INTRODUCTION

¶This section as well as Sections VII and VIII identify what happened, as well as what did not happen, to cause the loss of the Challenger. This section also discusses why the accident happened in a n effort to prevent future catastrophes.

¶By the time the Rogers Commission had completed its report, it had been learned that many items investigated by the Commission did not contribute to the accident. Consequently, this section is directed toward a more narrow range of possible contributing causes.

¶There were human as well as technical failings that combined on the morning of January 28, 1986, to cause the Challenger accident. Most of NASA's personnel were not involved in the Solid Rocket Motor program while there were others outside of NASA, such as the media, the Congress and the Administration, who were involved through their influence on the Shuttle program.

¶It should also be recognized that this report has the advantage of hindsight. Our investigation indicates that the decision to launch Challenger on January 28 suffered equally from a lack of information, misinterpretation of the information that was available, and a complex interplay of personalities among the principals involved. We are equally convinced, however, that the resulting decision to launch was arrived at as a logical conclusion of faulty premises, coupled with a failure to recognize the effect of temperature on the design.

¶We hope the lessons learned from this accident will lead to design improvements in the Shuttle Program. Just a few years ago, the collapse of the Hartford Civic Center contributed to the improvement of engineering design techniques to accommodate the unique secondary forces inherent in long-span structures. The Gothic cathedrals of the fourteenth century were constantly improved after their early failures were studied.

¶We hope this section, as well as Sections VII and VIII, properly identify the mistakes that led to the Challenger accident. It is the intent of the Committee to identify these mistakes so that NASA will regain its former level of excellence. The Committee has confidence that the men and women of the Natiooal Aeronautics and Space Administration will meet the challenge, improve the Shuttle and their management methods, and go on to explore new frontiers in space. This assumes, however, that the agency will now receive resources adequate to support the programs it is authorized to carry out by the Congress and the President.

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¶For the benefit of those who may not be familiar with the Space Transportation System, the Shuttle consists of a n Orbiter (51-L's Orbiter, the Challenger, was one of a four-vehicle fleet), a n External Tank (ET),and two Solid Rocket Boosters (SRBs). (See Figure V-1.) A brief description of the Solid Rocket Booster and the Solid Rocket Motors is included to familiarize readers with these systems.

EXTERNAL TANK

/ -t/ ..::

LEFT'SOLID ROCKET BOOSTER I

¶L

¶TER

¶V-1

¶The Solid Rocket Boosters operate in parallel with the main engines for the first two minutes of flight to provide the additional thrust needed if the Orbiter is to escape the gravitational pull of the Earth. At an altitude of approximately 144,000 feet (24 nautical miles), the SRBs separate from the Orbiter/External Tank, descend on parachutes, and land in the Atlantic Ocean. They are recovered by ships, returned to land, and refurbished for reuse.

¶The heart of the booster is the Solid Rocket Motor (Figure V-2). It is the largest solid propellant motor ever developed for space flight and the first built to be used on a manned craft. Larger solid motors have been test-fired but have never been carried through complete development to actual use in flight. The huge Solid Rocket Motor is composed of a segmented motor case loaded with solid propellant, an ignition system, a movable nozzle, and the necessary instrumentation and integration hardware.

STATISTICS FOR EACH BOOSTER FRUSTRUM

¶THRUST AT LIFT-OFF (2,650,000 pounds)