1、Lessons Learned Entry: 0198Lesson Info:a71 Lesson Number: 0198a71 Lesson Date: 1992-11-04a71 Submitting Organization: KSCa71 Submitted by: Lisa L. MusgraveSubject: Launch Complex Systems Performance Description of Driving Event: The effects of an adverse environmental condition, specifically, unusua
2、lly cold weather, are not sufficiently well understood. The amount of ice formed by leaving valves open to prevent freezing inside water pipes was greater than expected. After the STS 51-L launch, photographic documentation revealed that ice released from the pad structures after engine ignition tra
3、nslated further toward the vehicle than predicted. The performance of some complex 39B systems was marginal due to the cold. The number of cameras that failed to operate at liftoff was three times that of the historical average. Instrumentation and analytical models were not adequate to define the u
4、nusually cold operating environment in which the launch was conducted. Additionally, the effects of such temperatures on the components of a space shuttle standing on the pad have not been sufficiently determined.Lesson(s) Learned: Without full assessment of capability of vehicle and facility to wit
5、hstand adverse environmental conditions, a potential for unexpected problems exists.Recommendation(s): Reassess/improve the effects of adverse environmental conditions on pad systems and impose appropriate launch constraints.Evidence of Recurrence Control Effectiveness: N/AProvided by IHSNot for Res
6、aleNo reproduction or networking permitted without license from IHS-,-,-Documents Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 EnvironmentAdditional Info: Approval Info: a71 Approval Date: 1994-06-06a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
