Approximately 11:39 a.m. eastern standard time (EST) (01:13 mission elapsed time (MET)) on January 28, 1986, the Space Shuttle Challenger experienced vehicle breakup. Preliminary investigation teams were activated within the hour. On March 6, 1986, Mr. Tommy W. Holloway was notified by teleconference of the establishment of the Mission Planning and Operations Team (MPOT) of the Space Transportation System (STS) 51-L Data Design and Analysis Task Force. The letter appointing him Lead and Mr. Harold Draughon, Deputy, along with the general assignment for the MPOT, is contained in section II of this report. The primary task of this team was to respond to the needs and interests of the Mission Planning and Operations Panel of the Presidential Commission on the Space Shuttle Challenger Accident. Additionally, the team was tasked to undertake a critical review and analysis of the National Space Transportation System (NSTS) mission planning, mission operations team functions, flight rate, and flight scheduling, and to determine what effects these activities had on the STS 51-L accident.
The scope of this investigative effort was limited due to the lack of time to permit in-depth, thorough review and analysis. The basic report of findings are in section V of this report with selected backup technical reports included as appendices. The major findings and conclusions are in section VI. Additional data and reports are provided in section VII. Also, presentations, documents, and material provided to the Commission Panel are listed in section III.
The data in this report will show that the STS 51-L mission was a typical STS mission with nothing in the mission operations reconfiguration out of the ordinary. From the period of time during the prelaunch countdown and launch until the vehicle breakup, there was no mission operations abnormality. Also, there was no survival action possible to the STS 51-L crew or possible action the Mission Control Center (MCC) flight control team could have taken to assist the crew.
Data made available during this investigation showed that, in the areas of NSTS mission planning and NSTS flight rate and flight scheduling, although 1985 was considered a very successful year, meeting the milestones for 1986 was going to be a difficult goal.
There is an indication of the need to reevaluate the baseline operational goals for the STS in light of today s program resources.
The findings of this report support the contention that the NSTS had done a commendable job in the areas reviewed prior to the STS 51-L accident. The findings also suggest that careful consideration should be given to assessing flight rate buildup strategy for implementation before Space Shuttle flights resume.
II. General Assignment Letter.
March 20, 1986
51-L DATA AND DESIGN ANALYSIS TASK FORCE
TO: T. Holloway
FROM: Task Force Chairman
SUBJECT: Appointment of Lead, Mission Planning and Operations Team
1. By letter of March 11, 1986, Attachment 1, the Acting Administrator delegated to me, as Chairman of the 51-L Data and Design Analysis Task Force, the power to designate 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 Mission Planning and Operations Team of the Task Force and assign you to be the Lead for that Team. The duties, functions and responsibilities of that 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 your Deputy Lead to act for you as you see fit with or without your being present at the Team's regular office at KSC.
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 aspects of Team activity.
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
[J3] General Assignment for Mission Planning and Operations Team.
The Mission Planning and Operations Team shall perform, as a priority task, the Task Force efforts needed to respond to the needs and interests of the Mission Planning and Operations Panel of the Presidential Commission. The Team Lead and his deputy shall establish a working relationship with the Commission Panel Leader consistent with the procedures of the Task Force and the Commission.
The Mission Planning and Operations Team shall undertake a critical review and analysis of the NSTS mission planning. The purpose of the review and analysis is to ascertain the adequacy of this program activity. The Team shall focus on relevant areas of interest such as the following:
1. Flight planning capabilities as constrained by current resources and schedules.
2. Schedule pressures and impacts.
3. Expansion of the developed flight envelope.
4. Mission planning preparedness.
The Team shall assist the Commission in its investigation of mission planning so as to determine if there were any aspects of mission planning that could have contributed to the STS 51-L accident.
The Mission Planning and Operations Team shall undertake a critical review and analysis of the NSTS Mission Operations Team functions and a qualitative assessment of their performance. The purpose of this review and analysis is to ascertain the adequacy of this program activity.
The Team shall focus on relevant areas of interest such as the following:
1. Flight operations capabilities.
2. Flight operations preparedness.
3. Flight procedures adequacy and maturity.
4. Range safety requirements.
5. Mission operations safety.
The Team shall assist the Commission in its investigation of the Mission Operations Team so as to determine what effect the Mission Operations Team had on the STS 51-L mishap.
The Mission Planning and Operations Team shall undertake a critical review and analysis of the NSTS flight rate and flight scheduling. The purpose of the review and analysis is to ascertain the adequacy of this program activity.
The Team shall focus on relevant areas of interest such as the following:
1. Technician and engineer workload.
2. Flight controller training adequacy.
3. Adequacy of time allotted to mission design and development.
4. Hardware and software testing program content changes.
5. Postponement of repairs, modifications, and software changes.
6. Effects of flight rate coupled with other programmatic pressures on mission planning and mission operations.
The Team shall assist the Commission in its investigation of flight rate and flight scheduling so as to determine what effect these factors had on the STS 51-L mishap.
III. Organization/Method of Investigation.
The day following the Data Design and Analysis Task Force (DDATF) introduction meeting at NASA Kennedy Space Center (KSC) (March 10, 1986), the Lead, Mission Planning and Operations Team (MPOT) called an organizational meeting to assign actions for the Presidential Commission Panel visit the following day. At that time, it was decided to subdivide the work effort for the team into 16 working groups (fig. 1), each group to perform data gathering activities (1) to support the work of the Mission Planning and Operations Panel (MPOP) to the Presidential Commission, and (2) to determine if any organization or functional area of the National Space Transportation System (NSTS) had had an effect on the Space Transportation System (STS) 51-L accident. An administrative/executive support working group was established to develop administrative procedures for the team and take action on any otherwise unassigned action items. Policies and procedures for the MPOT as well as protocol for presentations to the MPOP were established. An action tracking system and a secure filing system were set up, and a special MPOT runner system was activated with the assistance of the Mission Operations Directorate (MOD) Flight Data File (FDF) Branch. To accommodate comparisons of like sources of data in evaluating norms and trends, an evaluation STS flight set was established consisting of STS 5, 6, 7, 41-DR, 41-G, 51-A, 51-F, 51-I, 61-A, 61-B, and 61-C. By the end of the first week of activity, Leads had been assigned for each working group. The group leads were provided with a packet containing:
The investigative work to be conducted by each working group was defined by either a DDATF/MPOT action item assignment or work plan implementation. All investigations were scoped down to consider only factors relating to NSTS mission planning or NSTS mission operations since other DDATF Task Teams were assigned to consider such areas as failure analysis and launch systems and processing analysis.
Meeting with the Mission Planning and Operations Panel
From mid-March through mid-April 1986, a series of meetings were held between the Mission Planning and Operations Panel of the Presidential Commission and the Mission Planning and Operations Team of the NASA Task Force. The following comprises a list by date of the topics covered by formal presentations.
- [J5] b. Software
- c. Manifesting
Material provided to the Mission Planning and Operations Panel
The following material was requested by and given to the Mission Planning and Operations Panel of the Presidential Commission during the course of their investigation.
1. Documents
a. A complete set of all STS-51-L Flight Requirements Documents
b. Flight Readiness Review Minutes for STS 51-L
c. Cargo Integration Review Minutes for STS 51-L
d. Flight Operations Review Minutes for STS 51-L
e. STS 51-L Flight Operations Team Summary Report
f. Space Shuttle Directives, JSC-20939
g. NASA Handbook 5300.4 (10-2) - Safety, Reliability, Maintainability and Quality Provisions for the Space Shuttle Program
h. Problem Reporting and Corrective Action System Requirements for the Space Shuttle Program - JSC-08126A
i. Procedures for Problem Reporting and Corrective action - JSC-09296
j. Safety Policy and Requirement, NHB 1700.7A
k. Implementation Procedure for STS Payloads System Safety Requirements, JSC-13830A
l. Space Shuttle Payload Design and Development Safety Guidelines and Requirements, JSC-20052, vol. 7
m. Interpretations of STS Payload Safety Requirements, JSC-18798
n. Union/Employer Agreement Between NASA, LBJ and AFL-CIO, Local 2184
o. The JSC Workforce in Profile: FY85
p. Expansion of the Ascent Flight Envelope, TE-86-059
q. STS Flight Software Review, April 21, 1986
2. Miscellaneous Background Data
a. Launch minus one day briefing packages for the Terminal Countdown Demonstration Test and for the Launch for STS 51-L
b. Levels II and III documentation related to changing SRB O-ring seals from criticality IR to 1
c. Minutes of August 1, 1985, Senior Safety Review Board
d. JSC Mission Control Center manning lists for STS 51-J, 51-B, 51-D, and 61-A
e. A summary of past flight techniques as related to first stage aborts, DDATF-86-69
f. A list of STS 51-L accident related JSC documents, ECLSS DDATF-86-33
g. An assessment of the cost of changes made to the 61-C manifest, DDATF-86-49
h. A set of anticipated trajectory parameters for STS 51-L including altitude, speed, Mach number, dynamic pressure, and throttle position, DDATF-86-22
i. A history of Aerospace Safety Advisory Panel
j. A history of the Space Shuttle Crew Safety Panel, NS/86-M017
k. A complete list of STS 51-L systems maintenance and inspection deferrals with rationale
1. A description of all planned abort sites including facilities and deficiencies. DDATF-86-58
m. Design crash loads data for the Orbiter and payloads
n. A complete set of minutes from the Senior Safety Review Board since STS-1
o. The minutes of all Systems Integration Board meetings between December 1, 1982, and July 1, 1983
p. A chronology of events related to assessment of the 61-C brake anomaly and the impact of brake failures on a Dakar Landing, DDATF-86-65
q. A copy of JSC Flight Director Loop voice transcripts of the period immediately prior to until shortly after the STS 51-L launch
r. An overview of the spare parts situation from the JSC perspective, VP3-86-M037
s. An assessment of the impact of the STS operations contract on the JSC workforce, DA-RRR-86-06
t. Report of Working Group on Expansion of the Entry Flight Envelope, DM5-86-24
u. SOPC/SMS Loading/Response to SOPC Support Questions, March 6, 1986.
|
AA |
Associate Administrator |
|
AFB |
Air Force Base |
|
AFSCF |
Air Force Satellite Control Facility |
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ALT |
approach and landing test |
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AOA |
abort-once-around |
|
APU |
auxiliary power unit |
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ASRM |
abort solid rocket motor |
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ATO |
abort-to-orbit |
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ATP |
acceptance test procedure |
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. | |
|
BETT |
bolt extrusion thrust termination |
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BFS |
backup flight system |
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BOP |
Baseline Operations Plan |
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. | |
|
CAP |
Crew Activity Plan |
|
CAPCOM |
capsule communicator |
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CCB |
Configuration Control Board |
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CCF |
Center Computing Facility |
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CDR |
commander |
|
CDR |
Critical Design Review |
|
CI |
Configuration Inspection |
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CIR |
Cargo Integration Review |
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CIRD |
Cargo Integration Review Dry Run |
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CR |
change requirement |
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CRT |
cathode-ray tube |
|
. | |
|
DDATF |
Data Design and Analysis Task Force |
|
DFRC |
Dryden Flight Research Center |
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DOD |
Department of Defense |
|
DPS |
data processing system |
|
DPS |
Data Processing Systems Engineer |
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DR |
discrepancy report |
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. | |
|
EAFB |
Edwards Air Force Base |
|
ECLSS |
environmental control and life support system |
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EOM |
Earth Observation Mission |
|
EOM |
end of mission |
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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 |
|
ETE |
end-to-end |
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ETR |
Eastern Test Range |
|
. | |
|
FAA |
Federal Aviation Administration |
|
FACI |
First Article Configuration Inspection |
|
[J6] FAWG |
Flight Assignment Working Group |
|
FCOD |
Flight Crew Operations Directorate |
|
FCS |
flight control system |
|
FD |
flight day |
|
FD |
Flight Director |
|
FDA |
fault detection and annunciation |
|
FDE |
fluid dynamics experiment |
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FDF |
Flight Data File |
|
FDRD |
Flight Definition and Requirements Document |
|
FOR |
Flight Operations Review |
|
FRD |
Flight Requirements Document |
|
FRR |
Flight Readiness Review |
|
FSL |
Flight Systems Laboratory |
|
FSW |
Flight Software |
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. | |
|
GAS |
Get-Away Special |
|
GMT |
Greenwich mean time |
|
GNC |
guidance and navigation computer |
|
GNC |
guidance, navigation, and control |
|
GPC |
general purpose computer |
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GPS |
global positioning satellite |
|
GSE |
ground-support equipment |
|
GSFC |
Goddard Space Flight Center |
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. | |
|
H2 |
hydrogen |
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HAC |
heading alignment circle |
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HAL |
high-order assembly language |
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HYD |
hydraulic(s) |
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. | |
|
IBM |
International Business Machines |
|
ICAO |
International Civil Aviation Organization |
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IDS |
interface data sheet |
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INCO |
Integrated Communications Officer |
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IUS |
inertial upper stage |
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IVT |
Interface Verification Test |
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. | |
|
JIS |
joint integrated simulation |
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JSC |
Johnson Space Center |
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. | |
|
KSC |
Kennedy Space Center |
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. | |
|
LCC |
Launch Commit Criteria |
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LCC |
Launch Control Center |
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LCIMC |
Logistics Critical Items Management Center |
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LDEF |
long-duration exposure facility |
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LIMS |
Logistics Inventory Management System |
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LOS |
loss of signal |
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LSFR |
Launch Site Flow Review |
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LSSC |
Launch Support Services Contractor |
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. | |
|
MAST |
measurement and stimuli |
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MCC |
Mission Control Center |
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MDRF |
Mission Data Request Form |
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MECO |
main engine cutoff |
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MER |
Mission Evaluation Room |
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MET |
mission elapsed time |
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MILA |
Merritt Island Launch Area |
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MLS |
microwave landing system |
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MMU |
mass memory unit |
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MOC |
missions operations computer |
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MOD |
Mission Operations Directorate |
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MOU |
memorandum of understanding |
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MPESS |
mission peculiar experiment support structure |
|
MPM |
manipulator positioning mechanism |
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MPOP |
Mission Planning and, Operations Panel |
|
MPOT |
Mission Planning and Operations Team |
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MPS |
main propulsion system |
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MRMS |
Mission Requirements Management system |
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MSD |
Mission Support Directorate |
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MSFC |
Marshall Space Flight Center |
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MUR |
Manpower Utilization Records |
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. | |
|
NAV |
navigation |
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NC1 |
nominal correction 1 |
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NHB |
NASA Handbook |
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NLE |
no longer endanger |
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NMI |
nautical miles |
|
n. mi. |
nautical miles |
|
NOM |
nominal |
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NSTS |
National Space Transportation System |
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NSTSPO |
National Space Transportation System Program Office |
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NWS |
nosewheel steering |
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. | |
|
O2 |
oxygen |
|
OASCB |
Orbiter Avionics Software Control Board |
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OFP |
Operational Flight Profile |
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OFT |
orbital flight test |
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OI |
operational increment |
|
OIS |
operational intercommunication system |
|
OMI |
operations and maintenance instruction |
|
OMRS |
Operations and Maintenance Requirements Specification |
|
OMRSD |
Operations and Maintenance Requirements and Specifications Document |
|
OMS |
orbital maneuvering system |
|
OPF |
Orbiter Processing Facility |
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OPT |
operational pressure transducer |
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OST |
Operations Support Timeline |
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OV |
Orbiter vehicle |
|
. | |
|
PAFB |
Patrick Air Force Base |
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PAPI |
precision approach path indicator |
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PASS |
primary avionics subsystem software |
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PC |
chamber pressure |
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PCIN |
program change identification number |
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PCN |
page change notice |
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PEAP |
personnel egress airpack |
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PIP |
Payload Integration Plan |
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PLB |
payload bay |
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PLBD |
payload bay door |
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POWG |
Payload Operations Working Group |
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PPE |
phase partitioning experiment |
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PRACA |
Problem Recording and Correction Action |
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PRCB |
Program Requirements Control Board |
|
PRCBD |
Program Requirements Control Board Directive |
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PS |
payload specialist |
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psi |
pounds per square inch |
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psia |
pounds per square inch absolute |
|
. | |
|
Q |
dynamic pressure |
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. | |
|
RCA |
Radio Corporation of America |
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RCC |
Range Control Center |
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RCN |
requirements change notice |
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RCS |
reaction control system |
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RF |
radio frequency |
|
RFP |
request for proposal |
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RHC |
rotational hand controller |
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RI |
Rockwell International |
|
RIC |
Rockwell International Corporation |
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RID |
review item discrepancy |
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RMS |
remote manipulator system |
|
RSO |
Range Safety Officer |
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RSS |
Range Safety System |
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RTLS |
return to launch site |
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. | |
|
SAIL |
Shuttle Avionics Integration Laboratory |
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SCA |
Shuttle carrier aircraft |
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SIMS |
Shuttle Inventory Management System |
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SLF |
Shuttle Landing Facility |
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SM |
systems management |
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SMS |
Shuttle mission simulator |
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[J7] SMSG |
Shuttle Maintenance and Steering Group |
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SPC |
stored program command |
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SPF |
Shuttle Processing Facility |
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SPF |
Software Production Facility |
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SR&QA |
Safety, Reliability, and Quality Assurance |
|
SRB |
solid rocket booster |
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SRNI |
solid rocket motor |
|
SSD |
Spacecraft Software Division |
|
SSME |
Space Shuttle main engine |
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STA |
Shuttle training aircraft |
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STS |
Space Transportation System |
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STSOC |
Space Transportation System Operations Contract |
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. | |
|
TAL |
transatlantic abort landing |
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TBS |
To be supplied |
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TCDT |
terminal countdown demonstration test |
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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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TISP |
Teacher in Space Payload |
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T/N1 |
telemetry |
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TPS |
thermal protection system |
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TT |
thrust termination |
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TVC |
thrust vector control |
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. | |
|
USAF |
United States Air Force |
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VAFB |
Vandenberg Air Force Base |
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VAL |
value |
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VFR |
visual flight rules |
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VLS |
Vandenberg Launch and Landing Site |
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. | |
|
WSGT |
White Sands Ground Terminal |
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WSNIR |
White Sands Missile Range |
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WTR |
Western Test Range |
V. Mission Planning and Operations Team Report.
Introduction
The findings of the Mission Planning and Operations Team (MPOT) of the Space Transportation System (STS) 51-L Data Design and Analysis Task Force (DDATF) were presented to the Mission Planning and Operations Panel (MPOP) of the Presidential Commission on the Space Shuttle Challenger Accident in a series of eight formal meeting sessions and three data exchange meetings between March 11 and April 15, 1986. Ten of these sessions were at the Lyndon B. Johnson Space Center (JSC) and one at the George C. Marshall Space Flight Center (MSFC). In addition to the formal briefing sessions, the MPOT also provided responses to 38 action items from the MPOP. This report is a synopsis of all the information presented to the panel with emphasis on those areas of the NSTS found to be deficient or in need of possible further analysis. The basic report presents the background data used to make findings and conclusions listed in section VI. The MPOT is well aware that there are some areas of the NSTS organization and functions which are not addressed in this report; they were not overlooked, but were omitted because of lack of time and the lack of any indicators of a need to pursue them.
V.A. STS 51-L Planning and Preparations.
Introduction
Overall, the planning and preparations for Space Transportation System (STS) mission 51-L were very typical of the missions being planned and flown in late 1985 and early 1986. For the most part, the techniques and procedures that were planned to be used during the mission were not new for this flight but were baselined from previous missions. This section uses the flight preparation template as the framework by which to describe the planning and preparations accomplished for STS 51-L, starting with determining the makeup of the flight manifest.
1. Flight Manifest Determination
The original mission for Space Transportation System (STS) 51-L was baselined in the Flight Definition and Requirements Directive (FDRD) dated May 30, 1984. The configuration was
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Primary Payloads: |
TDRS-D/IUS |
|
|
EOS-1 |
|
Secondary Payloads: |
OASIS |
|
|
IOCM |
|
|
GAS |
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Middeck Experiments: |
ARC |
|
|
SSIP |
|
Launch Date: |
July 2, 1985 |
|
Orbiter: |
OV-099 |
Ten FDRD changes applicable to STS 51-L (summarized in table 1 and figure 1) were approved prior to flight. The final configuration consisted of
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Primary Payloads: |
TDRS-B/IUS |
|
|
SPARTAN/Halley |
|
Secondary Payloads: |
None |
|
Middeck Experiments: |
CHAMP, FDE, PPE, TISP, SSIP, RME |
|
Launch Date: |
January 23, 1986 |
|
Orbiter: |
OV-099 |
The NASA crew assignment was released on January 27, 1985, and consisted of the following:
The Teacher in Space Program (TISP) payload specialist (PS), Christa McAuliffe, was added to the crew with a Flight Requirements Document (FRD) change signed on June 13, 1985. Although the PS was on the manifest, her payload was not in the documentation. This editorial correction was made in FDRD change number 126 on January 7, 1986. The Hughes PS, Gregory B. Jarvis, was added to the crew with an FRD change signed on November 11, 1985.
Changes to the payload manifest caused the baseline flight design process to be delayed, which required a launch date slip from the initial early July 1985 date to the final date in late January 1966. After the Cargo Integration Review (CIR) was accomplished, the primary payload manifest was very stable. However, several changes to the secondary manifest occurred after the L-5 freeze point. With the exception of the addition of the PS's as their payloads were added to the manifest, the crew assignment was never changed.
2. Baseline Flight Design
Using the baselined FDRD manifest dated May 30, 1984, the initial Cargo Integration Review Dry Run (CIRD) and Cargo Integration Review (CIR) were scheduled on June 27 and September 4, 1984, respectively. The intent of these reviews was to perform the preliminary engineering assessments and evaluate the conceptual flight design's feasibility. The end product was to baseline the FRD. These review dates were subsequently slipped to August 21, 1984, for the CIRD and October 2, 1984, for the CIR. The CIRD was conducted on August 21, 1984, but the CIR was rescheduled to November 27, 1984, to accommodate the manifest change deleting EOS-1 and adding Aussat 1. This...
[J12]....date was subsequently slipped to December 18, 1984 and slipped again to January 22, 1985. Before the CIR could be held in January, the manifest and the Orbiter assigned both changed. Aussat was deleted, the HS-376 was added, and OV-104 replaced OV-099. The CIR was rescheduled to March 18, 1985, and the launch date slipped from July 2, 1983, to November 27, 1985. Again, prior to this CIR, the manifest, the Orbiter, and the launch date changed, requiring that the CIR be rescheduled to June 18, 1985. The HS-376 was deleted, the Orbiter was changed back to OV-099, and the launch date was slipped to January 22, 1986.
The June 18, 1985, CIR was held on the scheduled date. Table 2 shows the CIR history in graphic form, Even though there were six changes to the CIR date for STS 51-L, due primarily to payload manifest changes, the relationship between the final CIR and the January launch date was according to the planned flight preparation template and the final process worked very smoothly.
3. Flight Product Development
a. Production Milestones
Once the primary payload manifest was stable and the CIR process was completed, the flight design process became relatively straight-forward, with nothing out of the ordinary associated with the STS 51-L mission operations reconfiguration process from a flow management standpoint.
The most noticeable, and potentially significant, result of slips in the production process was to delay the start of flight-specific Shuttle Mission Simulator (SMS) standalone and integrated training. Without a launch slip, the delay in starting training compresses the training activity and increases the crew and flight controller workload in the last month before flight.
The portions of the flight production template that directly involve the Mission Operations preparations are shown in figure 2, along with the planned and actual delivery dates of key production milestones for STS 51-L.
The L-5 month Flight Planning and Stowage Review was conducted on August 20, 1985, with the purpose of addressing any open items and any proposed changes to the existing baseline, and of establishing a finalized set of requirements for STS 51-L. The FRD, Crew Activity Plan (CAP), and flight design/consumables status were reviewed as well as the current status of the engineering integration, photo/TV requirements, and crew compartment stowage. Significant actions resulting from this review included the need for further review of the launch window requirements with the intent to provide a longer launch window, looking at potential tradeoffs to allow carrying the OASIS payload, and the requirement to carefully define and fully document the activities and requirements for the Teacher in Space Program (TISP), which had. not been completely finalized yet. Work on the launch window constraints, particularly the SPARTAN constraints, continued past the Flight Operations Review (FOR). The OASIS was never manifested, and the TISP work was all completed satisfactorily.
b. Flight Data File
The CAP was never published in preliminary form as the publication template has the preliminary CAP produced at L-7.7 months and the CIR was not until L-6.5 months. Instead, since one of the most critical portions, the tracking and data relay satellite (TDRS) deployment timeline, was almost identical with the previous STS 51-E mission, the STS 51-E CAP was used as the baseline document until the STS 51-L basic edition was published at L-4 months. The CAP cycle for STS 51-L was affected by several late manifest changes and incomplete documentation on some of the payloads that were added. Late changes, in this context, are changes to the manifest after the FOR has baselined the payload-related Flight Data File (FDF) and included the addition of CHAMP, FDE, and PPE. Except for CHAMP, these changes were all minor, were within the capability of the system, and were similar to changes on other flights. CHAMP was slightly more difficult to integrate into the timeline because the activities had to be accomplished at very precise times and thus displaced other previously planned activities. The incomplete documentation consisted of Payload Integration Plans (PIP's) for the TISP and PPE. Not having all the payloads' requirements available in the PIP's made integrating payload activities into the timeline impossible until any constraints were identified. The end result was a delay in performing the update to the timeline. The impact of the delay in publishing the final CAP was minimized by delivering the attitude timeline on December 13, 1985, and using the basic edition of the CAP, dated November 15, 1985, for simulations until the final edition was available. Both activities served their purpose well, and, except for the CAP preparation function, there was no impact of the late publication. Table 3 contains a chronology of changes to STS 51-L along with change impact to the CAP and CAP publication dates.
In addition to the CAP, 24 other FDF documents were published in preparation for STS 51-L. Half of the documents published were either flight-specific flight supplements to generic procedures already carried onboard, or flight-specific books published specifically for STS 51-L (such as the IUS Deploy Checklist). The remaining half of the documents published in preparation for the mission were changes and updates to generic procedures that were not necessarily flight specific (such as updates to the Data Processing System (DPS) dictionary and updates to the Medical Checklist). The number of documents published for STS 51-L was fairly typical for missions in that timeframe and was not considered excessive. From an FDF standpoint, STS 51-L was considered a moderately complex flight because of the rendezvous and proximity operations conducted in support of SPARTAN. The procedures were not new, but they did have to be tailored to support the SPARTAN's requirements. The inertial upper stage (IUS) deploy, again from an FDF standpoint, was considered standard because of the fact the procedures had been baselined from STS 6 and STS 51-E. All procedures were validated by January 9, 1986. Changes to the FDF are made via NASA Johnson Space Center (JSC) Form 482. Figure 3 depicts the 482 traffic experienced for STS 51-L as a function of time prior to launch. The traffic was not unlike the customary traffic for similar missions and was well within the capabilities of the system.
The FOR for STS 51-L was conducted on October 22 to 24, .1985, to review the payload-related FDF and associated mission documentation and to note discrepancies against the documentation. At that time, 235 discrepancies were submitted: 166 were approved, 2 were disapproved, and 67 were withdrawn. There were no major procedure changes in any of these discrepancies, with the majority of changes consisting of editorial and format changes. As a result of the FOR, 13 action items were generated. Those of significance included tasking JSC and NASA Goddard Space Flight Center (GSFC) to develop procedures for conducting a backup SPARTAN mission with the SPARTAN still in the bay (i.e., it could not be deployed), and also tasking the STS Program Office and GSFC to determine the earliest launch time for the period from January 22 through January 30, 1985, and to set the planned STS 51-L launch time and window. The SPARTAN in-the-bay procedures were completed, verified, and practiced by the crew, and the launch window issue was finalized by the time of the Flight Readiness Review (FRR).
In summary, the FDF was complete and ready for flight. The number of changes processed late (post-FOR) was well within the system's capability and were primarily due to manifest changes and refinements in the SPARTAN rendezvous and malfunction procedures. The number of changes processed was also fairly typical of missions being flown in that timeframe.
c. Flight Rules
The STS 51-L Flight Rules consisted of the generic All Flights Rules and the STS 51-L Flight-Specific Rules Annex. The All [J13] Flights book used was dated December 16, 1985, and had one pen and ink change posted (dated January 23, 1986). The Flight Rules Annex containing the STS 51-L flight-specific rules was first published as a preliminary edition prior to the FOR. After the FOR, a final edition dated December 20, 1985, was published which incorporated the updates agreed upon in the FOR with any open items being reserved for a page change notice (PCN). Some open items were closed later than anticipated, so the PCN was held and issued as a pen and ink change. Most open items involved waiting for actual new data to be provided, such as the final ascent targeting numbers and IUS transfer orbit performance estimates. The only open item that also included open work was the decision on where the weather alternate for the transatlantic abort landing (TAL) site would be (Sidi Slimane or Casablanca) and the SPARTAN constraints on the final launch window. All these items were closed and pen and ink change I was published on January 20, 1986. In the last few days prior to launch, a second pen and ink change was published, dated January 24, 1986, that further refined some trajectory and guidance rules and some SPARTAN latching definitions, but none were controversial or involved. One IUS issue was worked before flight that was not published in the Flight Rules Annex, but it did have an approved change request completed. The topic of the change request was IUS deploy without cable tray separation. The Safety Office participated in the review of this rule change, and an approved rule wording was agreed upon in a teleconference between all interested parties. The crew was briefed on the rule change and understood and agreed on its contents. The rule change will be incorporated in the baseline rules for the next IUS mission.
d. Flight Techniques and Payload Operations Meetings
There was only one Orbit Flight Techniques meeting for STS 51-L. The Orbit Flight Techniques meeting was conducted on December 6, 1985, and baselined the forward reaction control system (RCS) separation technique to be used, if needed, for the IUS deploy, and several procedural topics concerning SPARTAN deploy and retrieval, and the SPARTAN in the bay mission. Following this Orbit Flight Techniques meeting, no unresolved issues or controversial topics were left open and the only action items concerned implementing the procedures baselined in the meeting. Additional Orbit Flight Techniques meetings were not required because the nature and agenda of the Payload Operations Working Group (POWG) meetings allowed most on-orbit topics to be worked in those forums.
Five Ascent/Entry Flight Techniques meetings were held in the 12 months prior to STS 51-L. None of these meetings addressed any STS 51-L flight-specific topics.
One IUS/TDRS POWG was conducted August 23, 1985, for STS 51-L. From an IUS/TDRS standpoint, very few new topics were to be worked for STS 51-L since most issues had been worked for STS 51-E, which was the baseline for STS 51-L. Topics of interest discussed included the use of a star scan attitude update technique for the IUS, when the "GO" for deploy should be given to the crew, the criteria for making the decision to deploy, and the data rates at which the IUS and the Orbiter would transmit telemetry while on orbit.
Two SPARTAN 203 (SPARTAN-Halley) POWG's were held for STS 51-L. The first, held on November 29 and 30, 1984, served to review the SPARTAN 203 requirements and to address and accelerate the baselining of the SPARTAN 203 PIP annexes. The SPARTAN 101 mission, flown on STS 51-G, was the baseline for SPARTAN 203. The second SPARTAN POWG was conducted on August 20 and 21, 1985, where the details of the operations aspects of the SPARTAN mission were reviewed and some configuration details were decided (such as the color coding of the reflectors, etc.). Final details of the FDF procedures continued in development up through the FOR. The exact techniques and formats for programming the SPARTAN microprocessor and for performing the SPARTAN "in-the-bay" mission were worked out in several informal meetings among the crew, the SPARTAN engineers, and the flight controllers at JSC.
The small number of Flight Techniques and Payload Operations Working Group meetings dedicated to STS 51-L reflected the generally high level of maturity of the techniques and procedures that were planned for STS 51-L. All the TDRS-related procedures had been baselined from earlier missions. The SPARTAN-Halley procedures were baselined from standard deploy and rendezvous techniques also flown on earlier missions, but with the SPARTAN-Halley unique requirements folded in. None of the middeck experiments required any new Orbiter specific procedures to support their conduct; however, the payloads themselves had their own specific procedures. The ascent and entry procedures were all standardized procedures with STS 51-L flight-specific performance figures.
4. Training
The crew completed all required training for STS 51-L. Table 4 lists the planned and actual hours spent in both crew training and integrated simulations. These hours do not reflect self-study hours (i.e., workbook, etc.). Higher than required hours indicates that a lesson may have taken longer than planned or that the crewmember repeated the lesson for review. All required lessons were completed. Less than required hours does not indicate omission of lessons. Rather, it indicates a lesson was completed in less time than planned.
All of the NASA crewmembers, except for Michael Smith, had previously flown a Space Shuttle mission. Michael Smith had started the training cycle with the STS 51-C crew when he was to be a replacement for a crewmember who had a possible physical problem. However, STS 51-L was his first flight.
The crew started their Single Systems Trainer (SST) training at L-37 weeks. Generic Shuttle Mission Simulator (SMS) standalone training started at L-36 weeks, and flight-specific SMS standalone training started at L-9 weeks. The distribution of the crew's training workload from L-9 weeks to launch is shown in table 5, which also breaks the training workload down into formal (scheduled) training in the SMS and other simulators and informal (unscheduled) training and also includes Shuttle training aircraft (STA) flying hours in parentheses.
Integrated training allows the crew to train with the flight controllers in the Mission Control Center (MCC) and in remote control centers. The SMS generates the telemetry for the control centers just as the real Orbiter does. The integrated training for STS 51-L was divided into ascent and entry training, which was run with the ascent and entry teams in the MCC, and on-orbit simulations, which were run with the flight control team that would be on duty during the portion of the flight being simulated. The orbit simulations included three TDRS deploy simulations, one SPARTAN deploy simulation, and two SPARTAN rendezvous simulations. Also included in the orbit simulations was a "systems" simulation for the MCC planning team and a deorbit prep and entry simulation for the entry MCC team. The TDRS flight control team at the White Sands Ground Terminal (WSGT) in Las Cruces, New Mexico, and the IUS flight control team at the Air Force Satellite Control Facility (AFSCF) in Sunnyvale, California, participated in all three TDRS deploy integrated simulations (which are referred to as joint integrated simulations (JIS's) when remote sites participate). The SPARTAN mission management and engineering support personnel were present in the MCC and participated in all SPARTAN integrated simulations. Table 6 summarizes the integrated simulations (including JIS's) for STS 51-L.
The launch date slips for STS 61-C became a scheduling factor for the integrated simulations for STS 51-L. The STS 61-C launch pushed a bow wave of STS 51-L terminal countdown demonstration test (TCDT) and cargo end-to-end (ETE) testing activities at NASA Kennedy Space Center (KSC); these activities required STS 51-L prime crew and/or MCC resources and.....
[J17] ....thereby constrained the time at which integrated simulations could be conducted. The STS 51-L training schedule was changed several times during the last 6 weeks prior to launch due to the launch slips of STS 61-C and the desire to suspend simulations between the Christmas and New Year holidays. Since STS 61-C slipped after the holidays, STS 51-L simulations were rescheduled, but never canceled, to either stay ahead of the STS 61-C bow wave or to fill in behind as STS 61-C continued to slip. The final impact of the STS 61-C launch slips on STS 51-L training was a compression of the spacing between the dynamic phase (ascent and entry) simulations during the last 2 weeks before flight. All the on-orbit simulations were accomplished with typical spacing between the simulations.
The training for the IUS flight control teams at the AFSCF consisted of standalone simulations (AFSCF only), intercenter exercises with the TDRS team at the WSGT, and JIS's with WSGT. JSC, and the crew. The TDRS flight control teams completed the same types of simulations at their facility at the WSGT. A summary of the training planned and complete d at the AFSCF and the WSGT is included in table 7.
Even though slips in the flight production process caused flight specific training to start later than planned, the crew and the flight control teams at all three control centers completed all planned training for STS 51-L and several crewmembers actually completed more than was planned. The effect of the STS 61-C launch slips was to compress the time available for some of the later ascent and entry simulations, but no training time was lost and all requirements were met. The flight crew preparations for STS 51-L were typical and satisfactory and had no effect on the accident.
5. Launch Site Flow
The KSC Launch Site Flow Review, originally scheduled for October 15, 1985, was slipped to October 16, 1985. Its purpose was to baseline the launch site flow activities. Several Orbiter modifications were incorporated into the flow, and three pieces of new/modified flight crew equipment were identified for monitoring to avoid any potential impact to KSC. The Solid Rocket Booster (SRB) history was reviewed, noting all hardware had been flown or used in major ground tests at least once.
KSC's planning for Orbiter Processing Facility (OPF) and pad operations is documented as an "operations assessment." The portions of the assessment supported by the Space Shuttle operations community are shown in figure 4, together with key flow milestones.
Noteworthy payload-related activities in the flow consist of SPARTAN 203 installation into the payload bay on December 9, 1983 (on schedule), and the Interface Verification Test (IVT) on December 10, 1985. Significant IUS/TDRS activities consisted of IUS/TDRS installation into the payload bay on January 5, 1986, with IUS/TDRS IVT being accomplished on January 10 and the cargo ETE test on January 11, 1986. These last activities had to wait until activities associated with STS 61-C launch preparation and the TCDT for STS 51-L were completed. The vehicles were found to be in excellent operating order, as were the control facilities and their interfaces.
The TCDT for STS 51-L, using operations and maintenance instruction (OMI) S0017, was conducted on January 7 and 8, 1986. The launch count for STS 61-C caused some inconvenience for the STS 51-L crew since the crew quarters and other facilities were being used by the STS 61-C crew. Workarounds for these problems were found, and the TCDT went smoothly and provided the crew with an excellent rehearsal of most launch countdown activities.
The mission operations participation in the launch site flow activities was straight-forward and typical of the support provided for similar missions. The schedule for the flow was affected by the STS 61-C launch slips, and eventually affected the launch date, but all flow activity was completed or waivered.
6. Flight Readiness Review
The STS 51-L level I FRR was conducted on January 15, 1986. The agenda consisted of the following:
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I. |
Introduction |
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II. |
Mission Summary - B. R. Stone |
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III. |
System and Cargo Integration - L. G. Williams |
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IV. |
Orbiter/Crew GFE - H. Taylor |
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V. |
SSME/ET/SRB - W. F. Taylor/G. P. Bridwell/L. B. Mulloy |
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VI. |
IUS - S. P. Saucier |
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VII. |
Launch and Landing Operations - J. Harrington |
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VIII. |
SR and QA - B. J. McCarty |
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IX. |
Weather Status - Lt. Funk |
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X. |
Action Items/Readiness Poll |
Agenda items 4 through 8 addressed the flight readiness of the hardware, with all areas confirming that they were ready to fly pending any work still scheduled for completion. Agenda items 2 and 3 addressed the topics most pertinent to Mission Operations Flight Readiness and are the only items discussed in this report.
In presenting item 2, the lead Flight Director, Brock R. Stone, reviewed the mission, discussed the launch window, and presented the Flight Readiness Statements for Mission Operations and the Communications and Data Network. The launch window was a composite of Orbiter, IUS/TDRS, and SPARTAN requirements. Since launch windows are designed to satisfy payload requirements, as manifested payloads were changed the STS 51-L launch time was changed to accommodate mission requirements. The STS 51-L launch originally was scheduled for a morning liftoff. When SPARTAN-Halley was manifested, the launch Window was changed to afternoon.
Launch windows are generally determined by the launch and landing lighting constraints imposed by the Orbiter for the nominal end of mission and the various abort modes, and by the flight-specific requirements imposed by the payload being launched. The Orbiter requirement for a lighted abort-once-around (AOA) landing at Edwards Air Force Base (EAFB) was initially the only lighting constraint. All other landings could be made at night because of the landing aids available at KSC for return to launch site (RTLS and end of mission) and at the primary TAL site, Dakar, Senegal. However, the only available weather alternate to Dakar for a TAL abort was Casablanca, Morocco, which was not equipped for night landings and. therefore, was only available during daylight.
The strategy for determining the launch window for STS 51-L was designed to satisfy SPARTAN-Halley requirements by using an afternoon launch time, at the expense of giving up the TAL weather alternate at Casablanca (because of darkness there), until such time as the SPARTAN-Halley requirements could no longer be met. After that date, the launch time would be moved to the morning in order to regain the TAL weather alternate site. The IUS/TDRS requirements were met for this entire range of launch times in question and were not a factor.
The duration of the window was three hours, which was the maximum allowable time for the crew to remain strapped into their seats during unplanned holds.
The SPARTAN-Halley requirements were to provide at least 90 seconds per orbit of occulted viewing time of Halley's comet. This is the time in each orbit that the comet would still be in view while the Earth occulted the Sun. If this requirement could not be met, the SPARTAN-Halley would still be able to see the comet but the glare from the Sun could have compromised the quality of their data. Because of the comet's motion, the occulted time available at deploy was greater than that available 45 hours later when the SPARTAN was to be retrieved.
The afternoon window was anchored in time by specifying when it would close, and then having it open 3 hours earlier. The closing [J18] time was set as 15 minutes after sunset at the AOA site at EAFB. If the Space Shuttle was launched at the opening of this window, the SPARTAN would not receive the full 90 seconds of occulted time each revolution at retrieve (it would have started at greater than 90 seconds at deploy and, because of the comet's motion, decreased throughout the 45 hour free-flyer mission). The concession was made that if all systems were go at the opening of the window, and were projected to remain that way (i.e., no weather problems closing in), then the lift-off would be held until the 90 seconds at retrieve line was met.
The afternoon launch window required by SPARTAN resulted in a nighttime TAL landing-. This was acceptable at Dakar, Senegal, since Dakar was equipped with a microwave landing system (NILS) and lighted landing visual aids. However, during January, an extended period of unacceptable visibility conditions at Dakar, due to blowing dust, raised major concerns about possible launch delays while waiting for Dakar weather to clear. STS 51-L could not reach the normal TAL weather alternate site at Moron, Spain, because its distance exceeded 51-L abort performance capability. Accordingly, expedited action was taken to implement an alternate TAL site at Casablanca, Morocco. However, since the night landing provisions required by the Space Shuttle were not available there, the site could only be used for launches with daylight TAL landings.
As the launch date became later in the month, the window that allowed SPARTAN to have 90 seconds occulted time decreased to zero. After this date, there was. no reason to still give up the TAL weather alternate site and the launch time was moved earlier in the day to regain Casablanca as the backup TAL site.
So, the strategy initially accepted the risk of delayed launches if there was a wait required for Dakar to clear, in order to ensure that SPARTAN data on Halley's comet was not degraded. However, once the SPARTAN requirement could not be met, then the risk of launch delays possible with no TAL weather alternate available caused the launch time to be adjusted earlier to make Casablanca lighted and, therefore, available. The same technique for determining the end of the morning window was used (i.e., sunset plus 15 minutes) and for the opening of the window (i.e., 3 hours earlier than it closed). The planned date for shifting from the afternoon window to the morning window was to be January 28, 1986.
The morning and afternoon windows were grouped into primary windows and secondary windows. The primary windows were the series of windows from January 25 through January 30, 1986, that the above described strategy defined. The secondary windows were the windows defined by Casablanca lighting during the days that the SPARTAN-Halley requirements were being honored, and the latest lighted AOA when the lighted TAL site was the driver.
Figure 5 lists the primary and secondary launch windows and depicts the launch windows in graphic form.
Mr. L. G. Williams presented agenda item 3, reviewing the Cargo Integration and Payload Safety area, including an assessment of systems margins. No open issues were identified. In reviewing the performance summary, Mr. Williams identified a performance margin of 214 pounds less than the 3( margin with a launch probability of 92 percent. It was pointed out that this was the first launch from pad 39B, and the only open work remaining for Systems Integration was to complete the installation of the middeck payload lockers and to complete the waiver for RTLS and TAL landing weights. The presented performance summary data are listed in figure 6.
Figure 6. STS 51-L FRR Performance Summary Data.
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STS 51-L Launch Performance Data | |
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SRB Sep Altitude (ft): |
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Q Max Nominal (psf): |
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Q Max Dispersed (psf): |
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Q Alpha Nominal Profile |
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Nominal SSME Throttle for Q Control |
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Launch Probability: |
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Payload Weight (lb) |
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Operator Weight (lb) |
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OMS Load (lb) |
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3 a [Greek letter alpha] FPR (lb) |
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Projected Margin: |
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2 a [Greek letter alpha] FPR (lb) |
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Projected Margin |
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Launch Hold Available After L-5 Min (based on - 214 l margin): |
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STS 51-L Downweight Summary | ||||
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Nominal |
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RTLS |
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TAL |
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AOA |
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No Deploy TDRS-B and SPARTAN-H |
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No Deploy TDRS (No FWD RCS Dump) |
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Worst AFT c.g. Case (No Deploy TDRS-B and No SPARTAN Retrieval) |
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Allowable c.g. Limits |
Allowable Landing Weight Limits | |||
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1076.7 < X c.g. < 1109.0 in. |
Nominal: 211 000 lb | |||
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- 1.5 < Y c.g. < 1.5 in. |
* No Deploys and Aborts: 240 000 lb | |||
7. L-1 Day Crew Briefing
The L-1 day crew briefing was conducted on January 24, 1986. The standard format was followed for this briefing, with both the KSC launch team and the JSC flight control team addressing each subsystem and covering its status and any operational constraints or procedural workarounds required. The crew was briefed on main engine/orbital maneuvering system (OMS)/reaction control system (RCS) history with no open problems, and also on the data processing system (DPS) and environmental control and life support system (ECLSS). A hydrogen (H2) tank heater anomaly briefing was given to the crew as was a flow transducer bias for the fuel cell/power reactants storage and delivery system. Neither anomaly impacted the mission. Further, the crew was briefed on flight software, guidance, navigation and control (IGNC), hydraulics (HYD)/ auxiliary power unit (APU), and instrumentation as ready to support. A manipulator positioning mechanism (MPM) stow switch rigging condition was mentioned in the briefing that required a minor procedural workaround for stowing the remote manipulator system (RMS), but had no mission impact. The main propulsion system (MPS) and Space Shuttle main engine (SSME) systems were briefed as nominal. The crew was briefed on an intermittent left RCS crossfeed 3/4/5 talkback, and valve operation was confirmed to be nominal. The right OMS regulator B locked up at the secondary regulator pressure, indicating the failure of the primary regulator. The crew was briefed to close the B regulators after main engine cutoff (MECO) for the remainder of the flight and to use the A regulators. The OMS and RCS propellant loads were confirmed to be as planned before the mission. Specifically, they were 83 percent left and right, with 80 percent loaded in the forward RCS and 100 percent in the aft RCS. The crew was also briefed on the thermal protection system, which was ready for flight. Because of weather exposure at pad B (i.e., the rain protection....
[J20] ....curtains available at pad A were not yet installed at pad B), areas of the lower surface waterproofing had degraded and a second coating of Scotchgard had been applied to the lower surfaces of all four elevons and portions of the lower wing surfaces aft of the main landing gear doors. All parties at the crew's L-1 briefing indicated they were ready for launch and had no issues that would be an impact to the mission.
8. Planned Mission Timeline Summary
STS 51-L was planned for a duration of 6 day, with the I US/TDRS deployed on day 1, the SPARTAN deployed on day 3, and the SPARTAN retrieved on day 5. The STS 51-Lascent phase included an OMS-1 burn after MECO with a second OMS burn at 44 minutes mission elapsed time (MET) to insert the Orbiter into a 153.5 nautical mile high circular orbit in preparation for the IUS/TDRS deploy. After opening the payload bay doors (PLBD's) and configuring the Orbiter for on-orbit operations, the "GO" for staying on orbit was scheduled for approximately 1:40 MET. The remainder of flight day (FD) I consisted of two periods of fairly high activity. The first was from approximately 2:50 MET until 3:45 MET, during which the early checkout activities were performed for the IUS/TDRS.
After a lunch break, an RMS checkout was to be conducted and the second high-activity period started. This second period ran from 7:40 MET until 11:45 MET and consisted of the final predeploy checkout activities for the IUS and the TDRS, the actual deployment, and the postdeployment separation maneuvers. The first sleep period was scheduled to be 8 hours long, starting at 13:15 MET.
Crew wakeup on FD 2 was scheduled at 21:15 MET. Flight day 2 was the backup TDRS deploy clay and, depending on the date of the launch, the CHAMP data takes were scheduled to begin on this day (i.e., after January 28, 1986, the comet and sunset times were too close to be able to perform the CHAMP activities). Also scheduled on FD 2 was the initial teacher in space videotaping and a recircularization burn to return the Orbiter to a 152 nautical mile circular orbit in preparation for the SPARTAN-Halley deploy on FD 3. (The orbit had been made slightly elliptical as a result of the FD 1 separation maneuvers following the IUS/TDRS deploy.)
Flight day 3 consisted of the crew programming the SPARTAN-Halley satellite with data prepared and uplinked to them by the flight controllers in Houston, then the SPARTAN deployment was followed by the separation maneuver away from the SPARTAN by the Orbiter. The separation maneuver set up the Orbiter to drift for 16 revolutions until, at around 90 miles behind the SPARTAN on FD 4, the nominal correction 1 (NC 1) burn, which is a phasing maneuver, was to be performed to start the Orbiter closing with the SPARTAN again. The FD 4 activities, in addition to the NC1 burn done late in the day, consisted of continuing the fluid dynamics experiment started on FD's 2 and 3 on the middeck and of delivering the two live TV lessons by the teacher in space.
After drifting back in toward the SPARTAN for 10 revolutions, the second rendezvous burn, NC2, was scheduled on the morning of FD 5. Two revolutions after NC2, another bum called "TI" (Terminal Phase Initiation) was planned to initiate the terminal phase of the rendezvous and to allow the Orbiter to be flown back to the SPARTAN in order to capture it with the remote manipulator system (RMS) and restow it in the payload bay.
Flight day 6 was dedicated to performing the flight control system (FCS) checkout in preparation for entry day. to perform the RCS hot fire test which exercises all the high priority RCS jets needed for entry that were not used on orbit, and to spend the afternoon performing cabin stowage. A crew news conference also was scheduled, if requested by the Public Affairs Office, just following the lunch period.
Flight day 7 was scheduled to start with crew wakeup at 5 days, 16:30 MET, with the crew starting their deorbit preparations checklist at 5 days, 19:37 MET. This activity included loading the entry flight software, closing the PLBD's, loading the deorbit burn targets, and configuring the Orbiter's controls to fly the reentry. The deorbit burn was scheduled for 5 days, 23:37 MET, and would have resulted in a landing on the 97th orbit at KSC at 6 days and 34 minutes MET on KSC runway 33. An overview of, the projected timeline for the mission is shown in figure 7.
Several backup timelines were developed before the mission that could be used in the event of various anomalies. The first set covered insertion into a less than nominal orbit, such as an abort-to-orbit (ATO) (105 by 105 nautical miles). The recovery plans provided for the most efficient use of the propellant remaining onboard to raise the orbit for the TDRS deploy as high as possible and still have sufficient fuel to recircularize the orbit for SPARTAN deploy, separation, and rendezvous, with a subsequent deorbit to KSC.
Backup timelines for late deploys for the TDRS were published in the CAP, assuming the nominal deploy for a revolution 8 IUS burn was not performed. Deploy opportunities that were 1 and 2 revolutions late were published and carried onboard, as was the timeline for an FD 2 deploy for a revolution 18 IUS burn if all FD 1 attempts were not performed.
The SPARTAN deploy on FD 3 had both a 1 and a 2 revolution late timeline developed but, since the activities were more straightforward, only the nominal was onboard. All that would have been required for the late SPARTAN deploy was to voice up some new programming codes and new deploy times. The rendezvous would have changed for late deploys, but only insofar as when the NCI burn occurred, so the rendezvous would have remained at the same MET (i.e., the late deploy would have shortened the SPARTAN's free-flyer mission time).
Deorbit and landing opportunities at KSC were planned for the nominal +1 and nominal +2 day timeframes in the event weather or systems problems prevented deorbit at the nominal end of mission. One revolution late deorbit opportunities at EAFB were planned as backups to all KSC opportunities.
In case the Orbiter encountered a failure that reduced redundancy in an entry system, a priority flight was planned to perform only the high-priority on-orbit activities and come home early. The TDRS deploy and backup opportunity were on FD's 1 and 2, with SPARTAN deploy on FD 3 and SPARTAN retrieve on FD 5. Deorbit was tentatively planned on FD 6. The ground -rules for determining priority flight and for late deploys and ATO recovery actions were all documented in the flight-specific Flight Rules Annex. The crew carried the CAP onboard with all the backup TDRS deploy timelines in it, and the ground also had available the Operations Support Timeline (OST), which had greatly expanded ground support scheduled activities for all the TDRS primary and backup deploy activities.
9. Findings
a. Changes to the payload manifest required launch slips from the initial early July 1985 date to the final date in January 1986. After the CIR, the primary payload manifest was very stable. However, several changes to the secondary manifest occurred after the L-5 freeze point. With the exception of the addition of the PS's the crew assignment was never changed.