Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident

 

Volume 3: Appendix O - NASA Search, Recovery and Reconstruction Task Force Team Report

Volume 3: Enclosure 5: SRB INCREMENTAL RECOVERY PLANNING.

 

 

[O230] REPORT CHANGE LOG

as of May 12, 1986.

STS-51L DATA AND DESIGN

ANALYSIS TASK FORCE

SEARCH, RECOVERY AND RECONSTRUCTION

TEAM REPORT

 

Volume 3

 

CHANGE NOTICE NO.

CHANGE NOTICE DATE

PAGES AFFECTED

ITEMS AFFECTED

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1

5/12/86

Create Volume 3

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Enclosure 5

(From Volume 2)

Complete Update

.

Colonel Edward A. O'Connor, Jr.

Date

 

[O231] LIST OF VOLUMES (separately bound)
 

VOLUME 1

REPORT SUMMARIES

 

VOLUME 2

Enclosure 1. MISSION 51-L SHUTTLE MISHAP-SURFACE SEARCH
Enclosure 2. RADAR DATA ANALYSIS AND IMPACT ESTIMATION FOR STS 51-L DEBRIS .
Enclosure 3. STS 51-L RIGHT SRB REPORT NO. 82-SR-86-07,
Enclosure 4. SEARCH, CLASSIFICATION AND RECOVERY
 
VOLUME 3
THIS VOLUME
Enclosure 5. SRB INCREMENTAL RECOVERY PLANNING
 
VOLUME 4

 

Enclosure 6. RECOVERED ET DEBRIS HARDWARE ASSESSMENT,
Enclosure 7. OCEANOGRAPHY
Enclosure 8. SPACE TRANSPORTATION SYSTEM, MISSION 51-L STRUCTURAL RECONSTRUCTION AND EVALUATION REPORT (Standard Accident Report)
Enclosure 9. CONTACT #131 AND #712 RECOVERED RH SRB AFT FIELD JOINT EVALUATION
 

[O232SOLID ROCKET BOOSTER INCREMENTAL RECOVERY PLANNING (May 1, 1986)

Approved:

Alexander A. McCool

Director, Structures and Propulsion Laboratory

NASA Marshall Space Flight Center

SOLID ROCKET BOOSTER INCREMENTAL RECOVERY PLANNING

PREPARED BY:

NASA, Marshall Space Flight Center
Alexander A. McCool, Director, Structures and Propulsion Laboratory
Keith D. Coates
W. Leon Ray
Fred Jankowski
 
Morton Thiokol, Inc.
Lamoine R. Jensen
Gregory G. Gorman
Dennis R. Crawford
Mack H. Phillips
Jerry Burn
Chuck D. Nighswonger
Robert C. Hillard
 
USBI Booster Production Co., Inc.
Hugh E. Fursdon
William F. Imre
 
PRC Illustrations
Lewis J. Wallace, Jr.
Caroline B. Zaffery
George H. Sauro, Jr.

 

[O233] TABLE OF CONTENTS

I. SCOPE AND INTRODUCTION.
A. SCOPE.
B. INTRODUCTION.
II. DESCRIPTION OF SRB.
A. GENERAL.
B. SRB SYSTEMS.
1. Forward Assembly.
a. Nose Assembly.
b. Forward Ordnance Ring.
c. Forward Skirt.
2. Solid Rocket Motor (SRM).
a. Solid Rocket Motor.
b. Structural.
C. SRB SUBSYSTEM.
1. Systems Tunnel.
2. SRB/ET Aft Ring.
3. TVC Subsystem.
4. Separation Subsystem.
5. Recovery Subsystem.
6. E&I Subsystem.
a. Operational System.
b. RSS.
III. IDENTIFICATION OF HARDWARE.
A. METHOD OF IDENTIFICATION.
1. Assets.
2. Identifying Characteristics.
B. ANALYSIS OF VIDEO, AUDIO, AND PHOTOGRAPHS.
C. IDENTIFIED HARDWARE NOT RECOVERED.
IV. RECOVERY PLAN.
A. RECOVERY ASSETS.
B. DEVELOPMENT OF PLAN.
C. SAFETY AND HAZARD CONSIDERATIONS.
V. DESCRIPTION OF RECOVERED HARDWARE.
VI. DISPOSITION OF RECOVERED HARDWARE.
A. IDENTIFICATION AND RECONSTRUCTION OF RECOVERED HARDWARE.
B. PERCENTAGE OF RECOVERED SRM HARDWARE.
C. PROPELLANT DISPOSAL OPERATIONS.
VII. SUMMARY AND FINDINGS.
 
 
 
LIST OF FIGURES.
 
1. 51-L Coordinate System.
2. Solid Rocket Booster Structure.
3. SRM Factory/Plant Joints.
4. SRM Field Joints.
5. SRB/ET Aft Attach Strut.
6. SRB/ET Upper Strut Assembly (RH).
7. SRB/ET Aft Attach Strut.
8. Radar Trajectory Plot.
9. Forward Segment Burn Back Pattern.
10. Forward Center Segment Burn Back Pattern.
11. Aft Center Segment Burn Back Pattern.
12. Aft Segment Burn Back Pattern.
13. Contact 11. Left- Hand (LH) Attach Segment.
14. Contact 21-1. RH Aft Segment/Dome/Stiffener.
15. Contact 21-2. Case Tang Segment.
16. Contact 21-3. RH Aft Segment Fragment.
17. Contact 21-4. Aft Segment- Stiffener.
18. Contact 21-5. Aft Segment- Stiffener Ring Segment.
19. Contact 21-6. Aft Segment-Stiffener Segment.
20. Contact 21-7. SRB Aft Segment Stiffener Ring Section.
21. Contact 21-8. SRB Fragment.
22. Contact 21-9. Aft Segment-Stiffener.
23. Contact 24. Left Hand Aft Segment.
24. Contact 26-1. LH Aft Center Segment, Forward Cylinder.
25. Contact 26-2. LH Aft Center Segment, Forward Cylinder.
26. Contact 41. Forward Dome with Igniter.
27. Contact 195. Section of Factory Joint Tang.
28. Contact 214. Section of Forward Center Segment.
29. Contact 292. Section of Field Joint Clevis.
30. Contact 301. Section of Factory Joint Clevis.
31. Contact 325. SRB Case Cylinder-Clevis Joint.
32. Contact 502. RH SRB Cylinder Segment, Field Joint Tang.
33. Contact 579. Section of Field Joint Clevis.
34. Contact 11, LH ET Attach Segment.
35. Contact 11, LH ET Attach Segment.
36. Contact 21-1, RH Aft Case Segment, Aft Stiff/Aft Dome Joint.
37. Contact 21-2, RH Aft Segment, Forward Stiffener.
38. Contact 21-3, RH Aft Segment, Stiff/Stiff Joint.
39. Contact 21-4, RH Aft Segment, Aft Stiffener.
40. Contact 21-5, RH Aft Segment, Forward Stiffener.
41. Contact 21-9, RH Aft Segment, Aft Stiffener.
42. Contact 26-1, LH Aft Center Segment, Forward Cylinder.
43. Contact 26-2, LH Aft Center Segment, Forward Cylinder.
44. Contact 131, RH Aft Center Segment, Aft Cylinder Dimensional Outside View.
45. Contact 131, Outside Surface.
46. Contact 131, Inside Surface View of Burned Area.
47. Contact 131, Aft Center Segment, Aft Inside Dimensional View.
48. Contact 131, Insulation Profile.
49. Contact 131, Insulation Profile .
50. Contact 131, Segment Wall Profile.
51. Contact 131, Segment Wall Profile.
52. Contact 131, Propellant Profile.
53. Contact 195, Forward Center Segment, Forward Cylinder.
54. Contact 196, LH Forward Dom.
55. Contact 214, Case Cylinder Fragment.
56. Contact 292, LH Aft Segment, Aft ET Attach, Outside View.
57. Contact 292, LH Aft Segment, Aft ET Attach, Outside View.
58. Contact 301, RH Forward Segment, Aft Cylinder.
59. Contact 325, RH Forward Segment, Aft Cylinder.
60. Contact 433, Aft Center Segment, Forward Cylinder .
61. Contact 433-1, RH Aft Center Segment, Aft Cylinder.
62. Contact 433-2, RH Aft Center Segment, Aft Cylinder.
63. Contact 468, Forward Segment, Aft Cylinder.

[O234]

64. Contact 487, Forward Skirt Clevis Joint.
65. Contact 502, Forward Center Segment, Aft Cylinder.
66. Contact 524, Case Cylinder Segment Fragment.
67. Contact 579, RH Aft Segment, Attach Segment.
68. Contact 605, Forward Segment, Forward Cylinder.
69. Contact 615-1A, RH Forward Center Segment, Forward Cylinder.
70. Contact 615-18, RH Forward Center Segment, Forward Cylinder.
71. Contact 615-2, RH Forward Center Segment, Forward Cylinder.
72. Contact 615-3, RH Aft Segment, Aft Stiffener.
73. Contact 615-4, Case Cylinder Fragment.
74. Contact 631, Forward Center or Aft Center Segment Forward Cylinder.
75. Contact 635, LH Forward Segment, Forward Cylinder.
76. Contact 699, RH Forward Center Segment, Aft Cylinder.
77. Contact 711, Forward Dome Fragment.
78. Contact 712, RH Aft Segment, Attach Segment, Interior Surface.
79. Contact 712, RH Aft Segment, Attach Segment, Exterior Surface.
80. Contact 712, RH Aft Segment, Attach Segment, Propellant Profile.
81. Contact 5038, Forward Segment, Aft Cylinder.
82. Contact 5039, Case Cylinder Fragment.
83. Contact 5124, LH Diagonal Strut.
84. Contact 5126-1, Forward Segment, Aft Cylinder.
85. Contact 5126-2, Forward Segment, Aft Cylinder.
86. Contact 5128, Forward Segment, Case Cylinder.
87. RH SRB Recovered Debris.
88. LH SRB Recovered Debris.

 

LIST OF PHOTOGRAPHS

1. Upper and Diagonal Struts.
2. Lower Strut (Installed).
3. TVC System.
4. SRM Segment Nameplate.
5. Contact 26-1, SRM LH Aft Segment, Pressure Port, Tang End.
6. Contact 195, SRB RH Segment, Propellant Profile.
7. Contact 195, SRB LH Segment, System Tunnel.
8. Contact 11, SRB LH Segment, Component Serial/Part Number.
9. Contact 11, SRB LH Segment, Propellant Burn Back Pattern.
10. Contact 11, SRB LH Segment, Wide ETA Stub Hole Spacing.
11. Contact 11, SRB LH Segment, Close ETA Stub Hole Spacing.
12. Contact 26-1, SRB LH Segment, Serial/Part Number.
13. Contact 11, SRB LH Segment, Propellant Profile.
14. Contact 11, SRB LH Segment, Sea Recovery.
15. Contact 11, SRB LH Segment, Sea Recovery.
16. Contact 301, SRB RH Segment, Sea Recovery.
17. Contact 195, SRB RH Segment, Sea Recovery.
18. Contact 292, SRB RH Segment, Sea Recovery.
19. Contact 11, SRB LH Segment, Aft ET Attach Segment.
20. Contact 21-1, RH Aft Segment, Aft Stiff/Aft Dome Joint, View #1.
21. Contact 21-I, RH Aft Segment, Aft Stiff/Aft Dome Joint, View #2.
22. Contact 21-2, RH Aft Segment, Forward Stiffener.
23. Contact 21-3, RH Aft Segment, Stiff/Stiff Joint.
24. Contact 21-4, RH Aft Segment, Aft Stiffener.
25. Contact 21-5, RH Aft Segment, Forward Stiffener.
26. Contact 21-9, RH Aft Segment, Aft Stiffener.
27. Contact 26-1, LH Aft Center Segment, Forward Cylinder.
28. Contact 26-2, LH Aft Center Segment, Forward Cylinder.
29. Contact 131, RH Aft Center Segment, Aft Cylinder Outside View.
30. Contact 131, RH Aft Center Segment, Aft Cylinder Outside Closeup View.
31. Contact 131, RH Aft Center Segment, Aft Cylinder Inside View.
32. Contact 131, RH Aft Center Segment, Aft Cylinder Inside Closeup View.
33. Contact 195, Forward Center Segment, Forward Cylinder.
34. Contact 196, LH Forward Segment, Forward Dome.
35. Contact 214, Case Cylinder Fragment.
36. Contact 292, LH Aft Segment, Aft ET Attach .
37. Contact 301, RH Forward Segment, Aft Cylinder.
38. Contact 325, RH Forward Segment, Aft Cylinder.
39. Contact 433, Aft Center Segment, Forward Cylinder.
40. Contact 433-1 and Contact 635, RH Aft Center Segment, Aft Cylinder and LH Forward Segment, Forward Cylinder.
41. Contact 433-2, RH Aft Center Segment, Aft Cylinder.
42. Contact 468, Forward Segment, Aft Cylinder.
43. Contact 487, Forward Skirt Clevis Joint.
44. Contact 502, Forward Center Segment, Aft Cylinder Outside View.
45. Contact 502, Forward Center Segment, Aft Cylinder, Inside View .
46. Contact 524, Case Cylinder Segment Fragment.
47. Contact 538, RH Forward Skirt.
48. Contact 579, RH Aft Segment, Attach Segment, Outside View.
49. Contact 579, RH Aft Segment, Attach Segment, Inside View.
50. Contact 605, Forward Segment, Forward Cylinder.
51. Contact 615-1A, RH Forward Center Segment, Forward Cylinder.
52. Contact 615-18, RH Forward Center Segment, Forward Cylinder.
53. Contact 615-2, RH Aft Segment, Aft Stiffener .
54. Contact 615-3, RH Aft Segment, Aft Stiffener .
55. Contact 615-4, Case Cylinder Segment.
56. Contact 631, Forward Center or Aft Center Segment, Forward Cylinder.
57. Contact 699, RH Forward Center Segment, Aft Cylinder.

[O235]

58. Contact 711, Forward Dome with Forward Skirt Clevis.
59. Contact 712, RH Aft Segment, Attach Segment, Outside View.
60. Contact 712, RH Aft Segment, Attach Segment, Outside Closeup View.
61. Contact 712, RH Aft Segment, Attach Segment, Inside View.
62. Contact 712, RH Aft Segment, Attach Segment, Inside Closeup View.
63. Contact 5038, Forward Segment, Aft Cylinder.
64. Contact 5039, Case Cylinder.
65. Contact 5124, LH Diagonal Strut.
66. Contact 5126-1, Forward Segment, Aft Cylinder.
67. Contact 5126-2, Forward Segment, Case Cylinder.
68. Contact 5128, Forward Segment, Case Cylinder.
69. Reconstruction of Aft Segment.
70. Contact 26-1, Propellant Burn, Putty Installation.
71. Contact 26-1, Propellant Disposal, Temperature Sensor Installation.
72. Contact 26-1, Propellant Disposal, Water Deluge.

 

LIST OF TABLES

Table I. Summary of Submersibles.
Table II. Identified Hardware Not Recovered.
Table III. Major Assets Used by Task Force.
Table IV. Recovered Hardware-SRM.
Table V. Percentage of Recovered SRM Hardware.

 

LIST OF APPENDICES

Appendix A. Report of Sightings of SRB Hardware.
Appendix B. Addendum I (RH SRB Aft/Dome/Stiffener Segment) to Requirements for 51-L SRB Retrieval Operations.
Appendix C. Plan for Salvage Off-Load and Transport to Storage Facility.
Appendix D. Plan for Propellant Disposal for 51-L SRB Components.

 

[O236] SOLID ROCKET BOOSTER INCREMENTAL RECOVERY PLANNING

I. SCOPE AND INTRODUCTION

A. SCOPE

This section describes the recovery process form the initial planning and identification of Solid Rocket Booster (SRB) components and coordination with the Navy salvage operations through the recovery to the placement of hardware in Hangar "O" or the Explosive Ordnance Disposal (EOD) Range for evaluation. The recovery operation was initiated by searching areas defined by radar tracks provided by the Eastern Space and Missile Center (ESMC) Range Safety organization with use of sonar devices. Sonar contacts were then investigated by manned or unmanned submersibles to determine if the contacts were hardware from the 51-L vehicle and to obtain video/photograhic/audio records for further identification by personnel on shore. Once hardware was determined to be useful to the investigation, plans were generated to recover and transport to shore. Safing operations (propellant disposal) and more definition of the hardware dimensions, features, etc. were then conducted for storage/other evaluation. All recovered hardware has a contact number assigned individually to catalogue each part. For the purpose of consistency, reference to SRB hardware will be by contact number with the control numbers listed in Appendix A of the Search, Recovery, and Reconstruction Team Report. The control numbers and documentation were established by the 51-L Debris Impound Area Group.

 

B. INTRODUCTION

The SRB Recovery Support Team was established to aid in identifying hardware located by the search vehicles. This was accomplished by placing personnel who were knowledgeable of the Shuttle hardware on-board the search vessels for initial identification (SRB, Left Hand, Right Hand, External Tank, etc. ) and by subsequent review of underwater examination records by personnel on shore. Personnel from NASA, Morton Thiokol, Inc. (MTI), USBI Booster Production Co., Inc. (USBI), and Lockheed Space Operations Company (LSOC) served on-board the search and recovery vessels. The support personnel on-board the salvage vessel (Stena Workhorse), including representatives from the ESMC Explosive Ordnance Disposal (EOD) organization, assisted in the salvage operations to ensure safety, hardware preservation, and to maintain evidence of flight anomalies.

Team members also supported the Navy Superintendent of Salvage (SUPSALV) in determining areas for search and priorities for recovery operations. Analysis of telemetry data on 51-L SRB's provided data that the right-hand motor was anomalous. In addition, early photographic and video tracking film evaluation identified the right-hand SRB as having problems. The Task Force therefore declared priorities on the Space Shuttle recovery operations to retrieve the right-hand (RH) SRB, left-hand (LH) SRB, and Orbiter to assist in the accident analysis. Attention was given to the LH SRB for the purpose of obtaining additional information to aid in the evaluation of both factory and field joint performance. In addition to the SRB components, emphasis was given to the recovery of the Orbiter, External Tank (ET), and payload (Inertial Upper Stage (IUS), Tracking and Data Relay Satellite (TDRS)).

Other activities included providing daily status reports to 51-L Investigation Team personnel at MSFC and others (Commission Task Force, news media, etc.). After recovery, team members performed inspections and documented their findings to provide accurate descriptions of the hardware.

The following paragraphs provide a report of the recovery activities performed and document the results of the SRB hardware search and recovery operations.

 

II. DESCRIPTION OF SRB

A. GENERAL

In order to understand the SRB terminology, an understanding of the components assembled on the vehicle is needed. The maneuvers of roll, pitch, and yaw are about the x, y, and z axes, respectively (reference Figure 1). Sitting in the Orbiter and looking forward, the RH SRB is below and to the right. The RH SRB is a mirror image of the LH SRB, therefore, reference datums in addition to the x, y, and z axes were established to maintain uniformity. The zero degree datum for the LH SRB is on the upper center line ( + z axis), and the zero degree datum for the RH SRB is on the lower center line (-z axis).

An SRB is nominally 12 feet in diameter and 149 feet long. The inert weight is 175,000 pounds, and the lift-off weight is 1,300,000 pounds. The SRB system provides the necessary structural support for the Shuttle vehicle on the launch pad, transfers thrust loads to the Orbiter and ET, and provides housing, structural support, and bracketry needed for the recovery system, the electrical components, the separation motors, and the Thrust Vector Control (TVC) system. The SRB systems consist of the forward assembly (forward skirt, frustum, and nose cap), the Solid Rocket Motors (SRM's), and the aft skirt assembly. SRB structural components are planned to be used for 20 flights (reference Figure 2).

Documentation convention stipulates that all vehicles are drawn going from the left (forward) to right (aft) thereby presenting the LH side of the vehicle. Consequently, only the LH SRB is documented; therefore, care must be exercised in reviewing drawings and illustrations to distinguish the RH SRB for the LH SRB.

 

B. SRB SYSTEMS

1. Forward Assembly - The forward assembly consists of the nose assembly, forward ordnance ring, and forward skirt.

a. Nose Assembly - The nose assembly includes the nose cap, the frustum structure, the frustum flotation components, and hardware for attaching the forward separation motors and nose cap thrusters. The nose cap houses both the pilot and drogue parachutes and is separated in-flight from the frustum by three nose cap thrusters. The frustum houses the main parachutes and altitude sensor assembly, provides the structural support for the forward separation motors, and incorporates flotation devices and handling hardware for water recovery.

b. Forward Ordnance Ring -The forward ordnance ring provides a plane of separation between the frustum and the forward skirt assembly. The ring houses the linear-shaped charge (LSC) used in the destruct function.

c. Forward Skirt - The forward skirt is comprised of an SRB/ET attachment fitting which transfers the thrust loads from the SRB to the ET. The forward skirt also has a forward bulkhead which seals the forward end of the skirt. The skirt provides the structure to react parachute loads during deployment, descent and towing. Internal structures are provided for mounting components of the electrical and instrumentation (E&I) subsystem, the rate gyro assembly, range safety panels, and the systems tunnel components. The skirt assembly, at completion of installation, is sealed to provide additional flotation capability.

 

2. Solid Rocket Motor (SRM):

a. Solid Rocket Motor - The SRM is the primary propulsive element for the Space Shuttle providing 563.5 pounds per square inch absolute chamber pressure which is equal to 1.9 million pounds of thrust vacuum. The SRM consists of: an insulated and lined segmented rocket motor case loaded with solid propellant; an ignition system complete with electromechanical safe and arm device, initiator, and loaded igniter; a movable nozzle; raceway bracketry; instrumentation; and the necessary integration hardware.

b. Scructural - The major configurations required to assemble one SRM are a forward rocket motor segment, two center rocket....

 


[
O237]
Figure 1. 51-L Coordinate System.


[
O238]
Figure 2. Solid Rocket Booster Structure.

 

[O239] ....motor segments, and one aft rocket motor segment. Each SRM segment is comprised of two to four components. The joints of the components that are assembled, insulated, lined, and cast at the factory are referred to as factory/plant joints (reference Figure 3). A field joint is that portion of the SRM segment that is assembled/stacked at KSC to create the finished SRM (reference Figure 4). The SRM components and subsystems are physically interchangeable and replaceable. By matching the burning rates of motor segments cast in matched pairs from the same propellant lot and case weights of each segment, the performance, interchangeability, and replaceability between a flight set of SRM's can be maintained.

 

3. Aft Skirt Assembly - The aft skirt provides attach points to the Mobile Launch Platform (MLP) and provides support to the Shuttle on the launch pad for all conditions prior to booster ignition. The aft skirt provides aerodynamic/thermal protection, mounting provisions for the TVC subsystem, and the aft mounted separation motors. The aft skirt provides sufficient clearance for the SRM nozzle at the null position plus full gimbal travel. The aft skirt kick ring provides the necessary structural capability to absorb and transfer induced pre-launch loads.

 

C. SRB SUBSYSTEMS

The subsystems of the SRB are made up of the following:

1) Systems Tunnel
2) SRB/ET Aft Attach Ring
3) TVC subsystem
4) Separation subsystem
5) Recovery subsystem
6) E&I subsystem.

 

1. Systems Tunnel - The SRB systems tunnel, located at the 90° position of each SRB, houses the electrical cables associated with the E&I subsystem and the LSC of the Range Safety System (RSS). The tunnel provides lightning, thermal, and aerodynamic protection and mechanical support for the cables and the LSC.

2. SRB/ET Aft Attach Ring - The SRB/ET aft attach ring is composed of a steel ring and three struts that physically attach the SRB to the ET. These attachments are designed to react to loads in place of the attach ring and allow unrestrained contraction/expansion of SRB or ET in the longitudinal direction (reference Figure 5).

The attach strut assembly provides the physical attachment between the aft ring of the SRB and the ET. The strut incorporates separation devices that release the SRB upon command (references Figures 6 and 7, and Photographs 1 and 2).

3. TVC Subsystems - The TVC, in conjunction with the SRM, provides pitch, roll, and yaw vehicle movements as desired by the Orbiter Guidance, Navigation and Control (GN&C) System. The subsystem, mounted in the aft skirt, consists of two hydraulic power units (HPU's) and two servoactuators. The two HPU's provide hydraulic power to drive the two servoactuators, designated as Rock and Tilt. These servoactuators serve to provide attitude control for each of the SRB's in response to control commands from the General Purpose Computers (GPC's) via flight control electronics in the Orbiter Vehicle (OV). (Reference Photograph 3.)

4. Separation Subsystem - The separation subsystem is designed to ensure safe separation of each of the SRB's from the ET without damaging or recontacting the Orbiter/ET during or after separation. The separation subsystem consists of a release system, sensors, and separation bolts located in the SRB/ET forward attach fitting and in each of the aft attach struts, and eight solid booster separation motors (BSM's)-four mounted in the SRB nose frustum and four mounted externally on the aft skirt. The aft motors are located unsymmetrically, which causes a small roll movement to be imparted to the SRB. The BSM's are located such that the SRB moves from the Orbiter/ET in a way that reduces the plume and particle impingement on the Orbiter. All sequencing and commands are issued by the Orbiter.

5. Recovery Subsystem - The booster recovery subsystem provides the necessary hardware to control the SRB final descent velocity and attitude after separation. The major components of the recovery subsystem are the pilot, drogue and main parachutes. The recovery subsystem includes parachutes, methods of sequencing and deploying these parachutes, parachute separation components, and location aids that help in search and retrieval operations for the expended booster and parachutes.

6. E&I Subsystem:

a. Operational System: The SRB E&I subsystem for operational flights consists of two major functional systems dedicated to two specific portions of the SRB mission. One system is operational from prelaunch until SRB/ET separation and is referred to as the Ascent System. This system consists of the E&I subsystem components necessary to respond to Orbiter vehicle (OV) commands for controlling SRB prelaunch functions, ignition, powered ascent, and SRB/ET monitored. The other system is operational from just prior to SRB/ET separation until SRB splashdown and is referred to as the Recovery System. This system consists of the E&I subsystem components that bring about the successful recovery of the SRB after burnout and separation by performing the following functions:

1) Severance of the nozzle extension
2) Deployment of the drogue and main chutes
3) Powering of location aids
4) Severance of main chute at water impact

The recovery system is simple and self-contained, except for initial POWER ON command, which is derived from the separation fire commands from the OV.

b. RSS: The RSS contains the necessary equipment to destroy the SRB in case of a malfunction requiring premature flight termination. The system is ground operated and redundant. It is monitored, tested, and safed via the Multiplexer-Demultiplexer (MDM) in the forward IEA.

 

III. IDENTIFICATION OF HARDWARE

Shuttle Flight 51-L SRB hardware was initially located on the ocean floor using the Klein sidescan sonar. Search patterns were established based on radar tracking of the Shuttle components. Identification of the sonar contacts was accomplished by manned and unmanned submersibles. Table 1 summarizes these submersibles.

 

TABLE 1.

SUBMERSIBLE

TENDER SHIP

MANNED/ UNMANNED

.

Sea Link JSL I

Edwin Link

Manned

Sea Link JSL II

Seward Johnson

Manned

Nuclear Sub NR-I

Sunbird

Manned

Deep Drone

Independence

Unmanned

 

Contractor and/or National Aeronautics and Space Administration personnel familiar with the flight hardware were on-board the manned submersibles and on-board the tender ship for the Deep Drone. The on-board personnel provided immediate identification of the hardware and pointed out specific identifying characteristics (clevis, tang, serial/part numbers, propellant thickness, inhibitor, etc.) to be recorded on video and photographed. The color video with audio and photographs made onboard the submersibles (no audio with Deep Drone) were then sent ashore for developing, duplicating, and further identification.

 

A. METHOD OF IDENTIFICATION.

As an aid to hardware identification, books containing photographs and illustrations of identifying characteristics were compiled and distributed to team personnel on-board recovery vessels.

The assets used to identify SRB hardware during the search operation are listed below. Identification of parts determined as....

 


[
O240]
Figure 3. SRM Factory/Plant Joints.
Figure 4. SRM Field Joints.


[
O241]
Figure 5. SRB/ET Aft Attach Strut.
Figure 6. SRB/ET Upper Strut Assembly (RH).


[
O242]
Figure 7. SRB/ET Aft Attach Strut.


[
O243]
Photograph 1. Upper and Diagonal Struts.


[
O244]
Photograph 2. Lower Strut (Installed).


[
O245]
Photograph 3. TVC System.

 
 

[O246]...important for recovery by the Recovery Support personnel were prioritized and forwarded to the salvage vessels. A sketch of each piece of hardware was made to assist recovery personnel on the ships to identify attachment points. Calculated weight, center of gravity (e.g.), dimensions, and special notes concerning propellant locations or areas of caution were included.

 

1. Assets

a) Underwater video tape
b) Underwater still photographs
c) Artist renditions of underwater artifacts
d) Radar trajectory plots
e) Sonar cross reference charts
f) NASA Select Press Briefing video tape
g) Land based photographs of recovered hardware
h) Assembly blueprints/sketches
i) Propellant burnback pattern charts
j) Assembly close-out photographs

 

2. Identifying Characteristics

a) Inherently unique pieces
b) Bolt hole sizes (ET stub ring)
c) Pin hole sizes (clevis)
d) Proximity of known hardware (identified pieces to adjacent unidentified pieces)
e) Pin and bolt hole locations
f) Type of joint (factory or field, tang or clevis)
g) Tang index slots (at 0, 118, and 240 degrees)
h) Leak check port location (at 0 degree on tang)
i) Insulation configuration
j) Insulation thickness
k) Inhibitor size and shape
l) Propellant burnback pattern
m) Part and serial number markings (where available)
n) Exterior cork locations
o) Exterior foam locations
p) System tunnel remnants
q) ET attach remnants
r) Stub remnants for ET attach ring
s) Stiffener ring remnants
t) Case wall discoloration patterns
u) Comparison of radar trajectory track to sonar location (latitude and longitude)
v) Scaling known dimensions as a comparison base
w) Paint pattern on forward skirt and frustum
x) BSM location

Figures 8 through 12 and Photographs 4 through 13 are examples of identifying methods.

 

B. ANALYSIS OF VIDEO, AUDIO, AND PHOTOGRAPHS

Video, audio (where provided), and photographs of each contact were analyzed to help identify the hardware. Each video was analyzed for Shuttle element (i.e., Orbiter, SRB, Payload, etc.) by NASA and contractor representatives who were knowledgeable of hardware. These personnel provided the expertise required to assure identification of hardware that was located and filmed. Personnel who served on-board the sea vessels during the search operations also provided aid in identifying and describing the hardware. further analysis was conducted on hardware identified as part of the SRB flight element to provide data for the recovery plan. A list of hardware observed on video is listed in Appendix A.

 

C. HARDWARE IDENTIFIED BUT NOT RECOVERED

During the investigation, hardware of low value to the failure investigation was identified but not recovered and is listed in Table II.

 

IV. RECOVERY PLANS

Recovery plans were prepared and used as a means to obtain authorization for recovery by the Commission Task Force and to provide the requirements for recovery operations to the Salvage Team. These plans were defined based upon hardware criticality to the investigation and safety hazards (primarily to fishermen in shallow water). See Appendix B for a typical plan.

 

A. RECOVERY ASSETS

Assets used in the operation were owned by NASA or owned or leased by the U. S. Navy and were classified into four categories according to task assignment and capability. The categories were:

1) Search
2) Identification
3) Recovery
4) Logistics

Table III identifies each major asset used by the Task Force and includes task assignment and capabilities of each element.

 

TABLE II. IDENTIFIED HARDWARE NOT RECOVERED.

Contact Number

Description

.

21-6

RH Aft Seg Stiffener

21-7

RH Aft Seg Nozzle Part

21-8

RH Aft Seg Nozzle Part

24

LH Aft Seg/Dome/Kick Ring

41

Fwd Seg/Dome/Igniter

345

Case Fragment

417

Case Fragment

504

Fwd Dome/Igniter

632

Case Fragment

5125

Case Fragment (?)


[
O247]
Figure 8. Radar Trajectory Plot.

[
O248]
Figure 9. Forward Segment Burn Back Pattern.

[
O249]
Figure 10. Forward Center Segment Burn Back Pattern.

[
O250]
Figure 11. Aft Center Segment Burn Back Pattern.

[
O251]
Figure 12. Aft Segment Burn Back Pattern.

[
O252]
Photograph 4. SRM Segment Nameplate.

[
O253]
Photograph 5. Contact 26-1, SRM LH Aft Segment, Pressure Port, Tang End.
Photograph 6. Contact 195, SRB RH Segment, Propellant Profile.

[
O254]
Photograph 7. Contact 195, SRB LH Segment, System Tunnel.
Photograph 8. Contact 11, SRB LH Segment, Component Serial/Part Number.

[
O255]
Photograph 9. Contact 11, SRB LH Segment, Propellant Burn Back Pattern.
Photograph 10. Contact 11, SRB LH Segment, Wide ETA Stub Hole Spacing.

[
O256]
Photograph 11. Contact 11, SRB LH Segment, Close ETA Stub Hole Spacing.

[
O257]
Photograph 12. Contact 26-1, SRB LH Segment, Serial/Part Number.
Photograph 13. Contact 11, SRB LH Segment, Propellant Profile.

 

[O258] TABLE III-MAJOR ASSETS USED BY THE TASK FORCE.

Vessel ID

Vessel Type

Task Assignment

Primary Capability

.

Freedom Star

Surface Vessel

Search

Side Scan Sonar

Liberty Star

Surface Vessel

Search

Side Scan Sonar

G.W. Pierce

Surface Vessel

Search

Side Scan Sonar

P.L. III

Surface Vessel

Search

Side Scan Sonar

Seward Johnson w/Sealink II

Surface Vessel w/manned Submersible

Identification Recovery of small items

Underwater Video & Photo Manned Submersible

Edwin Link w/Sealink I

Surface Vessel w/manned Submersible

Identification Recovery of small items

Underwater Video & Photo Manned Sumersible

USS Sunbird w/NR-1

Surface Vessel w/manned nuclear powered Submersible

Identification

Long-Range Capability w/underwater Video and Photo

Independence w/Deep Drone

Surface Vessel w/Remote Operating Vehicle

Identification

Underwater Video

USS Preserver

Surface Vessel

Recovery

Dive Team to 190 Ft.

Stena Workhorse w/Gemini

Surface Vehicle w/Remote Operating Vehicle

Recovery

100-Ton Crane and Underwater Video

LCU

Surface Vessel

Recovery

Dive Team to 150 Ft.

Eliminator

Surface Vessel

Logistics

Logistics Support

Pelican Princess

Surface Vessel

Logistics

Logistics Support

 

B. DEVELOPMENT OF PLAN

In order to control and provide necessary information for salvage planning, a document was prepared for each recovered part identifying:

1) The specific hardware to be recovered
2) Its location
3) Priority
4) Sea vessels to be used
5) Timelines
6) Requirements for safe handling
7) Critical evidence protection and preservation
8) Transport to shore

Individual, self-contained plans including illustrations were generated and approved by Search, Recovery and Reconstruction Team members. Figures 13 through 33 give the rationale used to determine the hardware's location and orientation on the launch vehicle assembly. Photographs 14 through 18 show the recovery operations.

 

C. SAFETY AND HAZARD CONSIDERATIONS

The inadvertent separation of the SRB from the ET occurred prior to the engagement of the Pyro Initiator Circuit (PIC), which controls the deployment of the various pyro devices. All ordnance devices installed on the SRB's were assumed live during retrieval operations and handled with extreme care.

The following guidelines for lifting components from the ocean were established to prevent inadvertent ignition and damage to the recovered hardware.

1. Avoid use of steel hooks or cables which may come in contact with suspected burn through areas.
2. Stabilize part prior to loading on the ship.
3. Tie down parts immediately after loading onto ship.
4. Disarm ordnance.
5. Neutralize forward skirt batteries (for range safety system).
6. Examine hydrazine tanks located in aft skirt for leakage prior to personnel entering SRB area.

 

The following precautions were implemented for the propellant.

1. Keep wet.
2. Do not permit shear between hard surfaces.
3. Do not subject to direct heat/flame.
 


[
O259]

Figure 13. Contact 11. Left- Hand (LH) Attach Segment.
Figure 14. Contact 21-1. RH Aft Segment/Dome/Stiffener.

[
O260]
Figure 15. Contact 21-2. Case Tang Segment.
Figure 16. Contact 21-3. RH Aft Segment Fragment.

[
O261]
Figure 17. Contact 21-4. Aft Segment- Stiffener.
Figure 18. Contact 21-5. Aft Segment- Stiffener Ring Segment.

[
O262]
Figure 19. Contact 21-6. Aft Segment-Stiffener Segment.
Figure 20. Contact 21-7. SRB Aft Segment Stiffener Ring Section.

[
O263]
Figure 21. Contact 21-8. SRB Fragment.
Figure 22. Contact 21-9. Aft Segment-Stiffener.

[
O264]
Figure 23. Contact 24. Left Hand Aft Segment.
Figure 24. Contact 26-1. LH Aft Center Segment, Forward Cylinder.

[
O265]
Figure 25. Contact 26-2. LH Aft Center Segment, Forward Cylinder.
Figure 26. Contact 41. Forward Dome with Igniter.

[
O266]
Figure 27. Contact 195. Section of Factory Joint Tang.
Figure 28. Contact 214. Section of Forward Center Segment.

[
O267]
Figure 29. Contact 292. Section of Field Joint Clevis.
Figure 30. Contact 301. Section of Factory Joint Clevis.

[
O268]
Figure 31. Contact 325. SRB Case Cylinder-Clevis Joint.
Figure 32. Contact 502. RH SRB Cylinder Segment, Field Joint Tang.

[
O269]
Figure 33. Contact 579. Section of Field Joint Clevis.
Photograph 14. Contact 11, SRB LH Segment, Sea Recovery.

[
O270]
Photograph 15. Contact 11, SRB LH Segment, Sea Recovery.
Photograph 16. Contact 301, SRB RH Segment, Sea Recovery.

[
O271]
Photograph 17. Contact 195, SRB RH Segment, Sea Recovery.
Photograph 18. Contact 292, SRB RH Segment, Sea Recovery.

 

[O272] 4. Do not shock/drop.
5. Use sand bags or wood pallets to secure or brace while handling the segments of steel and propellant.
6. Do not place pieces of propellant in contact with each other except during and just prior to actual disposal operation.
7. Loose propellant should not be placed in contact with or on any case segment with propellant attached.
8. Store loose propellant in an approved container.
9. Propellant sensitivity is a function of thickness and porosity following sustained exposure to water.
10. Do not handle AP crystals. Insure that crystal areas are wetted down prior to movement of any propellant.

 

V. DESCRIPTION OF RECOVERED HARDWARE

A summary listing of all SRM hardware, including information relative to identification and location, is shown on Table IV. Due to the lack of identifying features, some parts could not be identified to the extent necessary to determine exact location on the SRB. A description of each part is provided on the following pages. Table IV summarizes the recovery hardware.

CONTACT#11 - This was the first SRB part recovered. The part was identified as a large fragment of the ET attach segment, aft segment, LH SRB. Identification was made by propellant profile analysis, hole patterns on the attach stubs, and electrical connector part numbers. The part contained both attach stubs, a tang and clevis, and a fragment of the forward stiffener segment which was attached to the tang. Approximately 80 % of the interior surface was covered with propellant. (Reference Figures 34 and 35, and Photograph 19. )

CONTACT#21-1 - This part was identified as fragments of the aft dome, aft stiffener segment, and kick ring, RH SRB. This part was identified by the part number and serial number found on the exterior surface of the part. This was a very large part and was significant in providing a base for reconstruction of the RH SRB aft segment. There was no propellant on this piece. (Reference Figure 36 and Photographs 20 and 21.)

CONTACT#21-2 - This part was identified as a RH forward stiffener segment and was identified by dimensional analysis which proved that the part matched with Contact 21-3. Contact 21-3 was positively identified as RH SRB. A factory clevis with a missing outer leg, the inactive and forward stiffener stubs, and a factory joint tang were the major design features contained on this part. There was no propellant on this part. (Reference Figure 37 and Photograph 22).

CONTACT#21-3 - This part has been identified as a fragment of the forward stiffener segment, aft segment, RH SRB. The part was identified by part number (IU50715-02) and serial number (0000002R2) found on exterior surface. Major features of this part are a clevis with the outer leg broken off and a portion of the systems tunnel. There is no propellant on the part. (Reference Figure 38 and Photograph 23.)

CONTACT#21-4 - This part has been identified as a fragment of the aft stiffener segment, aft segment, RH SRB. It was identified by the part number and serial number found on the part. Major features of the part are a field joint clevis and a stiffener ring stub. There is no propellant on the part. (Reference Figure 39 and Photograph 24.)

CONTACT#21-5 - This part is a fragment of RH aft segment, forward stiffener segment, containing the inactive stiffener stub and the active forward stiffener ring stub. The part mates with Contact 21-3 which was identified as RH SRB by a serial number. It was located laterally on the aft segment by the leak test port at 0° on the clevis. There is no propellant on this piece. (Reference Figure 40 and Photograph 25.)

CONTACT#21-9 - This part was identified as a fragment of the RH stiffener segment by part number (IU50715) and serial number (OOOOOO1R2) found on the exterior surface. The outer surface is heavily sooted except where foam residue is present. A factory clevis and factory tang are present on the piece. The piece contained no propellant. There is no evidence of heat damage on either the clevis or tang. (Reference Figure 41 and Photograph 26.)

CONTACT #26-1 - This part has been identified as the forward cylinder of the aft center segment, LH SRB. It was identified by a serial number found on the part. Major features of the part are a factory joint tang and systems tunnel floor plate fragments. The interior surface is covered with propellant. There are no apparent indications of leakage or other abnormal appearance. (Reference Figure 42 and Photograph 27.)

CONTACT #26-2 - This part was identified as a fragment of the forward cylinder, aft center segment, LH SRB. Identification was made as a result of dimensional analysis which proved that the part physically mates with Contact 26-1 at the fracture surface. Contact 26-1 was identified by serial number and part number found on the exterior surface. The interior surface of Contact 26-2 was covered with propellant. No anomalous performance features were noted on the part. (Reference Figure 43 and Photograph 28.)

CONTACT #131 - This part was identified as RH SRB aft cylinder of the aft center segment. Part number (IU50717-02) and serial number (0000060RI) were found on the exterior surface of the part. The location of the burned out area found on the part was consistent with photographic data (294 to 316). Circumferential location was determined by discovery of the 0° alignment slot on the tang. There is propellant over approximately 90 % of the surface. This part was considered a very significant finding since it is a part of the suspected burned through joint. (Reference Figures 44 through 52, and Photographs 29 through 32.)

CONTACT#195 - This part has been identified to be a section from the forward case cylinder, forward center segment, LH. The conclusion was based upon the geometry of the part which included propellant profile, plant joint tang, and field joint clevis. The tang thickness measurements were taken and favorably agreed with the manufacturing records. No anomalous performance indications were noted. (Reference Figure 53 and Photograph 33.)

CONTACT #196 - This part was identified as LH forward dome by part number (IU51473-01) and serial number (0000035) found on the part. The exterior surface is heavily sooted. No propellant was present. Insulation is present over 100% of the interior surface. (Reference Figure 54 and Photograph 34.)

CONTACT #214 - This part is a fragment of case cylinder with a factory tang and field clevis. No further identification could be made due to lack of additional identifying features. The outside surface is lightly sooted. There is propellant over approximately 60 % of the interior surface. (Reference Figure 55 and Photograph 35 )

CONTACT #292 - This part was identified as a fragment of the RH ET attach segment, aft segment. Identification was based upon comparison of the propellant profile of the part with the propellant profile on Contact #11 which is a known LH SRB attach segment part. This part was of particular interest since it contains a section from the suspect failure field joint. However, other than having a heavily-sooted appearance, no apparent indication of anomalous performance was noted. (Reference Figures 56 and 57, and Photograph 36.)

CONTACT#301 - This part was identified to be a large fragment from the aft case cylinder of the RH forward segment. Identification was made from part number and serial number found on the exterior surface. The part contains a plant joint (clevis) and field joint (tang). No anomalous performance indications were found on the hardware. (Reference Figure 58 and Photograph 37.)

CONTACT #312 - FRUSTUM SHEAR BEAM-Two fragmented pieces of frustum shear beam were recovered. These were identified by their shape and components that were attached.

 

[O273] TABLE IV 51-L SRM RECOVERED HARDWARE.

Target

Title

Joint

ID Method

.

1

L. H. Aft Seg, ET Attach

Clevis Field & Tang Factory

Propellant Profile & Connector P/N

21-1

R. H. Aft Seg, Aft Stiffener/Aft Dome

Clevis Factory & Tang Factory

Part No. & Serial No

21-2

R. H. Aft Seg, Fwd Stiffener

Clevis Factory & Tang Factory

Mates with 21-3

21-3

R. H. Aft Seg, Fwd & Aft Stiffener

Clevis Factory

Part No. & Serial No

21-4

R. H. Aft Seg, Aft Stiffener

Clevis Factory

Part No. & Serial No

21-5

R. H. Aft Seg-Fwd Stiff

Clevis Factory & Tang Factory

Mates with 21-3

21-9

R. H. Aft Seg, Aft Stiffener

Clevis Factory & Tang Factory

Part No. & Serial No

26-1

L. H. Aft Ctr, Fwd Case Seg

Tang Factory

Part No. & Serial No

26-2

L. H. Aft Ctr, Fwd Case Seg

Clevis Field

Mates with 26-1

131

R. H. Aft Ctr Seg, Aft Cylinder

Tang Field

Part No. & Serial No

195

L. H. Fwd Ctr Seg, Fwd Cylinder

Clevis Field & Tang Factory

Tang Thickness Measurements

196

L. H. Fwd. Seg Dome

Tang Factory/Field

Part No. & Serial No

214

Ctr Seg, Fwd Cyl (Light Wt.)

Clevis Field & Tang Factory

Unidentifiable

292

R. H. Aft Seg-ET Attach

Clevis Field

Propellant Profile- Diff to L. H.

TABLE IV 51-L SRM RECOVERED HARDWARE-Continued

Target

Title

Joint

ID Method

.

301

R. H. Fwd Seg, Aft Cyl.

Clevis Factory & Tang Field

Part No. & Serial No.

325

R. H. Fwd Seg Aft Cyl

Clevis Factory

Insulation Erosion Pattern

433

Aft Ctr Seg, Fwd Cylinder

Clevis Field

Inhibitor Height

433-1

R. H. Aft Ctr Seg, Aft Cylinder

None

Mates with 433-2

433-2

R. H. Aft Ctr Seg, Aft Cylinder

Tang Field & Clevis Factory

Mates with 131

468

Fwd Seg, Aft Cyl

Clevis Factory & Tang Field

Propellant Burn Back Pattern

487

Forward Skirt Clevis

Clevis

Holes Spaced at 1°/ Crotch Seal

502

R. H. Fwd Ctr Seg, Aft Cyl

Tang Field

Part No. & Serial No.

524

Case Cylinder

None

Unidentifiable

538

R. H. Fwd Skirt

N/A

Paint Pattern

579

R. H. Aft Seg, ET Attach

Clevis Field & Tang Factory

Part No. & Serial No.

605

Fwd Seg, Fwd Cylinder

Clevis Factory

Insulation Buildup at Clevis

615-3

R. H. Aft Seg, Aft Stiffener

None

Mates with 21-1 & 21-4

 

[O274] TABLE IV. 51-L SRM RECOVERED HARDWARE-Continued

Target

Title

Joint

ID Method

.

615-4

Small Piece-Case

None

Unidentifiable

615-1A

R. H. Fwd Ctr Seg, Fwd Cyl

Tang Factory

Mates with 615-2

615-1B

R. H. Fwd Ctr Seg, Fwd Cyl

Clevis Field

Mates with 615-1A

615-2

R. H. Fwd Ctr Seg, Fwd Cyl

Clevis Field

Part No. & Serial No

631

Ctr Seg, Fwd Cyl

Clevis Field & Tang Factory

Unable to Identify L.H. or R.H.

635

L. H. Fwd Seg Fwd Cylinder

Clevis Factory

Tang Thickness Measurement

699

R. H. Fwd Ctr Seg, Aft Cylinder

Clevis Factory & Tang Field

Part No. & Serial No.

711

Fwd Dome

Fsd Skirt Clevis

Design Features

712

R. H. Aft Segment, ET Attach

Tang Field

Rework on Attach Ring

5038

Fwd Seg, Aft Cyl

Clevis Factory

Propellant Burn Back Pattern

5039

Case Cylinder

Tang - Unknown Field/Factory

Unidentifiable

5124

L. H. ET/SRB Diagonal Strut

None

Serial Number

5126-1

Fwd Seg, Aft Cyl

Clevis Factory

Propellant Burn Back Pattern

5126-2

Fwd Seg, Aft Cyl

None

Wall Thickness

5128

Fwd Seg, Case Cyl

Tank - Unknown Field/Factory

Wall Thickness


Figure 34. Contact 11, LH ET Attach Segment

[
O275]
Figure 35. Contact 11, LH ET Attach Segment.
Photograph 19. Contact 11, SRB LH Segment, Aft ET Attach Segment.

[
O276]
Figure 36. Contact 21-1, RH Aft Case Segment, Aft Stiff/Aft Dome Joint.
Photograph 20. Contact 21-1, RH Aft Segment, Aft Stiff/Aft Dome Joint, View #1.

[
O277]
Photograph 21. Contact 21-1, RH Aft Segment, Aft Stiff/Aft Dome Joint, View #2.
Figure 37. Contact 21-2, RH Aft Segment, Forward Stiffener.

[
O278]
Photograph 22. Contact 21-2, RH Aft Segment, Forward Stiffener.
Figure 38. Contact 21-3, RH Aft Segment, Stiff/Stiff Joint.

[
O279]
Photograph 23. Contact 21-3, RH Aft Segment, Stiff/Stiff Joint.
Figure 39. Contact 21-4, RH Aft Segment, Aft Stiffener.
 

[
O280]
Photograph 24. Contact 21-4, RH Aft Segment, Aft Stiffener.
Figure 40. Contact 21-5, RH Aft Segment, Forward Stiffener.
 

[
O281]
Photograph 25. Contact 21-5, RH Aft Segment, Forward Stiffener.
Figure 41. Contact 21-9, RH Aft Segment, Aft Stiffener.

[
O282]
Photograph 26. Contact 21-9, RH Aft Segment, Aft Stiffener.
Figure 42. Contact 26-1, LH Aft Center Segment, Forward Cylinder.

[
O283]
Photograph 27. Contact 26-1, LH Aft Center Segment, Forward Cylinder.
Figure 43. Contact 26-2, LH Aft Center Segment, Forward Cylinder.

[
O284]
Photograph 28. Contact 26-2, LH Aft Center Segment, Forward Cylinder.
Figure 44. Contact 131, RH Aft Center Segment, Aft Cylinder Dimensional Outside View.

[
O285]
Figu