Title

A Probabilistic Tool That Aids Logistics Engineers In The Establishment Of High Confidence Repair Need-Dates At The Nasa Shuttle Logistics Depot

Abstract

The NASA Shuttle Logistics Depot (NSLD) is tasked with the responsibility for repair and manufacture of Line Replaceable Unit (LRU) hardware and components to support the Space Shuttle Orbiter. Due to shrinking budgets, cost effective repair of LRUs becomes a primary objective. To achieve this objective, it is imperative that resources can be assigned to those LRUs which have the greatest expectation of being needed as a spare. Forecasting the times at which spares are needed requires consideration of many significant factors including, for example, failure rate, flight rate, spares availability, and desired level of support, among others. This paper summarizes the results of the research and development work that has been accomplished in producing an automated tool that assists in the assignment of effective repair start-times for LRUs at the NSLD. This system, called the Repair Start- time Assignment System (RSAS), uses probabilistic modeling technology to calculate a need date for a repair that considers the current repair pipeline status, as well as, serviceable spares and projections of future demands. The output from the system is a date for beginning the repair that has significantly greater confidence (in the sense that a desired probability of support is ensured) than times produced using other techniques. Since an important output of RSAS is the longest repair turn-around time that will ensure a desired probability of support, RSAS has the potential for being applied to operations at any repair depot where spares are on-hand and repair start-times are of interest. In addition, RSAS incorporates tenants of Just-In-Time (JIT) techniques in the connotation that the latest repair start-time (i.e., the latest time at which repair resources must be committed) may be calculated for every failed unit. This could aid in reducing the spares inventory for certain items, without significantly increasing the risk of unsatisfied demand.

Publication Date

1-1-1995

Publication Title

Space Logistics Symposium

Number of Pages

46-53

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.2514/6.1995-910

Socpus ID

84983200631 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84983200631

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