REG NASA-LLIS-3099-2010 Lessons Learned - Dome Heat Shield Alignment Tool.pdf

1、 Public Lessons Learned Entry: 3099Lesson Info:a71 Lesson Number: 3099a71 Lesson Date: 2010-05-17a71 Submitting Organization: KSCa71 Submitted by: Annette PittSubject: Dome Heat Shield Alignment Tool Abstract: A simple tool consisting of a tapered bolt, a nut, and two close-tolerance “hat“ bushings

2、can be used to align two holes, without the use of undesired force.Description of Driving Event: On multiple occasions when close-tolerance attachment holes did not align during installation of the Orbiter dome heat shield, workers manually applied an unknown amount of force to the lifting fixture u

3、ntil the holes aligned, allowing the mounting bolts to be installed. The lifting fixture was damaged on more than one occasion.Lesson(s) Learned: A simple shop aid can align holes, without the application of force to the lifting fixture. The Dome Heat Shield Alignment Tool consists of a hardened-ste

4、el bolt with a 5-degree tapered shank, two close-tolerance brass “hat“ bushings (one for the hole in the Orbiter base heat shield and the other for the hole in the dome heat shield), and a steel hex nut (free of all locking features). As the nut is turned, one of the bushings rides up the taper on t

5、he bolt, and the holes align. Fasteners are then installed in the holes adjacent to (i.e., above and below) the hole with the tool. When the tool is removed, the center hole remains aligned. A running torque restriction limits the forces. The tool has been used with great success on all the Orbiters

6、. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Dome Heat Shield Alignment Tool used for alignment of holesRecommendation(s): Two holes can be aligned with a tapered, hardened-steel bolt, two close-tolerance brass “hat“ bushings, and a steel hex nu

7、t (free of all locking features), as long as the running torque is kept to a reasonable limit.Evidence of Recurrence Control Effectiveness: The tool was used with great success on all the Orbiters.Documents Related to Lesson: N/AMission Directorate(s): a71 Space OperationsAdditional Key Phrase(s): a

8、71 1.Ground support systemsa71 0.Spacecraft and Spacecraft InstrumentsAdditional Info: a71 Project: Space Shuttle ProgramApproval Info: a71 Approval Date: 2010-08-26a71 Approval Name: mbella71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-