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The Launch Operations Index (LOI)

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Disclaimer: This material is being kept online for historical purposes. The model, simulation or tool described is no longer maintained. It is no longer available on request, and/or may not function on current computer systems.



The Launch Operability Index (LOI) tool.


The LOI places custom Excel menu's at the top of the user interface (Insert, Options, Tools, File, LOI, etc). The user selects areas to evaluate, proceeds into a questionnaire characterizing each design feature, and receives a relative LOI score, an operability comparison, from 0 to 1.


The Launch Operations Index tool (LOI) used MS Excel in 1992 to calculate a measure of the relative operability of a proposed space system design. The LOI used a simple graphic user interface (GUI), representing the knowledge captured with a structured analytic hierarchy process (AHP). This combination of a GUI, AHP and MS Excel were both new for their time, influencing later models significantly. This thinking would eventually lead to later work in space systems operations research using Quality Function Deployment (QFD) methods.


The launch operability index's "score" is a calculation of the relative measure of the operability of a propulsion system. The better the score, the easier the ground operations processing would be for that proposed propulsion system design, technology or approach. The LOI was one product of the Operationally Efficient Propulsion System Study (OEPSS). OEPSS was initiated to capture knowledge from the Shuttle experience to benefit the operability of follow on systems. The operability of a future system is the sum of it's complexity, maintainability and reliability, a result of systems design choices. The LOI would help launch site personnel communicate lessons learned to designers, developers and future programs.


Website Contact: Edgar Zapata, NASA Kennedy Space Center