Summary of Launch Operations

¶Issue 1

¶How was the decision to launch STS 51-L arrived at and why was it wrong?

¶Findings

¶1. The Flight Readiness Review for STS 51-L was conducted in accordance with established procedure.

¶2. The decision to launch STS 51-L was based on a faulty engineering analysis of the SRM field joint seal behavior.

¶3. Compounding this erroneous analysis were serious ongoing weaknesses in the Shuttle Safety, Reliability and Quality Assurance Program which had failed to exercise control over the problem tracking systems, had not critiqued the engineering analysis advanced as an explanation of the SRM seal problem, and did not provide the independent perspective required by senior NASA managers at Flight Readiness Reviews.

¶4. The initial response of Marshall managers to the attempts of Thiokol engineers to raise the issue of temperature effects on the SRM seals caused Thiokol management to discount proper technical concerns and engineering judgment in their recommendation to launch.

¶5. The Director of Marshall's Shuttle Projects Office may have violated NASA's Flight Readiness Review policy directive by failing to report the results of the January 27th teleconference to the Associate Administrator for Space Flight.

¶6. The decision of the STS Program Manager to launch despite the uncertainty represented by ice on the Fixed Service Structure was not a prudent effort to mitigate avoidable risks to the Shuttle.

¶7. The Launch Director failed to place safety paramount in evaluating the launch readiness of STS 51-L. 8. No launch should have been permitted until ice was cleared from the platform leading to the pad escape system.

¶9. Ice Team personnel and Rockwell contractors properly conveyed their inability to predict the post-ignition behavior of ice.

¶10. Post-flight analysis indicates that ice did not exhibit the behavior predicted by analysis, and that ice traversed a distance sufficient to strike the Shuttle during liftoff.

¶11. Failure to enforce a clear requirement for definite readiness statements contributed to failures in communication between NASA and its contractors during launch preparations.

¶Issue 2

¶Should firing room personnel be allowed to waive launch commit criteria or equipment redlines during a launch countdown without a well-developed technical reason for doing so?

¶Finding

¶NASA's management waived its own launch commit criteria on January 28, 1986, without a valid technical reason for doing so.

Retrieval, Transportation and Refurbishment

¶Issue

¶Were the motor casings used on STS 51-L damaged as a result of the retrieval, transportation and refurbishment operations following previous launches?

¶Finding

¶There was no evidence of damage to the casings or joint due to prior use or preparation for reuse.

EXTERNAL TANK

Issue

¶The External Tank was obviously involved in the accident. Was that involvement a cause or an effect?

Findings

¶1. The Committee adopts the "Finding" of the Rogers Commission that: "A review of the External Tank's construction records, acceptance testing, prelaunch and flight data and recovered hardware, does not support anything relating to the External Tank which caused or contributed to the cause of the accident."

¶2. The External Tank ruptured under the forces of a failed Solid Rocket Booster motor. These forces were far outside of any possible design considerations that could have been applied to the External Tank.

CREW SURVIVAL

Issue

¶Was the accident of STS 51-L on January 28, 1986, survivable? Finding

¶In the case of the tragic loss of the Space Shuttle Challenger and her crew on January 28, 1986, the Committee is convinced that the accident was not survivable.

SABOTAGE

Issue

¶Could the accident have been caused by sabotage, terrorism, or foreign covert action?

Finding

¶The Committee is convinced that there is no evidence to support sabotage, terrorism or foreign covert action in the loss of the Challenger.

ADDITIONAL AVENUES OF INVESTIGATION

Issue

¶Could the accident have been caused by some failure other than failure of the joint between the casings?

Finding

¶As of September 15, 1986, the Committee has not found any credible evidence to support any caiise of the Challenger accident, other than the failure of the aft casings joint in the right-hand Solid Rocket Booster. Nor has there been any substantial evidence of a secondary or parallel failure on Flight 51-L.

Summary of Launch Operations