[N1] Signatures of subteam members.

I. EXECUTIVE SUMMARY.

II. APPOINTMENT/TEAM CHARTER.

III. ORGANIZATION.

IV. ACRONYMS.

V. PHOTOGRAPHIC, VIDEO, AND TELEMETRY DESCRIPTION AND ANALYSIS.

A. Introduction.

B. Systems Description.

C. Incident Integrated Timeline.

D. Special Analysis.

E. Other Observation.

VI. FINDINGS AND CONCLUSIONS.

A. Introduction.

B. Findings.

C. Lessons Learned.

D. Conclusions.

APPENDIX A.

[N3] EXECUTIVE SUMMARY.

The Photo and TV Support Team was established to analyze and document STS 51-L photography and video products. Results were made available to the Failure Analysis Team for use in evaluating failure scenarios. The Photo Team consisted of subteams at Johnson Space Center (JSC), Marshall Space Flight Center (MSFC) and Kennedy Space Center (KSC) that represented the imagery working elements of those Centers and included an independent team leader and a deputy.

The results of the Photo and TV Support Team activities are documented in this comprehensive report, the core of which is the STS 51-L Incident Integrated Events Timeline developed by the team to correlate imagery and telemetry events. This report describes the significant observed anomalies and related events of the STS 51-L accident and includes image enhancement results which were used to identify, locate, and determine time-related characteristics of the events. Conclusions and findings for follow-up efforts are included. A video tape showing significant events was prepared as in interim report. An updated tape is planned which will reflect the final results and will include voice annotation and pictures of selected recovered hardware.

The KSC photographic and TV system consists of 108 film and 69 TV cameras. For this investigation, approximately 13 million frames of imagery were evaluated, including films from previous flights. Additionally, films from private citizens and news media were made available to the team; this help was very much appreciated and letters of appreciation were sent to the contributors.

Although only a few of the events which were analyzed proved to be significant to the investigation, the analysis of the events was vital in establishing the cause of the STS 51-L incident. The primary anomalous events seen in the imagery are the early smoke and later flame issuing from the aft field joint of the right Solid Rocket Booster (SRB). All other anomalous events are the result of the failure indicated by these primary events.

Analysis of the smoke at lift-off was a combination of establishing the probable location, duration and dynamic characteristics of the smoke source. The source was determined to be at or near the aft field joint of the right SRB and circumferentially at approximately 300. This location was inferred geometrically from multiple camera locations since the source was not in the field of view of any camera. Image analysis also established that smoke first appeared at 0.678-second mission elapsed time (MET) and was last visible at 3.375 seconds MET. Frequency of the individual puffs was established (3 to 5 Hz) for comparison with overall vehicle dynamics.

There is no further evidence of the leak until 58.762 seconds MET, when an initially flickering, then steady flame was observed emanating from the right SRB. Photo analysis established its location to be the aft field joint in approximately the same location as the earlier smoke. Flicker frequency was determined to be approximately 10 Hz. (Note: Recovered right SRB hardware shows a burn through at this joint extending from 294° to 316°.)

Dimensions of the leak plume were estimated from the films and were used to support wind tunnel tests to characterize vehicle aerodynamics. Results of these tests were useful for trajectory reconstruction and also helped to explain the observed plume recirculation patterns.

Film analysis also determined the location of the impingement of the SRB leak plume on the External Tank (ET) and the effect of the plume of the resulting liquid hydrogen (LH₂) leak. Film analysis showed the aft end of the right SRB separating from the ET. Geometric analysis of this motion indicates contact of the forward end of the right SRB and the ET intertank area. Finally, details of vehicle breakup and post-breakup characterization of the right SRB were determined. Since telemetry ceased at approximately 73 seconds, imagery and recovered hardware constituted the only evidence of the final destruction of the vehicle.

The activities of the team included analysis of closeout photography of the aft field joint where an initial review had indicated a possible O-ring flaw. Enhancement and mensuration of the film explained the observations and eliminated the concern of an O-ring flaw prior to mating.

In addition to these conclusions and findings, several important lessons were learned during this investigation. The imagery collected as a result of the clear-day weather was very significant in the accident analysis efforts. Had it been a night launch or a launch with an overcast sky, the amount of time required to reach the conclusions drawn would have been much greater and perhaps never as clearly: understood. Therefore, launch visibility for photographic reasons should be a primary mission rule until the hardware fixes resulting from this investigation are proved operational.

There is a need for better intercenter and intracenter organization of the photo and TV analysis to support both normal launches and contingency operations. Additionally, camera failures on launch day prevented a clear view of the hardware failure point. More and better cameras are required. Additionally, a review of the types of film used to better aid photo enhancement activities is required. A total review of the requirements for imagery and analysis methodology with a goal of improving imagery acquisition, processing, analysis, and archiving is required.

There is a requirement for the Space Transportation System (STS) program to charter an intercenter photographic/TV working group to document the activities required to implement the findings and conclusions of this report.

[N4] II. APPOINTMENT/TEAM CHARTER.

The following letter and its attachment establish the Photography and Television Support Team and appoint the Team Lead.

March 20, 1986

51-L DATA AND DESIGN ANALYSIS TASK FORCE

TO:	D. Germany
FROM:	Task Force Chairman
SUBJECT:	Appointment of Lead, Photo and TV Support Team
1. By letter of March 11, 1986, Attachment I, the Acting Administrator delegated to me, as Chairman of the 51-L Data and Design Analysis Task Force, the power to designate individuals and teams required to support the Task Force. By the same letter, he also delegated to me the power to establish procedures for organization and operation. 2. Pursuant to the delegation, I hereby establish the Photo and TV Support Team of the Task Force and designate you to be the Lead for that Team. The duties, functions and responsibilities of the Team are stated in Attachment 2. 3. As Team Lead, it will be your responsibility: a. To assign tasks to Team members and coordinate their efforts. b. To delegate authority to the Deputy Lead to act for you as you see fit with or without you being present at the Team's regular office at KSC. The Deputy Lead will be designated to me or the Vice Chairman. c. To coordinate the Team's activity with other Team Leads in areas of mutual interest. d. To consult with the Task Force Vice Chairman on a regular basis on all mutual interests. e. To prepare, for consideration and approval by the Task Force, documents that memorialize in appropriate formats, the facts and analysis in the Team's assigned area.
Richard H. Truly

Attachments 2

TO:	M/Chairman, STS 51-L Data and Design Analysis Task Force
FROM:	A/AD/Acting Administrator
SUBJECT:	Establishment of the STS 51-L Data and Design Analysis Task Force
REF:	Memorandum to M/Associate Administrator for Space Flight from AD/A/Acting Administrator, Subject: Formation of the STS 51-L Data and Design Analysis Task Force, dated February 5, 1986

1. Pursuant to the above reference, the STS 51-L Data and Design Analysis Task Force was created to replace the interim Mishap Investigation Board and to support the activities of the Presidential Commission on the Space Shuttle Challenger accident established pursuant to Executive Order 12546 dated February 3, 1986. The Task Force is established in accordance with NMI 8621.1D and is directed to proceed with the analysis of the facts, circumstances, and design issues surrounding the accident in accordance with the then existing plan and personnel. The purpose of this memorandum is to finalize Task Force membership and responsibilities and establish the powers and responsibilities of the Task Force Chairman.

2. Task Force membership is as set forth in Attachment A.

3. The Task Force is responsible for the following:

(a) Determine, review, and analyze the facts and circumstances surrounding the launch of STS Mission 51-L.

(b) Review all factors relating to the accident determined to be relevant including studies, findings, recommendations, and other actions that have been or may be undertaken by the program offices, field centers, and contractors involved.

(c) Examine all other factors which could relate to the accident including design issues, procedures, organization, and management factors.

(d) Utilize the full required technical and scientific expertise and resources available within the NASA institution and those which are or can be made available to NASA.

(e) Document Task Force findings and determinations and conclusions derived therefrom.

(f) In accordance with procedures established jointly with the Presidential Commission, provide information and documentation to the Commission regarding all the above or any other aspect of Task Force activities.

4. The Chairman of the Task Force is delegated the following powers and is assigned the following responsibilities:

(a) Establish such procedures for the organization and operation of the Task Force as he finds most effective; such procedures shall be part of the Task Force records.

(b) Establish procedures to assure the execution of his responsibilities in his absence.

(c) Direct or require the conduct of special tests or additional research as needed in support of the investigation.

(d) Designate such subgroups, teams, representatives, consultants, experts, liaison officers, observers, or other individuals, as required to support the activities of the Task Force. Their duties and responsibilities shall be included as part of the Task Force records.

(e) Coordinate the activities of the Task Force with the Presidential Commission in accordance with procedures established by the Commission.

(f) In coordination with the NASA Director of Public Affairs develop a policy for the appropriate review and dissemination of information to the public concerning the Space Shuttle Challenger accident and the activities of the Task Force.

(g) Advise the Administrator concerning the organization, procedures, operations, and findings of the Task Force, and its associated activities as required.

5. All elements of NASA will cooperate with the Task Force and provide full support within their areas of responsibility.

6. By separate action, I am directing the Associate Administrator for Space Flight, consistent with the final report of the Presidential Commission, to undertake through the regular Office of Space Flight organization such reviews, studies, and supporting actions as are required to develop recommendations to me on corrective measures to be taken prior to the next STS mission with respect to hardware, operational procedures and other aspects of the STS program.

William R. Graham

Acting Administrator

[N5] ATTACHMENT A

The following personnel are appointed to memberships on the 51-L Data and Design Analysis Task Force.

Rear Admiral Richard H. Truly, Chairman (Associate Administrator for Space Flight)

Mr. James R. Thompson, Vice Chairman (NASA Headquarters)

Mr. Robert Crippen (NASA Astronaut, JSC)

Col. Nathan Lindsay (Commander, AF Eastern Space and Missile Center)

Dr. Joseph Kerwin (Director, Space and Life Sciences, JSC)

Dr. Walter Williams (Special Assistant to the NASA Administrator)

Mr. Thomas Lee (Deputy Director, MSFC)

Mr. Clay McCullough (Manager, Support Equipment and Logistics Office, JSC)

Mr. Thomas Utsman (Deputy Director, KSC)

Col. Robert Bourne (Director, AF Space Shuttle Operations, VAFB)

Mr. Alton Jones (Director of Flight Assurance. FSFC)

Mr. John Thomas (Manager, Spacelab Program Office, MSFC)

Mr. Tommy Holloway (Chief, Flight Director Office, JSC)

Mr. Harold Draughon (Manager, Mission Integration Office, JSC)

Mr. Edward F. Parry (Chief Counsel, KSC) will serve as Legal Counsel to the Task Force. Mr. Jay F. Honeycutt (Deputy Manager of Operations and Integration Office, JSC) will serve as Task Force Staff Officer in NASA Headquarters.

Attachment 2

GENERAL ASSIGNMENTS FOR PHOTO AND TV SUPPORT TEAM

The Photo and TV Support Team shall perform as a priority task the end to end 51-L Mission Photography and Video products analysis. The results of these analyses are to be documented and provided to the four Task Force teams that have Commission Panel counterparts. These results will be designed to assist these teams in their efforts to respond to the needs and interests of the Commission. All photographic and TV products will be cataloged, analyzed, and documented.

This Team will serve as the focal point for all of the task force efforts concerning photography and TV including any required enhancement areas.

All requests for photographic and TV products will be handled by this Team. The other Task Force Teams will forward their tasks for photographic and TV data to this team for action.

The Team will assist the Commission panels as required with proper coordination with the interested Task Force Team.

The Team will establish a total photographic and TV plan for support of the task force and commission efforts.

Reporting will be in accordance with Task Force procedures and as required by the Task Force Chairman or Vice Chairman.

III. ORGANIZATION

Figure 1 shows the organization of the Photography and Television Support Team in relation to the STS 51-L Data and Design Analysis Task Force. The figure also lists the number of full-time personnel involved at the NASA Centers and at other processing and enhancement facilities.

IV. ACRONYMS

AGC	automatic gain control
APU	auxiliary power unit
BET	best estimate of trajectory
CAD	computer-aided design
CCD	charge coupled device
CCR	camera control repeater
CTC	camera timing and control
CZR	ribbon frame cameras
DCU	decimal counting unit
DEMUX	demultiplexer
ECC	emergency camera control
EIU	engine interface unit
EPRCO	Exxon Production Research Company
ET	external tank
ETR	Eastern Test Range
FM	frequency modulated
FR	firing room
FSS	fixed service structure
GMT	Greenwich mean time
GMTLO	lift-off in GMT
GPC	general-purpose computer
GUCP	ground umbilical carrier plate
HPFTP	high-pressure fuel turbopump
HDP	holddown post
Hz	Hertz
IRIG	Inter-Range Instrumentation Group
IGOR	intercept ground optical recorder
IFLOT	intermediate focal length optical tracker
IEA	integrated electronics assembly
JPL	Jet Propulsion Laboratory
JSC	Lyndon B. Johnson Space Center
KSC	John F. Kennedy Space Center
[N6] LC	launch complex
LCC	Launch Control Center
LED	light-emitting diode
LIPS	Library of Image Processing Subroutines
LMSC	Lockheed Missiles and Space Corporation
LOA	launch operations area
LOV	limit of visibility
LPS	launch processing system
MCC	Mission Control Center
ME	main engine
MEC	master events controller
MET	mission elapsed time
MIGOR	mobile intercept ground optical recorder
MILA	Merritt Island Launch area
MLP	mobile launch platform
MPS	main propulsion system
MSFC	Marshall Space Flight Center
MTU	master timing unit

MUX	multiplexer
NC	normally closed
NIP	network interface processor
NO	normally open
NPIC	National Photographic Interpretation Center
ODRC	Orbiter Data Reduction Complex
OMS	orbital maneuvering subsystem
OTV	operational television
PA-DD	photographic acquisition-disposition document
PAO	Public Affairs Office
PCM	pulse-code-modulation
PDL	Ponce De Leon
PIC	pyrotechnic initiator capacitor
PM	phase modulated
PPS	pulse-per-second
PSF	pounds per square foot
PRD	Program Requirements Document
PTCR	pad terminal connection room
RCS	reaction control system
RF	radio frequency
RSS	rotary service structure
ROTI	recording optical tracking instrument
RGA	rate gyro accelerometer
RSLS	redundant set launch sequencer
RZ	return to zero
SOP	software operation program
SRB	solid rocket booster
SRM	solid rocket motor
SSME	Space Shuttle main engine
STS	Space Transportation System
T-0	time of mission start, SRB ignition command
TCC	tracker control cabinet
TDRS	tracking and data relay satellite
TMS	trend monitoring system
TSM	tail service mast
TTU	timing terminal unit
TV	television
TVC	thrust vector control
UCS	universal camera sites
USAF	United States Air Force
VAB	vehicle assembly building
VAST	Visual Analysis Support Team
WPAFB	Wright Patterson Air Force Base

V. PHOTOGRAPHIC, VIDEO, AND TELEMETRY DESCRIPTION AND ANALYSIS.

A. INTRODUCTION

This section of the report provides the combined summary results of the photographic analysis teams from the Lyndon B. Johnson Space Center, the John F. Kennedy Space Center, and the Marshall Space Flight Center. Included in this section is a description of the photographic and video systems in place at KSC and the enhancement analysis systems used by the JSC and MSFC photographic analysis teams. The STS 51-L integrated timeline is included. It was developed utilizing the JSC and MSFC evaluation teams in conjunction with the photographic teams at the three Centers. The timeline depicts the events as derived from the available telemetry and photographic data. The special analysis section provides the summary results of the analysis performed on selected photographic data which support the analytical and testing effort being performed by the primary task force teams.

B. SYSTEMS DECRIPTION.

1. Photo-Optical System Description

This section briefly describes and outlines the operational capabilities of the launch operations area (LOA) photo-optical system used at KSC. The subsystems that make up the LOA photo-optical system are listed in the following table.

2. Launch Complex 39/B/MLP-2 Photo-Optical Description

a. Background

The Launch Complex (LC)-39 photo-optical system was conceived in the early days of the Apollo Program in 1963. During the intermediate years of the mid-sixties, the systems design evolved, and installation was complete for the first of the Saturn V launches. The system was an advanced state-of-the-art system at the time.

Although many elements of the system have been upgraded over the years due to unavailability of original parts, and to take advantage of obvious equipment advances, the system is basically the same system.

Since the Shuttle vehicle and ground systems configurations are entirely different from that of the Apollo, the camera locations are different. This is much more apparent around the proximity of the launch mount than it is at the perimeter camera sites.

Photographic coverage of the Shuttle launch vehicle has been implemented per requirements in the Program Requirements Document (PRD) and supported per the Photographic Acquisition-Disposition Document (PA-DD) by the Photographic contractor.

The cameras, environmental housings, most of the mounting hardware, blast covers, and close-in trackers are basically unchanged and have been highly successful thus far in the Shuttle Program.

[N7] b. Photo-Optical System Functions

One of the most important functions of photo-optical systems is to obtain contingency data, particularly to support detail studies of complex event development, and to detect anomalies.

The LC-39 Pad A and B photo-optical system is designed to command and control the remote operation of an extensive array of engineering and documentary film cameras.

Image data are obtained during prelaunch, flight readiness firing, and launch operations for the study and analysis of ground and flight vehicle systems performance.

Engineering applications include high-speed photography of events such as rocket engine ignition sequences, vehicle release mechanisms, mechanical displacements, and vehicle position and attitude during lift-off.

A wide variety of photographic analysis is performed such as detection and identification of flying debris, physical condition of external surfaces, and correlation of lift-off sequences. In addition to the engineering applications, the system also provides a wide variety of still, rapid sequence, and motion picture cameras for press release, multi-media audiovisual applications, and historical record.

c. Outline Description of System

The system control is located in the Launch Control Center (LCC), and incorporates the capability of sequencing up to 160 cameras on each launch pad, including the Mobile Launcher Platform, and the Fixed Service Structure (FSS).

At T-3 minutes, the sequencer is activated and initiates an independent parallel countdown to the Launch Processing System (LPS) countdown, with hold and resume count capability.

At the programmed times, camera start signals are multiplexed and sent to the launch pad, where they are demultiplexed and combined with camera running power and time correlation signals. Distribution to individual cameras is made through repeaters which are centrally located near major camera sites.

d. System Support Subsystems

In addition to the cameras, the system is composed of all the associated hardware and equipment such as mounting pedestals, platforms, brackets, and includes special plates, wedges, and adapting devices.

Also included in the support subsystems are the service cables, purge lines, environmental housings, blast covers, pan-and-tilt units, and dovetail quick-release mounts. Remote controls for close-in tracking of initial flight are also a part of the system.

The major equipment in the control system includes patch panels, timing terminal units, camera control repeaters, system sequencer, emergency camera controls, purge panels for safety and window purge multiplexer and demultiplexer (mux and demux) units, data modems, and camera control cabinets.

e. The 51-L Photo-Optical System Configuration

(1) Perimeter Sites

Figure 2 shows an aerial view of Pad 39-B showing perimeter camera sites.

Figure 3 shows a typical Perimeter Camera Site, specifically Site 4. The figure has been provided for a better understanding of the detailed site data contained in tables 1 through 5.

Figure 4, a general view of an LC-39B Perimeter Camera site is included to show the relationship of the camera locations contained in tables 1 through 5 to the Shuttle vehicle. The camera locations are relative to the vertical axis of the external tank in the launch position.

There is no Site 5 due to the presence of the slide wire installation.

Table 6 shows the displacement of each camera location from the site bench marks shown in tables 1 through 5.

(2) Fixed Service Structure and MLP-2

The cameras located in the Fixed Service structure and MLP-2 are precisely located on figures 5 and 6. Table 7 provides the viewing angles and coordinate locations for each of these cameras with reference to the X and Y axes of the external tank in the launch position.

f. Engineering Description of the System

A detailed engineering description of the LC-39 photo-optical system is provided as an appendix to this report.

2. Tracking Camera Coverage

Shuttle photographic tracking coverage utilizes a series of cameras located outside the pad perimeter which provide coverage from prior to ignition until after SRB separation or until LOV (Limit of Visibility).

Also, at ignition, cameras are started at three off-complex IFLOT (Intermediate Focal Length Optical Tracker) tracking mounts. These mounts are located at Universal Camera Sites (UCS) north, west and south of the launch pad at distances of 3 to 7 miles. These mounts have 16mm and 70mm cameras for coverage of early flight. Although they do provide coverage at lift-off, the lenses are not in proper focus until the vehicle has reached an altitude of approximately 1200 feet. Another mount located 3 miles southeast of the pad provides 70mm coverage of lift-off through the roll maneuver for broadcast-release television.

The long-range tracking instruments are mounted on mobile trailers or stationary units and are linked to the ETR radar and ranger computer. They are identified by type of mount:

MIGOR - Mobile Intercept Ground Optical Recorder

IGOR - Intercept Ground Optical Recorder

ROTI - Recording Optical Tracking Instrument

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[N8]

Figure 3. Typical Perimeter Camera Site.

Figure 4. General view of 51-L at Pad B.

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[N9]

Table 1. LC-39B Perimeter Site 1 Camera Locations.

Table 2. LC-39B Perimeter Site 2 Camera Locations.

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[N10]

Table 3. LC-39B Perimeter Site 3 Camera Locations.

Table 4. LC-39B Perimeter Site 4 Camera Locations.

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[N11]

Table 5. LC-39B Perimeter Site 6 Camera Locations.

Table 6. Dimensional Offsets of Perimeter Camera Stations Except CZR's With Reference to the Benchmarks.

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[N12]

Figure 5. Location of Cameras on LC-39B Fixed Service Structure (51-L Configuration).

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These instruments utilize 35mm or 70mm cameras coupled to lenses with focal lengths ranging from 100 to 500 inches. These lenses are auto-focus and temperature compensated. The locations of the cameras are shown in figure 7.

Coverage by these instruments is from first-acquisition until LOV. Two mounts are located north and two mounts south of the flight line at distances of 6 to 40 miles. Two of these mounts (one north, one south) track the Orbiter after SRB separation. The other two mounts track the SRBs after separation until LOV.

All of the above cameras are dedicated to viewing structural integrity, propulsion performance and possible flight anomalies of the launch vehicle during daylight hours (sunrise plus 45 minutes, sunset minus 45 minutes).

In the event of a launch being scheduled beyond this daylight period, exposure levels are adjusted to "flame exposure," thereby providing coverage of the propulsion plumes.

In addition, all tracking coverage is dependent upon weather conditions and cloud coverage at time of launch.

3. Video System Description

a. Requirements

The design criteria for the pad B MLP-2 and MLP-3 operational television (OTV) systems were defined by station set 81 and the pad A and MLP-1 OTV systems design. MLP-2 was to duplicate MLP-1, and MLP-3 was to duplicate MLP-2. The pad B OTV system was to duplicate the Pad A OTV system except for minor physical site differences.

b. Definition of System

The LC-39 OTV system provides visual observation of prelaunch and launch activities as seen by strategically located television cameras at pad A, pad B, the Orbiter processing facility, the Vehicle Assembly Building, and on the mobile launchers. These television cameras are equipped with pan-and-tilt units and with variable focal length zoom lenses (16mm to 320mm) that are remotely controlled via a digital control system from the LCC. The video signals are transmitted to the LCC over air dielectric coaxial cable with 10 television channels frequency-modulated (FM) and band-stacked (frequency division multiplexed) on each coaxial cable. At the LCC, these FM carriers (90 channels per pad) are demodulated and routed to a 192 x 512 video routing switcher for distribution to firing rooms and other user monitors. Selected television cameras are routed to a recording facility where 25 recorders/players record and play back in accordance with user needs. The OTV system consists of the following system/subsystems:

(1) Cameras

(2) Pan-and-tilt units

(3) Cabling system

(4) FM transmission system

(5) Switching system

(6) Monitoring system

(7) Digital control system

(8) Record system

c. Capabilities

The combined OTV subsystems provide the following capabilities:

(1) Black-and- White TV Cameras
Resolution:	750 TV lines
Sensitivity:	Full output with scene illuminations from 20 foot-candles to full sunlight.
Standard:	RS170 525-line interlaced scanning
.
(2) Modulators/Demodulators (RF system)
Modulation:	Frequency modulation
Bandwidth:	6 MHz (450 lines TV resolution)
.
(3) Video Distribution
Bandwidth:	10 MHz (750 lines TV resolution)
.
(4) User Monitors
Resolution:	600 TV lines
.
(5) Color TV Cameras
Resolution:	300 TV lines
Sensitivity:	Full output with scene illuminations from 20 foot-candles to full sunlight.
Standard:	American "NTSC"
.
(6) Recorders
Resolution:	260 TV lines
Standard:	3/4-in. U-Matic

These OTV subsystems combined into a "system" providing TV coverage with a maximum of 450-TV-line resolution for pad black-and-white cameras and 280-TV-line resorption for Public Affairs Office (PAO) broadcast color TV cameras. This resolution is sufficient for broadcast and for day-to-day operational viewing; however, it falls far short of that required for detailed analysis in the event of a problem.

OTV camera placements are shown in figures 8 through 12. TV systems are also located in the Vehicle Assembly Building and in the Orbiter processing facility. Views are documented in OTV document KSCL-3420-021, Rev. 0, dated April 24, 1985.

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[N13]

Figure 6. Location of Cameras on MLP-2 (51-L Configuration).

Figure 7. Tracking Camera Locations.

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[N14]

Figure 7 [Table 7?]. Viewing Angles and Coordinates of FSS and MLP-2 Cameras.

Figure 8. LC-39 MLP, FSS, and RSS Camera Locations.

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[N15]

Figure 9. LC-39 Camera Locations.

Figure 10. FSS Camera Locations.

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[N16]

Figure 11. Rotary Service Structure Camera Locations.

Figure 12. MLP Camera Locations.

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[N17]

Figure 13. Image Processing.

Figure 14. Visual Analysis Subteam (VAST) Image Analysis System.

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[N18] 4. Enhancement Systems

In addition to the usual viewing equipment such as light tables and projectors, digital image processing systems were employed on selected image frames by JSC, MSFC, and several government and industry organizations. Such systems provide image digitization, image data management, image mensuration, integrated computer-aided-design (CAD) and image processing of various types, and image display including color photography and animation on video tape. Each selected frame was appropriately processed to enhance or measure features of interest, with specific analysis techniques selected from general capabilities such as are indicated in figure 13. An overview of the JSC and MSFC digital image processing system hardware and software is given. The other government and industry organizations employed in enhancement and analysis also are listed in Section V.D.8.

The JSC digital image processing system is represented by the diagram in figure 14. An Eikonix model 850 linear array film digitizer with color and black-and-white capabilities was used. A Gould IP 8500 color image display and real-time disk allows evaluation of image quality, provides image data management, and supports image analysis through two image terminals accessing a modified Library of Image Processing Subroutines (LIPS). This system also provides video digitizing. A DEC Microvax II processor is the host computer system. Disk space of 786 megabytes and 9 megabytes of memory are available as well as a DECNET network interface. CAD manipulation capability allows measurement of size, location, shape, relative motion, and other features. Three engineering CAD systems were employed at JSC to generate automatically views of the stack from the camera's viewpoint. The JSC image processing system has both video and photo outputs.

MSFC used two networked image processing systems in parallel for image file transfer. Figures 15 and 16 show block diagrams of the two systems (subsequently referred to as IP1 and IP2). Both interface with the International Imaging Systems (IIS) model 600 hardware/software package for interactive image analysis and display. Both systems also have identical video input/output systems for processing and recording digital imagery on video tape and making a photographic hardcopy.

IP1 at MSFC is supported by a VAX 11/730 central Processing unit and serves as the primary system for image digitization and display. An Optronics model 4500 is the primary tool used to digitize film products, but an Eikonix CCD film digitizer is sometimes used for quick-look analyses. In addition, a Perkin Elmer microdensitometer is used to digitize selected frames at higher spatial resolution. Color and black-and-white capabilities exist on all three digitizers. IP2 is supported by a VAX 11/785 central processing unit and serves as the primary system for integrating image processing functions with CAD/CAM engineering files. IP2 supports concurrently the Intergraph Engineering Design Station (with image display capability) and the IIS model 600 image processing system. Disk space of 1.2 gigabytes and 16 megabytes of memory are used to support file management of image and design data and to provide sufficient central processing speed for numerical calculations.

V. C. INTEGRATED TIMELINE.

1. Introduction

The events listed in the timeline (figure 17) are derived from two major independent data sources: telemetry and photography. The significant ascent events start with Solid Rocket Booster ignition and end with SRB destruct. A common vehicle coordinate system used for both photographic and telemetry events is shown in figure 18. Event times listed in this report are given in mission elapsed time, with SRB ignition defined at 028:16:38:00.010 Greenwich mean time (GMT).

a. Telemetry Events

The telemetry events include some key expected ascent occurrences such as Space Shuttle main engine (SSME) throttle commands to 104 percent, 94 percent, etc. These are listed for reference purposes only and in no way represent deviations from the normal. They are marked by an asterisk (*) in the timeline.

Data from two telemetry systems were used to identify telemetry events. The systems can be differentiated by the event measurement numbers "V", "T", and "B" series numbers (example V41P1300C) for the Orbiter, and "E" series numbers (example E41M3076D) for the SSME's. A description of each measurement or telemetry event and its sample rate, if applicable, is included.

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[N19]

Figure 16. MSFC Image Processing System Two (IP2) (Integrated Image Analysis- CAD/CAM System).

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Time applied to Orbiter telemetry data is derived from the onboard Orbiter master timing unit (MTU) time which is synchronized with GMT prior to launch. The onboard MTU time is included in the Orbiter downlinked telemetry bit stream and is downlinked at 10 samples/second with the data. The event times are adjusted for all known delays within the Orbiter telemetry to within the tolerance indicated on the timeline. The tolerance listed with each time indicates that the event occurred as first observed by this sample, but due to the nature of sampled data, may have actually occurred within one preceding sample period.

Unlike the Orbiter, the onboard MTU time is not telemetered with the engine data. Instead, a counter for each engine resets after the engine start command is validated by each engine controller. The GMT of the individual engine start commands is then used to time tag the engine data frames. The time uncertainty listed with each engine event includes the uncertainty associated with the engine counter reset as seen in the telemetered data as well as the sample rate of the measurement. Sequential events for engine performance measurements are known to a much greater accuracy.

All times are listed in both GMT and MET which is referenced to T-0 as identified by the SRB ignition command.

The raw data source for all the telemetry vents is either the Space Shuttle main engine 60-kilobit (kb) data from each engine or the Orbiter downlinked 192-kb bitstream (128-kb data + 64-kb voice) as recorded at the Merritt Island Launch Area (MILA) ground station. Data tapes recorded at both MILA and Ponce de Leon (PDL), the official range sites, have been examined on a telemetry frame-by-frame basis to extract the last usable data.

b. Photographic Events

Photographic events are identified by MET and the camera number. The time listed in the timeline for each photographic event is the time of the center of each film frame and the tolerance is derived from the camera frame rate. All launch film was reviewed, and the camera identified for each event is the camera on which the event first appears. Timing notes, time, and film speed are as follows:

(1) Cameras 202, 204, 206, 207, and 216: Timing is marked on the film and is film-frame referenced. Therefore, the onset of the observed event is considered to have occurred between the first frame in which it is seen and the preceding frame ( + 0 frame, - 1 frame).

(2) Camera 230: Time is recorded on every other frame. The onset of the observed event is considered to have occurred between the frame in which it is first seen and the previous frame.

(3) Camera 203: Film does not have a time frame reference recorded and therefore results in an uncertainty of plus or minus one-half frame. The onset of the observed event is considered to have occurred between the frame in which it is first seen and the preceding frame ( + 0 frame, -1 frame), for a total inaccuracy of + 1/2 frame, -1 1/2 frames.

[N20] (4) Cameras E8, E9, E60 and E63: Film does not have a time frame reference recorded and therefore results in an uncertainty of plus or minus one frame. The onset of the observed event is considered to have occurred between the first frame in which it was seen and the preceding frame ( + O frame, - 1 frame), for a total inaccuracy of + 1 frame, - 2 frames.

(5) Camera CZR-1: Camera CZR-1 time is marked on the film. Therefore, the onset of the observed event is considered to have occurred between the first frame in which it is seen and the preceding frame ( + O frame, - 1 frame).

(6) Camera D67: Film is not time-coded, and film frame rate is variable between 4 to 5.5 frames/second. The camera also skews its look angle upward after lift-off. Time estimates have been made utilizing the launch tower as a reference for measuring T-O.

(7) Film Speed and Accuracy: The film speed and accuracy are shown in the following table:

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[N20-N23]

Figure 17. Incident Integrated Timeline.

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[N23]

Figure 18. Vehicle Coordinate System

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[N24]

Figure 19. Camera Locations and Look Angles.

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[N25] The location of the cameras and their look angles is specified in figure 19.

2. Events

Each event listed in figure 17 is shown with the data and/or photography which describes the event. The event numbers correspond to the numbers shown in figure 17.

(1) Calculation of SSME and SRB Ignition Times

Mission elapsed time: T-0

The SSME and SRB ignition signals are a result of software flags which are generated in the redundant set launch sequencer (RSLS). For the SSME's, the flag is interpreted by the SSME software operation program (SOP) and sent to the engine interface unit (EIU). For the SRB's, the flag is interpreted by the master events controller (MEC) SOP and sent to the SRB ignition pyrotechnics. All of the times are referenced from an expected time of lift-off (GMTLO, V99W8801C) that was sent from the launch processing system to the RSLS. The RSLS subtracts the GMTLO value from its current value for GMT; this difference is the high-frequency executive read of GMT completed 54 milliseconds prior to the start of the 40-millisecond cycle in which the RSLS is running and checks to see if the difference is less than 6.600 seconds. On the first pass that the criteria is satisfied, the software flag for main engine 3 start command is set. The calculation of this difference is not made again, and the last value is held in the telemetry stream (V90W8380C). The timing is such that 6.600 seconds after this time, the software flag is set by the RSLS for the MEC SOP to fire the SRB ignition pyrotechnics.

Forty milliseconds after setting the software flag for SRB ignition, the RSLS logic sets a flag for T-0 umbilical-release fire commands. The MEC SOP translates this into a command to the MEC for T-0 umbilical release. The MEC splits this input into T-0 umbilical release and holddown-bolt pyrotechnics fire commands which leave the MEC 40 milliseconds after the SRB ignition pyrotechnic fire commands had left. Following the 40-millisecond cycle, the RSLS sets a flag to reset the MEC and then terminates operation.

(2) Holddown Post 2 PIC Firing - Smoke Puff from Dome of Frangible Nut on Holddown Post

Mission elapsed time: 00.008

Source: Camera E8

The E8 camera is stationary and is located on the mobile launch platform. It views the right SRB aft skirt and holddown posts from prior to ignition until after launch. At 00.008 second MET, the pyrotechnic initiator capacitor (PIC) firing is indicated by a small smoke puff from the dome of the frangible nut. On the top photo (figure 20), the first indication of this smoke is difficult to see without a frame-by-frame analysis. Also, the shadow obscures the smoke. The bottom photo is taken approximately 0.040....

[N26] ....second later, and shows that the smoke is clearly visible although somewhat obscured by the shadow cast on the holddown post.

(3) First Continuous Vertical Motion

Mission elapsed time: 00.250 Source: Camera E9

Figure 21 shows the first continuous vertical motion of the vehicle as the booster lifts from the pad and the luminous exhaust plume from the Solid Rocket Booster becomes prominent.

(4) Confirmed Smoke Above Field Splice Initially Moves in + X Direction

Immediately after solid rocket motor (SRM) ignition, dark smoke is observed billowing out from between the right SRB and the external tank. The exact location of the smoke source is not viewed directly. Visual analysis and image enhancement of film from five camera locations have been used to determine the approximate origin of the smoke in space and time, to characterize the dynamic behavior of the smoke, and to determine its longevity.

Mission elapsed time: 00.678

Source: Camera E60

The consensus opinion of the film interpreters is that smoke is first discernible at 00.678 second MET from camera E60. It becomes visible on other cameras shortly thereafter; figure 22 presents views from two cameras showing the first evidence of the smoke. Based on these and other cameras, the smoke appears to be dark in color (brownish-gray under strong illumination and....

The time relationship of the general-purpose computer (GPC) outputs to the EIU and master events controller to the run time for the softwater modules (RSLS, SSME, SOP, and MEC SOP) in the GPC 40-millisecond cycle are shown in the following:

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[N27] ....nearly black when shadowed) and is first seen above the aft to aft-center segment field splice as shown on the computer-aided design drawing of figure 23. The smoke appears to move upward in the + X direction in the next few frames after it first appears.

Figure 24 presents the viewing angles of all of the cameras which observed the smoke, and figures 25 through 27 provide examples of the views from several of these cameras. The crosshatched area of the CAD drawing in figure 28 shows the region of the smoke origin determined to be between 270 degrees and 310 degrees clockwise from the + Z axis toward the ET.

(5) Multiple Puffs of Smoke

Mission elapsed time: 00.836 to 02.499

Source: Camera E63

During the first few seconds after lift-off, the smoke appears to exhibit multiple puff characteristics. After an initial upward movement of a particular mass of smoke, the motion of the vehicle causes that mass to trail off rearward relative to the vehicle. A new puff of smoke is evidenced when another mass of smoke with relative upward movement compared to the previous puff is seen.

Figures 29 through 31 present photographs of the smoke during this time. Figures 32 through 34 show motion analyzer plots (graphic depictions of the events as measured from the film) of the smoke cloud behavior from 02.064 seconds MET to 02.266 seconds MET. Figures 32 and 33 show the rearward motion relative to the vehicle of a particular puff of smoke. Figure 34 shows the development of a new puff in relation to the earlier one. Figure 35 shows the relative motion of the top of the smoke in relation to a fixed reference. Smoke motions indicative of separate puffs are marked on the figure and have been identified beginning at the following times:

00.836 seconds MET

01.171 seconds MET

01.283 seconds MET

01.496 seconds MET

01.779 seconds MET

02.185 seconds MET

02.296 seconds MET

02.499 seconds MET

Since the point of origin of the smoke is not visible to the cameras, it is not certain that these separate puff motions are due to a pulsating source of smoke. Harmonic vehicle motions resulting from the lift-off ~twang" could possibly account for some of the observed motion.

 

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Figure 22. Camera CZR-1 at 02.733 MET (left) and Camera E60 at 02.738 MET (right).

Figure 23. Wire-Frame CAD Drawing of Launch White Smoke Location Indicated.

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[N28]

Figure 24. Cameras Which Observed Smoke.

Figure 25. Camera D67 at 01.600 MET.

Figure 26. Camera E60 at 01.606 MET.

Figure 27. Camera E63 at 01.648 MET.

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[N29]

Figure 28. CAD Plan View with Launch Camera Views.

Figure 29. Camera E63 at 01.648 MET (left) and Camera E63 at 01.750 MET (right).

Figure 30. Camera E63 at 01.648 MET (left) and Camera E63 at 01.750 MET (right).

Figure 31. Camera E63 at 02.259 MET (left) and Camera D67 (exact time unknown) (right).

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[N30]

Figure 32. Smoke Puff Definition at 02.064 MET.

Figure 33. Smoke Puff Definition at 02.164 MET.

Figure 34. Smoke Puff Definition at 02.266 MET.

Figure 35. Motion of Top of Smoke Puff.

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[N31]

Figure 36. Camera CZR-1 at 02.733 MET (left) and Camera E60 at 02.738 MET (right).

Figure 37. Camera E60 at 03.375 MET (left) and Camera E217 (exact time unknown) (right).

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(6) Last Positive Evidence of Smoke Above Right Aft SRB/ET Attach Ring

Mission elapsed time: 02.733

Source: Cameras CZR-I and E60

The CZR-I camera was used to determine the last positive evidence of smoke above the right aft SRB/ET attachment ring because the detail in the picture allows accurate identification of the SRB structure. The E60 camera photograph from a similar viewing angle and time offers corroborating evidence. Both photographs are shown in figure 36.

(7) Last Positive Visual Indication of Smoke Dispersing Below ET Aft Dome

Mission elapsed time: 03.375

Source: Cameras E60 and E217

With increasing upward velocity of the vehicle, the smoke is dispersed below the vehicle. The last positive visual indication of the smoke as it disperses below the ET aft dome is seen on camera E60 at 03.375 seconds MET. Figure 37 shows this event along with a view from camera E217 at approximately the same time. The smoke is difficult to distinguish from the plume gases and can be tracked only by performing frame-to-frame visual analysis. After this time in flight, the vehicle motion, the ET aft dome insulation outgassing, and the vehicle plumes combine to make observation of smoke difficult, if not impossible. No definite evidence of smoke can be confirmed at any time after 03.375 seconds MET.

(8) SSME Throttle Commands-104 Percent

The main engine 1 and 2 vehicle commands occurred prior to the main engine 3 command. Therefore, the times selected for the completion of the command throttle events were defined by using E41M3076D (ME-3 vehicle command). ME-3 vehicle command E41M3076D is a 25-sample/second measurement located in the 60-kilobit MSFC data stream with an established tolerance of + 0.045, - 0.035 second (see figure 38). These are normal ascent events to be used for reference only. The times selected are as follows:

 

104 percent - 04.364 seconds MET

94 percent - 19.885 seconds MET

65 percent - 35.406 seconds MET

104 percent - 51.886 seconds MET

(9) Vehicle Roll Program Initiate

The vehicle roll program initiate data were taken from V9OR5301C [selected rate gyro accelerometer (RGA) roll rate]. This measurement has a 5-sample/second sample rate which corresponds to a + 000, - 0.20 time tolerance. The time selected was 07.724 seconds MET (see figure 39). This is a normal ascent event to be used for reference only.

(10) SSME 94 Percent Command

This command is shown on figure 38.

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[N32]

Figure 38. SSME Engine Throttle Commands.

Figure 39. Vehicle Roll Program Initiate.

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(11) Vehicle Roll Program Complete

The vehicle roll program complete data were taken from V9OR5301C (selected RGA roll rate). This measurement has a 5-sample/second sample rate which corresponds to a + 000, - O.20 time tolerance. The selected time was 21.124 seconds MET (see figure 40). This is a normal ascent event to be used for reference only.

(12) Start Right SRB Maximum Dynamic Pressure Bucket

The start of the SRB maximum dynamic pressure bucket was defined using measurement B47P1302C for the left SRB chamber pressure and B47P2302C for the right SRB chamber pressure (see figure 41). The measurements used have a 12.5-sample/second sample rate which corresponds to an accuracy tolerance of 0.080 second. The time of the event is 21.604 seconds MET which is the first data sample after the slope change.

Right SRB - 21.604 second

(13) Start Left SRB Maximum Dynamic Pressure Buck

The start of the left SRB maximum dynamic pressure is 22.204 seconds MET and was derived as in event (12).

(14) SSME 65 Percent Command

This command is shown on figure 38.

(15) Interval of Roll and Yaw Attitude Error "Response to Wind"

During the interval from 36.990 to 62.990 seconds MET, the roll and yaw attitude errors that were observed have been identified as responses to ascent winds (see figure 42). The measurements selected to bound this interval are body yaw attitude error (V95H3522C) and body roll attitude error (V95H3523C).

(16) SSME 104 Percent Command

The command is shown on figure 38.

(17) End Left SRB Maximum Dynamic Pressure Bucket

The end of the SRB maximum dynamic pressure bucket was defined using measurement B47P1302C for the left SRB chamber pressure and B47P2302C for the right SRB chamber pressure. The measurements used have a 12.5-sample/second sample rate which corresponds to an accuracy tolerance of 0.080 second. The time of the event was established by selecting the first data sample from both measurements reflecting a chamber pressure increase after the minimum SRB chamber pressure maximum dynamic pressure bucket (see figure 43). The selected times for the events are:

 

Left SRB-54.124 seconds MET

Right SRB-54.324 seconds MET

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[N33]

Figure 40. Vehicle Roll Program Complete.

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[N34]

Figure 41. SRB Throttle Bucket.

Figure 42. Interval of Roll and Yaw Attitude Error Response to Wind.

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(18) End Right SRB Maximum Dynamic Pressure Bucket

See (17).

(19) First Evidence of Flame on Right SRB (enhanced)

The flame from the right SRB was first seen between the right SRB and the ET at 58.762 seconds MET on camera E207 using imagery enhancement. The flame is observed to flicker and then grow into a continuous, well-defined plume at 59.262 seconds MET.

 

Mission elapsed time: 58.762

Source: Camera E207

Photography from cameras E203, E207, and E216 was used to identify the location of the first flame. The flame origin was estimated to be 315 degrees ( + 10 deg) clockwise from the + Z axis of the SRB towards the ET and near the aft field joint. This estimate was produced by the use of an image analysis system. Figure 44 with a CAD overlay shows the earliest detection of the flame on E207 at 58.762 seconds MET.

(19) First Evidence of Flame on Right SRB

Mission elapsed time: 58.788

Source: Camera E207

Figure 45 shows the first evidence of flame on the right SRB. This is only one frame later than the enhancements could detect.

(20) Flickering Dynamic Plume on Right SRB

Mission elapsed time: 58.762 to 59.262

Source: Camera E207

Figure 46 shows the visual evidence of flickering. The top photo shows the flame at 59.087 seconds MET while the flame is not apparent in the bottom photo taken at 59.112 seconds MET.

Image enhancements by various organizations detected the leak at 58.762 seconds. Verification that flickering was seen directly (not as a reflection) was confirmed by the fact that brightness levels remained constant in other presumed reflection areas. The flickering was characterized by maximum, average, and minimum intensities versus time, and by frequency analysis.

Figure 47 is a composite of a sequence of 40 frames from camera E207 (printed with Orbiter oriented at top of stack) and shows the growth of the plume from 58.762 seconds MET through 59.661 seconds MET. The white boxes outline the location of the plume. The intermittent nature of the plume is observed. Fluctuations in intensity can be seen between 58.788 seconds MET and 59.262 seconds MET. At 59.262 seconds MET, the plume becomes well established and continues to grow, although some variation in intensity is still evident.

Figure 48 depicts the flame without any background data or reflections. This was accomplished by electronically subtracting the image with no flame visible (frame 20 of figure 48) from frames 21 to 59. The maximum brightness level of these resultant images is plotted in figure 49. Figure 50 shows a power density spectrum....

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[N35]

Figure 43. SRB Maximum Dynamic Pressure Bucket and Chamber Pressure Divergence.

Figure 44. Camera E207 at 58.762 MET With CAD Inlay.

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...of the maximum intensity of the flame from the right SRB. The dominant frequency of the flickering is every fourth frame which corresponds to a pulse rate of 10/sec.

(21) Reconstructed Maximum Dynamic Pressure (720 psf)

The maximum dynamic pressure in pounds per square foot (psf) was derived using the lift-off + 10 minutes rawinsonde wind data and the best estimate of trajectory (BET) (see figure 51). The maximum value of 720 psf occurred at 59.000 seconds MET.

(22) Continuous Well-Defined Plume on the Right SRB in + Z. - Y Coordinates

Mission elapsed time: 59.262

Source: Camera E207

The flame became a continuous well-defined plume at 59.262 seconds MET, although it continued to vary in intensity as shown in figure 52. The CAD drawing gives the approximate location of the flame source.

Several image analysis techniques were employed to ascertain the origin of the plume on the right SRB. Figure 53 shows a frame from camera E207 at 59.487 seconds MET with CAD overlay. Figure 54 shows a frame from camera E-216 at 59.507 seconds MET registered with the appropriate CAD drawing. The flame origin was estimated to be at 45 degrees ( + or - 10 degrees) from the + Z axis of the right SRB toward the ET and near the aft field joint.

(23) Visual Evidence of Flame from Right SRB in + Z Direction Near ET Attach Ring

Mission elapsed time: 59.753

Source: Camera E204

The first evidence of flame as shown in figure 55 is seen from the south at Melbourne Beach at 59.753 seconds MET, almost a second later than it can be seen from the north. This view is slightly out of focus because the camera was focused for the nominal SRB separation distance.

(24) SRB Chamber Pressure Divergence (Right Hand Versus Left Hand)

The start of the SRB chamber pressure divergence (right versus left) was defined using measurement B47P1302C for the left SRB chamber pressure and B47P2302C for the right SRB chamber pressure. The measurements used have a 12.5-sample/second sample rate which corresponds to an accuracy tolerance of 0.080 second. The time of the event was established using measurement B47P2302C at the second data sample of the flat chamber pressure (see figure 43). The established event time for the right SRB is 60.004 seconds MET.

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[N36]

Figure 45. Camera E207 at 57.788 MET (above) and Hidden-Line CAD Drawing with Plume location indicated (right).

Figure 46. Camera E207 at 59.087 MET (top) and 59.112 MET (Bottom) and Hidden-Line CAD Drawing with Plume location indicated (right).

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(25) First Evidence of Plume Deflection Intermittent

Mission elapsed time: 60.238

Source: Camera E207

As the plume from the side of the right SRB increased in size, it was impinging on the external tank and deflected by aerodynamic forces. The plume deflection was intermittent. The first evidence of the plume deflection through visual analysis is at 60.238 seconds MET and is best seen first from camera E207 (see figure 56). A second photograph from camera E207 taken 0.223 second later shows the deflection of the plume more clearly. (See figure 57).

(26) First Evidence of Anomalous SRB Plume Attaching to theme

Mission elapsed time: 60.248

Source: Camera E203

Figure 58 shows a view of the vehicle from almost directly aft with only parts of the SRB's and ET visible. The vehicle is difficult to identify because the film is exposed for plume characteristics. However, the anomalous plume is very prominent. Visual analysis shows that the growing plume arcs around some 60° of the external tank structure at the 2058 ring frame. The location was verified by using an image analysis system to overlay CAD drawings on the images. The first frame on which this event can be identified is from camera E203 at 60.248 seconds MET, but the event is better depicted from the same camera at 60.614 seconds MET.

(27) First Evidence of Plume Deflection-Continuous

Mission elapsed time: 60.988

Source: Camera E207

Continuous deflection of the plume is first apparent on camera E207 at 60.988 seconds MET as shown in figure 59. From this time, the plume grows rapidly, eventually obscuring the lower section of the ET, as depicted on the annotated CAD drawing.

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[N37]

Figure 47. Camera E207 Composite.

Figure 48. Flame Seen From Camera E207 Frames 20 to 59 With All Background Data Electronically Deleted.

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[N38]

Figure 49. Maximum Brightness Level of the Flame Seen from Camera E207 Frames 20 to 59.

Figure 50. Power Spectrum of Flame Intensity.

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[N39]

Figure 51. Reconstructed Dymanic Pressure.

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[N40]

Figure 52. Camera E207 at 59.262 MET (above) and Wire-Frame CAD Drawing (Right).

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[N41]

Figure 53. Camera E207 at 59.487 MET with CAD Inlay.

Figure 54. Camera E216 at 59.507 MET with CAD Inlay.

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[N42]

Figure 55. Camera E204 and 59.753 MET (above) and CAD Drawing (right). Photograph taken at 60.586 MET.

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[N43]

Figure 56. Camera E207 at 60.238 MET.

Figure 57. Camera E207 at 60.461 MET.

Figure 58. Camera E207 at 60.614 MET.

Figure 59. Camera E207 at 60.988 MET (above) and Annotated CAD Drawing (right).

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[N44] (28) Start of Left SRB Thrust Vector Control Rock Actuator Spike

The start of the left SRB thrust vector control actuator spike was taken from measurement B58H1150C (see figure 60). This measurement has a sample rate of 25 samples/second which results in a time tolerance of 0.040 second. The event time selected, 62.094 seconds MET, is the data point defining the maximum rock actuator negative position prior to loss of data.

(29) Right-Hand Outboard Elevon Actuator Hinge Moment Spike

The right-hand outboard actuator hinge moment spike was defined using the right outboard elevon primary differential pressure I measurement (V58P0966C). The first data point depicting the peak of the actuator hinge moment spike was selected. The measurement has a 12.5-sample/second sample rate with an accuracy tolerance of 0.080 second. The selected time of the right-hand outboard actuator hinge moment spike peak was 62.484 seconds MET (see figure 61).

(30) Right-Hand Outboard Actuator Differential Pressure Change

The right-hand outboard elevon actuator differential pressure change was defined using measurement V58P0966C, which is the right outboard elevon primary differential pressure 1. The first data point indicating the unexpected change in right-hand elevon differential pressure was selected. The measurement has a 12.5-sample/second sample rate with an accuracy tolerance of 0.080 second. The time of the right-hand outboard elevon actuator differential pressure change was 63.924 seconds MET (see figure 61).

(31) Start Vehicle Pitch-Rate Change

The start of the vehicle pitch-rate change was defined using measurement V9OR2525C, which is the left SRB pitch rate. The first data point which reflects the start of the vehicle pitch-rate change was selected to establish the time of the event. The pitchrate change measurement has a 5-sample/second sample rate with an accuracy tolerance of 0.2 second. The start time of the vehicle pitch-rate change was 64.604 seconds MET (see figure 62).

(32) Abrupt Change in Anomalous Plume Shape; First Indication of Liquid Hydrogen Leak Near ET 2058 Ring Frame

Mission elapsed time: 64.660

Source: Camera E204

An abrupt change in the shape of the anomalous plume occurs at 64.660 seconds MET and is the first indication of a hydrogen leak. This change is shown in figure 63. This leak is corroborated by changes in the