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VOLUME 1 |
THIS VOLUME- REPORT SUMMARIES
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VOLUME 2 |
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Chart |
Title |
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1. |
STS 51-L Data & Design Analysis Task Force. |
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2. |
Search, Recovery and Reconstruction Team. |
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Figure |
Title |
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0. |
Shuttle Coordinate Systems and Dimensions. |
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0-1. |
Orbiter Vehicle Dimensions. |
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1. |
Right SRB and FAA Radar Impacts. |
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2. |
Impacts From Radar Data. |
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3. |
Current Search Area. |
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4. |
Orbiter and Reference Axes. |
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5. |
External Tank & Reference Axes. |
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6. |
SRB Coordinate System Looking Aft. |
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7. |
Physical Evidence vs 51-L Fault Tree. |
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8. |
Physical Evidence vs 51-L Fault Tree. |
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9. |
Physical Evidence vs 51-L Fault Tree. |
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Photograph |
Title |
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1. |
Layout of Orbiter Debris. |
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2. |
Layout of External Tank Debris. |
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3. |
SRB Fracture Surface. |
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4. |
SSME as Recovered. |
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5. |
Undetonated Linear Shape Charge. |
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6. |
Undetonated Linear Shape Charge. |
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7. |
Unburned or Unscorched Debris from Payload Bay. |
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8. |
Bent IUS Beam. |
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9. |
Aft Center Segment with Burn Thru Hole Contact #131. |
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10. |
Aft Center Segment with Burn Thru Hole Contact #131. |
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11. |
Mockup of Hole on Right-Hand SRB Aft Field Joint. |
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Table |
Title |
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1. |
Search and Salvage Vessel Assets and Capabilities. |
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2. |
Summary of Underwater STS 51-L Contacts Recovered. |
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3. |
Orbiter Components Returned for Analysis. |
At 11:38:00.010 Eastern Standard Time (EST) on January 28 1986, Mission 51-L Shuttle was launched from Launch Complex (LC) 39B at the John F. Kennedy Space Center, Florida, with seven astronauts aboard. As observed and recorded on video tape at 74.130 seconds after liftoff, the Shuttle was engulfed in flames. It began a catastrophic breakup. Both Solid Rocket Boosters (SRB's) separated from the External Tank (ET) and continued powered flight on erratic courses until the Range Command Destruct signal was sent by the Range Safety Officer (RSO) at 11:39:50.2. Numerous large pieces of the Orbiter, "Challenger," and the ET were observed to descend from the point of initial breakup and fall into the Atlantic Ocean east-northeast of the Kennedy Space Center (KSC). After Command Destruct action, the SRB's started to break into many pieces and fall into the ocean east of the Orbiter and ET impact area.
The Air Force Eastern Space and Missile Center (ESMC) was tasked by the Program Requirement Document (PRD) to provide both radar and optical tracking for Mission 51-L launch. This tasking is provided for all Space Transportation System (STS) launches in order to provide data for the performance of the Range Safety function and also to provide engineering and trajectory data to the National Aeronautics and Space Administration (NASA). The status of these systems was briefed at the Commander's Mission Briefing (see DDATF Pre-Launch Activities Team Report, Appendix J, Appendix 6) and the NASA Launch Readiness Review on January 14, 1986 (see Appendix F). The radar and optical data was used by the RSO to verify the vehicle had experienced a catastrophic breakup and both SRB's were still propulsive following the initial breakup at T+ 74 seconds. This data also provides the basis for water impact predictions used in the initial stages of surface recovery. The lack of a multi-object tracking system made the prediction of radar and optical data extremely difficult and, to a large measure, accounted for the lengthy search and recovery operations.
The Department of Defense Manager's STS Contingency Support Operations Center initiated a search and rescue operation on behalf of NASA. The surface search was directed by the Launch Recovery Director (LRD), in accordance with the STS Contingency Support Operations Plan dated 1 December 1985 (see Appendix G), and the Department of Defense Manager for Space Shuttle Contingency Support (DDMS). The surface search was coordinated by the United States Coast Guard (USCG) with assistance from ESMC. The surface search was terminated on February 7, 1986. The Department of the Navy was also requested to initiate preparation for an underwater salvage operation.
NASA established three areas for storage and reconstruction. The Logistics Building and an adjacent area on KSC were used for Orbiter and ET debris, respectively, and on Cape Canaveral Air Force Station (CCAFS), Hangar "O" and the EOD Range were used for SRB debris.
On January 28, 1986, Dr. William Graham, NASA Acting Administrator, appointed Mr. Jesse Moore to act as the interim 51-L Mishap Investigation Board chairman. Mr. Moore requested that Col. Edward O'Connor direct the activity of the NASA LRD and coordinate the development of the necessary search and recovery organizations required to support the recovery of the 51-L flight crew and those flight components that would provide the basis for the accident investigation. Col. O'Connor also directed the development of the recovered components preservation plan and requested Mr. Terry Armentrout of the National Transportation Safety Board (NTSB) to establish a Structural Reconstruction and Evaluation Group composed of engineering representatives from the STS element contractors, NASA, and the NTSB. Col. O'Connor provided continuing direction to these activities until formally chartered as Team Lead for the Search, Recovery, and Reconstruction Team of the Task Force on March 20, 1986.
Initial priorities for the underwater salvage operations were as follows:
- 1. Right-Hand Solid Rocket Booster (SRB)
- 2. Left-Hand SRB
- 3. Orbiter Crew Compartment
- 4. Payload
The recovery of Mission 51-L Shuttle components for support of the accident investigation activities of the Task Force was terminated on May 1, 1986. The deep water SRB recovery was terminated after the recovery of Contacts #131 and #712 which contain approximately 90% of the burn-through area of the right-hand aft field joint. This is believed to be the origin of the initial failure. Shallow water recovery was deemed to have provided sufficient material to confirm that the right-hand SRB failure was the initiating failure mode and that all other flight components failed subsequent to this failure.
Some shallow water recovery will continue in order to provide material for NASA Design Centers' Material Properties Studies.
The following pages provide a narrative of the activities leading to the recovery of debris as well as the structural reconfiguration and evaluation. The detailed source data for this report are in Enclosures 1 through 9.
Remarks:
This report utilizes the manufacturer's coordinate system. This system was selected because the reconstruction process required use of the manufacturer's drawings. Reference Figures 0 and 0-1 for the axes and coordinates.
The Photo and TV Support Team utilized the Flight Dynamics coordinate system which is illustrated in Volume 1 of their report.
III. Organizational Structure Technique.
The following two charts show the top levels of the organization as charted by Rear Admiral Richard Truly and does not represent the multitude of people that participated in the Search, Recovery, and Reconstruction Task.
Immediately following the mishap, the NASA LRD requested that the NASA SRB retrieval vessels proceed to the water impact location and also requested that DDMS dispatch all immediately available surface vessels and aircraft to the area of the mishap. The ESMC RSO held all aircraft and surface vessels outside of the falling debris area until entry was deemed to be safe from falling materials that could cause a hazard to the crews entering the area. Approximately one hour after the mishap, a surface search was initiated in the immediate area surrounding the water impact location of the Orbiter and ET. A large amount of Orbiter and ET debris was found floating and was recovered by surface ships. Due to the currents of the Gulf Stream, the surface search was expanded to the north and, over the next several days, extended to an area 450 nautical miles north of the initial search area.
Radar tracking data from the ESMC was utilized to determine the area for the underwater search and sonar mapping of this area commenced. The search area was subsequently expanded based on further data reduction efforts that identified a wider dispersion of Right SRB components following the Command Destruct.
Identification of individual sonar contacts was accomplished by remotely-operated vehicles (ROV's) and manned submersibles in both shallow water and deep water areas as well as divers in shallow (less than 200 ft. (61 meters)) water. This identification established the debris to be recovered as well as the priorities of recovery. Plans were developed for the recovery technique, safing, and preservation of the components.
II. Directive Appointing Team/Charter.
[O5] Figure 0. Shuttle Coordinate Systems and Dimensions.
[06] Figure 0-1. Orbiter Vehicle Dimensions.
[O7-O8] Letter. [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]
[O9] 51-L DATA AND DESIGN ANALYSIS TASK FORCE [To: E. O'Connor; From: Task Force Chairman; Subject: Appointment of Lead; Search, Recovery and Reconstruction Team]
[O10] GENERAL ASSIGNMENT FOR SEARCH, RECOVERY AND RECONSTRUCTION TEAM.
[O11] CHART 1. STS 51-L DATA & DESIGN ANALYSIS TASK FORCE. CHART 2. SEARCH RECOVERY AND RECONSTRUCTION TEAM.
[O12] The recovery was accomplished by the divers and submersibles. The recovered parts were delivered to impound areas for possible reconstruction.
The Orbiter, ET, SRB's, and cargo (payloads) were placed in separate areas for reconstruction. The reconstruction placed the components in as close a proximity to the original configuration as possible. The debris was photographed and examined for physical evidence and samples were then taken for laboratory examination.
The analyses of the recovered components conducted by the National Transportation Safety Board (NTSB) were used to verify the conclusions of the Accident Analysis Team in determining the specific failure modes/scenarios dispositions (probable, improbable, and possible).
At the time of writing this report, the identification, recovery and reconstruction tasks are still in progress.
IV. Definition of Terms and Acronyms
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ACO |
Aircraft Control Officer |
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AFB |
Air Force Base |
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AFRPL |
Air Force Rocket Propulsion Laboratory |
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AOS |
Acquisition of Signal |
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AP |
Ammonium Perchlorate |
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APU |
Auxiliary Power Unit |
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ARS |
Auxiliary Rescue and Salvage |
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ARTC |
Air Route Traffic Control |
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ASK |
Airborne Support Equipment |
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ASR |
Auxiliary Submarine Rescue |
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BET |
Best Estimate of Trajectory |
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BRD |
Booster Recovery Director |
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BSM |
Booster Separation Motors |
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CASP |
Computer Assisted Search Program |
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CCAFS |
Cape Canaveral Air Force Station |
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CDF |
Confined Detonating Fuse |
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CEP |
Circular Error Probability |
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cg |
Center of gravity |
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CG |
Coast Guard |
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CGC |
Coast Guard Cutter |
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CINCLANT |
Commander-in-Chief, Atlantic Fleet |
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CW |
Continuous Wave |
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dBsm |
Decibels relative to one square meter |
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DDMS |
Department of Defense Manager STS Contingency Support Operations |
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DDT |
Deflagration - Detonation Transition |
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DEG |
Degree |
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DOD |
Department of Defense |
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DPDE |
Data Playback and Digitizing Equipment (video) |
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E&I |
Electrical and Instrumentation |
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EPDM |
Ethylene Propylene Diene Monomer |
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EOD |
Explosive Ordnance Disposal |
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ESMC |
Eastern Space and Missile Center |
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EST |
Eastern Standard Time |
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ET |
External Tank |
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ETA |
External Tank Attach |
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ETR |
Eastern Test Range |
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FAA |
Federal Aviation Administration |
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FDIR |
Fault Detection, Isolation, Recovery |
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fps |
Feet per second |
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fps |
Frames per second |
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FRSI |
Felt Reusable Surface Insulation |
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FSW |
Feet Salt Water |
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FTD |
Foreign Technology Division |
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GH2 |
Gaseous Hydrogen |
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GMT |
Greenwich Mean Time |
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GN&C |
Guidance, Navigation, and Control |
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GPS |
Global Positioning System |
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GO2 |
Gaseous Oxygen |
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HAZ |
Heat Affected Zone |
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HP |
Hewlett Packard |
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HPU |
Hydraulic Power Unit |
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HQS |
Headquarters |
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I/T |
Intertank |
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IEA |
Integrated Electronics Assembly |
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IFLOT |
Intermediate Focal Length Optical Recorder |
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IGOR |
Intercept Ground Optical Recorder |
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ISL |
Inter Surface Line |
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IUS |
Inertial Upper Stage |
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JCS |
Joint Chiefs of Staff |
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JSC |
Johnson Space Center |
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JSL |
Johnson Sea Link |
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KNOTS |
Nautical miles per hour |
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KSC |
Kennedy Space Center |
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LAT |
Latitude |
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Ibs |
Pounds |
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LC |
Launch Complex |
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LCD |
Launch Countdown |
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LCU |
Landing Craft Utility |
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LH |
Left Hand |
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LH2 |
Liquid Hydrogen |
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LO2 |
Liquid Oxygen |
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LONG |
Longitude |
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LORAN |
Long Range Navigation |
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LORAC |
Long Range Accuracy |
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LOS |
Loss of Signal |
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LOV |
Loss of Visibility |
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LPS |
Launch Processing System |
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LRD |
Launch Recovery Director |
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LRD |
Landing Recovery Director |
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LSC |
Linear-Shaped Charge |
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LSO |
Launch Services Organization |
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LWT |
Light Weight Tank |
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m/s |
Meters per second |
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M/V |
Motor Vessel |
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MARISAT |
Marine Satellite Communications System |
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MCBR |
Mobile C-Band Radar |
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MDM |
Multiplexer-Demultiplexer |
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MIGOR |
Mobile Intercept Ground Optical Recorder |
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MOM |
Marine Operations Manager |
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MPS |
Main Propulsion System |
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MSFC |
Marshall Space Flight Center |
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NASA |
National Aeronautics and Space Administration |
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NITE |
N-Internal Trajectory Estimation Program |
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nm |
Nautical mile |
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NMCC |
National Military Command Center |
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NR-1 |
Navy Research Submarine |
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NS |
Nuclear Shuttle |
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NSI |
NASA Standard Initiator |
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NTSB |
National Transportation Safety Board |
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OMI |
Operations Maintenance Instructions |
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OMS |
Orbital Maneuvering Subsystem |
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OPCONCEN |
Operations Control Center |
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OSC |
On-Scene Commander |
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OSL |
Outer Surface Line |
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OV |
Orbiter Vehicle |
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P/L |
Payload |
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PAL |
Protuberance Aerodynamic Load |
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PAN AM |
Pan American Airlines |
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PBAN |
Polybutadiene Acrylonitrile |
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PDL MIGOR |
Ponce de Leon Metric Intercept Ground Optical Recorder |
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PDV |
Peak Detected Video |
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PIC |
Pyro Initiator Circuit |
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PRF |
Pulse Recurrence Frequency |
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R/V |
Research Vehicle |
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RADM |
Rear Admiral |
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RAE |
Range/Azimuth/Elevation |
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RAPP |
Radar Position Program (Computer Program 331) |
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[O13] |
RAPS Right Aft Propulsion System |
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RCA |
Radio Corporation of America |
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RCS |
Radar Cross Section |
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RCS |
Reaction Control System |
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RF |
Radio Frequency |
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RGA |
Rate Gyro Assembly |
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RH |
Right Hand |
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ROM |
Rough Order of Magnitude |
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ROTI |
Recording Optical Tracking Instrument |
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ROV |
Remote Operating Vehicle |
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RSB |
Rudder Speed Brake |
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RSO |
Range Safety Officer |
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RSS |
Range Safety System |
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RTI |
Range/Time/Intensity (video) |
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S/N |
Serial Number |
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S/N |
Signal-to-Noise Ratio |
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SAR |
Search and Rescue |
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SARTEL |
Search and Rescue Telephone Network |
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SEM |
Scanning Electron Microscope |
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SITREPS |
Situation Reports |
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SLA |
Sprayable Light Ablator |
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SOC |
Support Operations Center |
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SOG |
Speed Over Ground |
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SONAT |
Southern Natural Coast Oil Company |
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SPC |
Shuttle Processing Contract |
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SRB |
Solid Rocket Booster |
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SRM |
Solid Rocket Motor |
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SRO |
Supervisor Range Operations |
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SSME |
Space Shuttle Main Engine |
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SRR |
Search, Recovery and Reconstruction |
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STA |
Station |
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STS |
Space Transportation System |
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SUPSALV |
Supervisor of Salvage (USN) |
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TCAR |
Tracking Camera Automatic Reduction (Computer Program 017) |
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TDRS |
Tracking and Data Relay Satellite |
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TDRSS |
Tracking and Data Relay Satellite System |
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TPS |
Thermal Protection System (SRB, ET, or Orbiter) |
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TV |
Television |
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TVC |
Thrust Vector Control |
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UCS |
Universal Camera Site |
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UHF |
Ultra High Frequency |
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US |
United States |
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USAF |
United States Air Force |
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USCG |
United States Coast Guard |
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USCGC |
United States Coast Guard Cutter |
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USN |
United States Navy |
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USS |
United States Ship |
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VAFB |
Vandenberg Air Force Base |
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VHF |
Very High Frequency |
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WGS |
World Geodetic System |
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WSMC |
Western Space and Missile Center |
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x |
Power of magnification |
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Fish |
Towed Sonar Cylindrical Tube (sensor) |
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Pinger |
Homing Device (Short-range acoustic transmitter) |
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Starboard |
Right Side |
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Tracor |
U.S. Navy Contractor |
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WD-40 |
Brand name of product for corrosion protection |
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Zulu |
Greenwich Mean Time (GMT) |
During the first few minutes following the Mission 51-L Shuttle Mishap, the DOD Manager's STS Contingency Support Operations Center (SOC) alerted appropriate search and rescue operations and established communications with the National Military Command Center (NMCC) as well as the Joint Chiefs of Staff WCS). The JCS formed a Shuttle Response Cell which was briefed on the situation.
During the first fifteen (15) minutes following the mishap, search and rescue aircraft and ships were dispatched to holding points short of the safety zone established for falling debris. During this period, one aircraft reported sightings of falling debris impacting the ocean surface. The two SRB retrieval vessels, Liberty Star and Freedom Star, were directed from launch support positions to the impact area.
At 1737Z (1237 EST), the Range Safety Officer gave a clearance for aircraft to enter the safety area.
By 2130Z (1630 EST), a major Search and Rescue (SAR) effort was requested. By 2400Z (1900 EST), twelve (12) aircraft and eight (8) ships were participating in the area of debris impact.
On February 5, 1986, the Coast Guard sent a notice to mariners declaring the search area a safety area, which suspended all fishing operations in the area. This was done because numerous scallop boats reported finding Shuttle debris in their nets.
The Surface Search and Rescue effort continued until February 7, 1986. Debris recovered by the ships assigned to the effort was brought into Port Canaveral and off-loaded. Debris found off the coast of Georgia and South Carolina was returned to the Cape Canaveral Air Force Station (CCAFS).
During the period of January 28, 1986 through February 7, 1986, the Search and Rescue Operation was simultaneously supported with as many as 14 ships and 11 aircraft. The Coast Guard stated, "The operation was the largest surface search in which they had participated."
B. Metric Data (Radar and Optics)
The source materials for this section were two Eastern Space and Missile Center (ESMC) reports, "Radar Data Analysis and Impact Estimation for STS 51-L Debris," Report No. 82-SR-86-06, dated 7 March 1986, Enclosure 2, and "STS 51-L Right SRB," Report 82-SR-86-07, dated 4 April 1986, Enclosure 3.
The prime purpose of evaluation of the metric data (radar/optics) was to provide impact locations for debris recovery and, when possible, identify the tracked object.
Following the breakup of the External Tank (ET) at T+74 seconds, the right Solid Rocket Booster (SRB) continued under thrust for approximately 37 seconds. It was tracked continuously by Radar 1.17 and the Ponce de Leon Metric Integrated Ground Optical Recorder (PDL MIGOR). Radar 0.14 and the Universal Camera Site (WCS) #15 Intermediate Focal Length Optical Tracker (IFLOT) tracked briefly.
Figure 1 shows the geographical locations of the radar and optical stations as well as the track of the right SRB Aft skirt with a short section of SRB segment and impact points of other SRB debris.
Analysis of the PDL MIGOR video tape shows the right-hand SRB, following the ET breakup, to be rolling clockwise viewed from aft approximately once every 10 seconds. Possibly this period decreased by about 1.5 seconds during the 3i seconds of powered flight indicating an angular acceleration about the longitudinal axis.
From T+93.6 to T+95.8 seconds, Radar 0.14 detected a number of small objects separating from the main target. None of these objects was visible to the optics sites or on the radar boresight video tape. Enough data could be extracted to permit a trajectory estimate to be made for one of these objects, designated RD on Figure 1. Impact was at approximately T+ 398 seconds, and the separation speed relative to the main SRB body was on the order of 60 meters per second (m/s).
[O14] At T+110.3 seconds, Range Safety issued a command destruct to the SRB's. The shock wave from the destruct explosion of the right SRB was visible on the WCS-15 E-705 16mm camera, permitting a computed estimate of the explosion at time T+110.275 seconds. The propagation speed of the shock wave was on the order of 1,000 m/s during the first few hundredths of a second with the expansion slowing to essentially zero within 0.1 second.
Following the command destruct, the SRB separated into a number of fragments. Optical resolution was not sufficient to permit the identification of these fragments. Radar 1.17 and PDL MIGOR continued to track a large piece later identified as part of the aft segment and skirt. A number of smoke trails, possibly two dozen small (pinpoint) glowing objects and four bright glowing objects, could be seen on the WCS-15 IFLOT 70mm film. The four bright glowing objects and possibly three smoke trails were also seen on the PDL MIGOR video tape. The radar boresight video tape showed no visible object after the command destruct.
Because the smoke trails are at the limit of the PDL MIGOR video resolution, first priority was given to the three bright glowing objects not tracked by Radar 1.17. Triangulation on these objects (RA, RB, and RC) was possible for periods of four (4) to six (6) seconds, and impact trajectories have been generated. Figure 1 is a map showing the ground traces of the tracked (solid) and projected (dotted) trajectories. Separation speeds relative to the booster aft segment ranged from 45 m/s to 120 m/s.
From T+115 to T+141 seconds, an object flashing twice per second was in the PDL MIGOR field of view. Although it appears near the tracked segment, it cannot be positively linked to the right SRB.
The Federal Aviation Administration (FAA) radar observations cannot be positively associated with the right or the left SRB. The six impact estimates may be from either source, but Objects 2, 5, 6, and 7 appeared more likely to be from the right SRB.
Estimated impact locations of nine objects were determined using the ESMC radar data only. The impact locations are shown on Figure 2.
1. Object A's impact location was of prime importance as it represented debris from the right SRB.
2. Two objects (F and G) were parachutes believed to have been picked up during the surface search. Note: One drogue chute was recovered during the surface search. The right-hand main chutes were recovered with the right-hand SRB forward skirt.
3. Two objects (B and D) were believed to be sizeable (2 to 5 meters, 6 to 16 feet) based on radar boresight recordings and were believed to be dense based on their early impact times.
4. One object (K) was relatively dense but the cross-section was less than 0.1 square meter (1.1 square feet).
5. Two objects (C and I) had moderately slow final descent rates of about 134 feet per second (41 meters per second) with Object C having a relatively large cross-section.
6. Object H was of little interest for recovery operations since it appeared to be a small, light object which may very well have floated after impact.
Both of the reports estimated impact locations of Shuttle-related debris thought to be from the SRB's. Data from both reports support the impact location of the right SRB aft skirt with partial segment attached, reference Figure 2, Object "A" and Figure 1, Point "R".
1. The Supervisor of Salvage, Charles A. Bartholomew, Captain, U.S. Navy, with the assistance of the SRB Incremental Recovery Group lead by Alexander A. McCool, Director, Structures and Propulsion Laboratory, MSFC, directed the Search and Recovery Operation. This section and the next two sections describe the methods utilized during this operation. A more detailed description is contained in Enclosure 4, Search, Classification, and Recovery, and Enclosure 5, SRB Incremental Recovery Planning.
The planning for an underwater salvage operation is dependent upon a changing set of contact data, priorities, and environmental conditions. By utilizing the data available, the proper assets were acquired and effectively utilized (see Table 1 for assets used). The search, contact classification, and recovery phases were accomplished concurrently.
Table 1. Search and Salvage Vessel Assets and Capabilities.
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Platform |
Ship Specifications |
Search/Salvage Assets |
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The Supervisor of Salvage held daily meetings with NASA, DDMS, ESMC, and Coast Guard personnel to determine priorities and deployment of assets. All phases of the operation were discussed with alternatives planned if conditions changed.
Radar data (both ESMC and FAA) were used to establish the basic search area, a parallelogram 10 miles by 25 miles, 5 miles on each side of the major radar tracks. Water depth was just under 100 feet to approximately 1200 feet. The area was completely within the Gulf Stream. The area was later expanded to include the entire right and left hand SRB debris fields based on refined analyses of trajectory data (reference Figure 1). The expanded search area was 480 square nautical miles (307,200 acres) in size. Figure 3 is a map of the search area.
2. The Global Positioning System (GPS) was selected to be used as the primary navigation system. LORAN-C and LORAC-A were also used but corrected using GPS as a standard to adjust for inaccuracies between systems.
The search area was mapped for targets by side scan sonar. This is a device towed by a ship 15 meters (49 feet) above the ocean bottom at a constant speed (between 2 to 4 knots). In order to maintain a constant speed while moving within the Gulf Stream, most mapping runs were made north to south against the current. This extended the operation because no data was gathered on the return trip (to the north).
Search lines 5 seconds longitude apart (135 meters, 148 yards) were used to provide sufficient overlap of bottom surface coverage. Sonar scan width was 300 meters (328 yards). This provides for 118 % overlap. This is done to prevent any voids based on navigation systems inaccuracies, sea conditions, and winds. Through May 1, 1986, a total of 691 contacts have been identified using side scan sonar.
Contact classification was accomplished by documentation and small debris provided by divers (many), remotely-operated submersibles (2), and manned submersibles (2). This documentation consisted of still photographs, video tapes, audio descriptions from manned submersibles, and diver descriptions. Small pieces from debris fields were recovered in an effort to determine a possible general location of adjacent components. Each contact was classified as Shuttle-related, non-Shuttle-related, or unconfirmed. The Shuttle-related were put into categories of each element: Orbiter, ET, Right SRB, and Left SRB.
The majority of the contacts were classified as non-Shuttle-related. These items were Geological, such as shells, coral ridge lines, fish, debris of previous unsuccessful launches from CCAFS, and discarded equipment from vessels using the shipping lane, such as refrigerator, 55-gallon drums, coils of wire.
Through May 1, 1986, 490 contacts have been classified; 408 contacts have been non-Shuttle, while 82 contacts have been Shuttle-related (5 to 1 ratio).
During the contact phase, photos, video tapes, and divers' logs were examined to determine what techniques were to be used for recovery. Special tools were designed and fabricated. The variety of tools ranged from large baskets to contain small pieces in dense debris fields to attach fittings used to lift pieces of SRB weighing up to 15 tons.
Special individual plans were prepared to recover pieces of SRB. This was done to prevent or minimize any handling damage and provide instructions for preservation to prevent additional corrosion. These plans are listed in Enclosures 4 and 5 with an example included in Enclosure 5.
Again, the daily meetings held by SUPSALV were used to establish the priorities and dispatch assets for contact recovery. This was invaluable as it provided a forum to redirect assets as priorities changed.
Divers were used extensively for recovery operations in shallow water. Only surface-supplied air and scuba diving techniques were utilized. Surface-supplied mixed gas (helium/oxygen) and saturation mixed gas (helium/oxygen) diving techniques were not used in the initial search effort. However, this technique is planned to be used later in depths of approximately 300 feet.
The submersibles were used in the deeper water areas.
Table 2 lists the major debris recovered. This operation utilized the largest number of assets ever assembled for marine salvage.
Table 2. Summary of Underwater STS 51-L Contacts Recovered.
|
System |
Contact Number |
Remarks |
|
| ||
|
Right SRB |
0021 |
Aft Segment Skirt |
|
|
0131 |
Aft Center Segment w/Burn Area |
|
|
0195 |
Forward Aft Center Segment |
|
|
0292 |
Forward Aft Segment |
|
|
0301 |
Aft Forward Segment |
|
|
0325 |
Aft Center Segment |
|
|
0433 |
Aft Center Segment |
|
|
0502 |
Forward Center Segment |
|
|
0538 |
Forward Skirt and Parachute |
|
|
0579 |
Aft Segment |
|
|
0615 |
Forward Center Segment |
|
|
0712 |
Aft Segment w/Burn Area |
|
| ||
|
Orbiter |
0008 |
Hydraulic Lines |
|
|
0010 |
Engine Parts |
|
|
0023 |
Engine Parts |
|
|
0030 |
3' Cable Tray Exit |
|
|
0066 |
Main Orbiter Engine Nozzle |
|
|
0068 |
Aft Fuselage |
|
|
0071 |
Miscellaneous Small Hardware |
|
|
0072 |
Miscellaneous Medium Hardware |
|
|
0077 |
Medium Sidewall Piece |
|
|
0078 |
Medium Cone Shape |
|
|
0192 |
Large Hydrazine Tank |
|
|
0520 |
Left Aft Fuselage |
|
|
0530 |
Vertical Stabilizer |
|
|
0555 |
External Large Piece |
|
|
0558 |
Engine Nozzle |
|
|
0564 |
Aft Cargo Hold |
|
System |
Contact Number |
Remarks |
|
| ||
|
|
0566 |
Right Wing |
|
|
0567 |
Electronics and Wiring |
|
|
0568 |
Left Fuselage Sidewall |
|
|
0572 |
External Medium Piece |
|
|
0595 |
Large Left Wing Piece |
|
|
**** |
Crew Compartment |
|
|
**** |
Orbiter Cargo |
|
|
**** |
Orbiter Cargo |
|
| ||
|
Left SRB |
0011 |
Forward Aft Segment |
|
|
0026 |
Forward Aft Center Segment |
|
|
5124 |
SRB External Tank Strut |
|
| ||
|
External Tank |
0003 |
External Small Pieces |
|
|
0004 |
External Medium Piece |
|
|
0029 |
External Large Piece |
|
| ||
|
Booster, Unknown Side |
0196 |
External Tank Attachment w/Clevis |
|
|
0214 |
Large Curved External Piece |
|
|
0312 |
Large External Piece |
|
|
0468 |
Large External Piece |
|
|
0487 |
Large External Piece w/Clevis |
|
|
0510 | |