1、Lessons Learned Entry: 1101Lesson Info:a71 Lesson Number: 1101a71 Lesson Date: 2001-01-01a71 Submitting Organization: JSCa71 Submitted by: Jeff Dutton / Ronald MontagueSubject: Hardware losses during STS-88 Extravehicular Activities (EVAs, also known as space walks) Description of Driving Event: Sev
2、eral items of EVA hardware were lost during the EVAs on STS-88. Impact to immediate mission is loss of availability of needed tools. Lost tooling, when unretrieved, also adds to on orbit debris.a71 The flight support equipment (FSE) for the EVA installable slidewire and an on-orbit installed worksit
3、e interface (OIWIF) with an attached retractable tether were lost on EVA1.a71 One of the trunnion pin covers was lost on EVA2.a71 Two of the safety tether hook guards were also lost during the EVAs.There is no identified common hardware cause for the lost hardware. The EVA Project Office chartered a
4、 team to investigate the issue and make recommendations for corrective action.Root cause:a71 Slidewire Carrier - inconclusive, most probable cause is inadvertent opening of Tool Stanchion bayonet.a71 On orbit installed WIF/retractable tether - inconclusive, most probable cause was the hardware was t
5、ethered to another end item and was released when that end item was removed from the mini workstation.a71 Trunnion pin cover - was not properly tethered due to a lack of a tether loop on the mockup/trainer.a71 Tether hook clips - inadequate restraint in design.Lesson(s) Learned: Careful planning fro
6、m design through training, flight rules, and operations is required to prevent loss Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-of equipment and tooling during space walk operations.Recommendation(s): Slidewire carrier - implement an operational
7、constraint to require that items in Tool stanchion and other similar bayonets also be tethered. OIWIF/retractable tether - reemphasize crew training to visually verify hook mate/demate on mini workstation. Trunnion pin cover - update trainer to include tether loop. Tether hook clips - Include integr
8、al ring/spring to allow clip to be attached back to itself.Evidence of Recurrence Control Effectiveness: All the recommendations were implemented for 2A.1 with no recurrence of loss.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Space Operationsa71 Aeronautics Res
9、earchAdditional Key Phrase(s): a71 Extra-Vehicular Activitya71 Flight Equipmenta71 Hardwarea71 Human Factorsa71 Policy & Planninga71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Spacecrafta71 Training EquipmentAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2002-02-12a71 Approval Name: Ronald Montaguea71 Approval Organization: JSCa71 Approval Phone Number: (281) 483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
