1、Lessons Learned Entry: 1029Lesson Info:a71 Lesson Number: 1029a71 Lesson Date: 1997-02-01a71 Submitting Organization: HQa71 Submitted by: David M. LengyelSubject: Space Shuttle Program/Ground Processing Operations/Environmental Requirements and Obsolescence Issues Description of Driving Event: Mater
2、ials Obsolescence, Parts Obsolescence and Environmental Regulations Issues Cause Disruptions in Stable Shuttle Ground Operations ProcessesLesson(s) Learned: The Space Shuttle program has experienced some difficulties when stable work processes were altered to counter obsolescence or meet new environ
3、mental requirements. The simultaneous change in pressure sensitive adhesive and cleaning wipe in the RSRMs to meet environmental regulations is one example.Recommendation(s): The Space Shuttle program should not alter long-established and stable processes without defining and completing an adequate
4、test program. If changes in stable and well-characterized safety-related hardware and processes are being driven by environmental requirements, NASA should consider seeking waivers of these requirements rather than altering a proven design.Evidence of Recurrence Control Effectiveness: The SSP has be
5、en and is committed to not altering long-established and stable processes without defining and completing an adequate test program. The program has long had requirements governing the recertification of hardware in the event of either a hardware design change and/or a process change(s) that affect f
6、orm, fit, function, safety, and/or reliability. However, the program has authorized a recent requirement change (reference PRCB Directive S071024DL) to provide a Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-program-level review of all hardware and
7、/or process changes whose certification is based solely on analysis. This requirement change necessitates a program assessment of the rationale for specifically defined changes whose recertification is based solely on an analysis, as opposed to those where the recertification is based on the perform
8、ance of an adequate test program. It is felt that compliance with this new requirement will assure that changes to long-established and stable process changes are only implemented with adequate and appropriate recertification.For any safety-related hardware or process change that is being driven by
9、environmental requirements, NASA includes in its initial assessments the appropriateness of seeking a waiver to the requirements that are causing the change. Where such an assessment substantiates the appropriateness of a waiver, then that waiver shall be sought. The SSP adopted a policy that balanc
10、es flight safety and environmental protection goals in SSP letter MS-96-071, dated September 16, 1996. The SSP manager specified: (1) obtain long-term waivers for materials essential to safe Space Shuttle operations where functionality cannot be verified; (2) obtain long-term waivers for materials w
11、here no replacements exist; and (3) continue to pursue identification and certification of replacement materials.Documents Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Aerospace Safety Advisory Panela71 Environmenta71 Ground O
12、perationsa71 Hazardous/Toxic Waste/Materialsa71 Parts Materials & Processesa71 Policy & Planninga71 Safety & Mission Assurancea71 SpacecraftAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2001-11-20a71 Approval Name: Bill Loewya71 Approval Organization: QSa71 Approval Phone Number: 202-358-0528Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
