observations away from the directionof flight, the horizon will be placed slightly below the star and thetime of star-passage through the horizon will be recorded. When the ob-servations are along the direction of flight, the horizon will be ini-tially placed above the star, the observation being perpendicular to the

plane of the orbit. In this type of, measurement, time is less criticaland the two images can be directly alined.


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5-95-7 Preflight Considerations

5-7-1 Equipment.- The space sextant flight unit will be deliveredto Cape Kennedy, Florida, approximately 2 weeks before scheduled launchof the G-T-4 spacecraft. Only the prescribed preinstallation acceptanceprocedures will be conducted on the instrument. The sextant prisms andlens should be checked to insure that they are clean. The instrumentwill be placed in its spacecraft stowage container and stowed in theassigned position in the centerline stowage box.5-7-2 Personnel.-

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Experiments for GT-4 Mission

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