Report of the PRESIDENTIAL COMMISSION
on the Space Shuttle Challenger Accident
[225-256] Appendix D: Supporting Charts and Documents Referred to
During The Commission Investigation and Report
Table of Contents
1. Relevant Organization Charts of NASA and
2. Temperature Definitions (as applicable to
Field Joint (O-ring)
A calculated temperature for the
surface of the Solid Rocket Booster in the vicinity of the
tang/clevis joint. The O-ring temperature is assumed to be
the same. Calculations are based on a thermal model which
includes ambient temperature among the variables. (See
references 1 and 2.)
Ambient Temperature (at
Measured atmospheric temperature at:
(See reference 3)
- Camera Site 3, approximately
1,000 feet, bearing 150 degrees from Launch Pad 39B (36
degrees Fahrenheit at launch.)
- At a weather observation site
approximately 3,000 feet east of the Kennedy Shuttle
Landing Facility; (reported minimum of 24 degrees
Fahrenheit and maximum of 43 degrees Fahrenheit for
January 28, 1986).
- 1. Report, "Accident Analysis
Team Report, Solid Rocket Motor Working Group, NASA, April 1986",
pages B-105 through B-114.
- 2. Commission Panel Work Session
(Solid Rocket Booster matters) Design and Production Panel;
Brigham City, Utah, March 18, 1986, pages 392 through 403.
- 3. Report, "Accident Analysis
Team Report, Space Shuttle Systems Working Group. NASA, April
1986", pages 18 through 23, Tables B.1 and B.2.
Note: A comparison of atmospheric
environmental data (wind, temperature, precipitation) for Flights
STS-1 through STS-61C in included in Tables B.5 and B.6 of reference
3. Early Marshall documents and memoranda
raising design objections.
- This briefing chart is the earliest known indication that the joint
design was unacceptable. Leon Ray, in a 1977 briefing on a planned
Structural Test Article test indicates that no changing the design
is unacceptable since the tang can move outboard and cause
excessive joint clearance resulting in seal leakage.
- This memorandum, written by Leon Ray and signed by John Q. Miller,
strongly urged that the clevis joint be redesigned.
- This memorandum, also written by Leon Ray and signed by John Q.
Miller, strongly questions the clevis joint design. It is the
earliest known official document which questions the redundancy of
- This Leon Ray
memorandum documents his visits to two O-ring manufacturers,
both of whom expressed concern relative to the O-ring performing
properly in the joint design.
4. Documents relating to the change from
Criticality 1R to 1, and the waiver of the redundancy requirements
for the Solid Rocket Motor seal.
- This original Critical Items List
entry for the Solid Rocket Motor
case joint seals establishes them as Critically 1R
- In late 1982, Marshall
Safety, Reliability and Quality Assurance engineers reviewed test
and analysis results and determined that the case joints should be
reclassified as Critically 1 (not redundant). This form was signed by Maurice (Bud) Parker, a local Thiokol
Reliability engineer, beginning the process of management approval
of the Criticality change.
- On January 21, 1983, the
Marshall Configuration Control Board, chaired by Lawrence Mulloy,
change from Criticality 1R to
Criticality 1 and approved it for forwarding to Level II.
- After receiving written
concurrence from certain Johnson organizations, Glynn Lunney, the
Shuttle Program Manager, approved the Criticality change, based on
a telephone conversation with Lawrence Mulloy, the Solid Rocket
Booster Project Manager. The action was taken without convening a
meeting of the Program Requirements Control Board. This action
authorized submittal of a waiver of the "fail-safe" design
requirement to Level I.
Glynn Lunney signed this request for Level I to approve for the field joint a waiver
of the "fail-safe requirement" for Shuttle component, in that the
joint had been reclassified as Criticality 1 (no redundancy). The
waiver was approved for Level I by L. Michael Weeks on March 28,
5. Memoranda written following the field joint
O-ring erosion on STS 41-B (flight 10).
- This internal Marshall
note was written by John W. Miller after the O-ring
erosion experience on STS 41-B (flight 10), indicating concern
that the leak check procedures may displace putty ("blow-holes")
leading to O-ring burning ("erosion"). STS 41-B was the first
flight for which a 200 psi leak check stabilization pressure was
- In this memorandum to Lawrence Mulloy, George Morefield compares the
Titan joint with the Shuttle joint and assesses a higher failure
probability for the shuttle joint, indicating concern that putty
may cause "single point pressurization" of the primary
6. Marshall urgent request for briefing after
the STS 51-C mission (flight 15).
- Following the discovery
of the STS 51-C (flight 15) O-ring erosion and blow-by, Lawrence
Mulloy sent this "Certified Urgent"
message to the Solid Rocket Motor
manager, Larry Wear. This message was passed on to Thiokol as
direction to prepare a detailed briefing on O-ring problems for
the next Flight Readiness Review.
7. Internal NASA Headquarters memorandum after
visit to Marshall.
- This memorandum to Level I describes a visit to Marshall by Irving
Davids of NASA Headquarters. Davids' visit was prompted by the
nozzle O-ring problems suffered on STS 51-B (flight 17).
8. Thiokol letters and memoranda written after
O-ring concern escalates.
- Roger Boisjoily's
attempt after STS 51-B (flight 17)
to convince his management of the seriousness of the O-ring
- In this memorandum to S.R. Stein, A.R. Thompson indicates the O-ring
seal problem is acute and short-term measures should be taken to
reduce flight risk.
- In this weekly activity
report, Robert Ebeling attempts
("Help!") to draw management attention to the difficulties
experienced by the seal task force in getting adequate support,
indicating "This is a red flag."
- S.R. Stein echoes the
concerns about the seal task force
not getting full support.
- In this activity report, Roger Boisjoly expresses his frustration with the
slow progress of and lack of management attention to the seal task
9. Marshall internal memorandum in the fall of
- In this memorandum, J. E. Kingsbury informs Lawrence Mulloy that he
places high priority on the O-ring seal problem and desires
additional information on plans for improving the