Quality function deployment applied to an ALS cryogenic tank

Abstract

In the face of increasing international competition, U.S. space programs of the 90s must result in systems with dramatically improved operability and reliability and dramatically reduced cost. Current systems engineering approaches appear inadequate for this challenge. Quality Function Deployment is a new, yet proven tool which advances systems engineering to meet the demands of the 1990's. Quality Function Deployment (QFD) is a systematic way of capturing the skills and experience of cross-functional teams in designs that reflect customers' desires. This philosophy emphasizes concurrent product and process design involving design engineers, manufacturing, launch operations and the customer early in the concept design phase. Translation and flowdown of customer requirements is accomplished through the use of a series of tiered matrices known as the of Quality. This paper describes a QFD activity specifically aimed at the Advanced Launch System (ALS) cryogenic tanks. This area was chosen because of its relatively well defined scope, and its significant impact on cost, operability, and other program objectives. The effort was organized by the ALS government program office and was supported by a multidisciplinary team of government and contractor personnel. The QFD process was accomplished through a software implementation of the House of Quality and the guidance of a facilitator. Three sessions have resulted in a fop level QFD matrix which This paper is decIared a work of the U.S. Government and is not subject to copyright protection in the United States. identified a manageable number of issues and approaches worthy of greater attention. It has also improved the communication between organizations and functional disciplines. U. S. space programs are faced with the same customer behavior that all U. S. industries are feeling, customers that demand high quality products which are dependable and low cost. The objective of the Advanced Launch System (ALS) is to provide a highly reliable and operable launch vehicle at a congressionally mandated $300/lb of payload into low earth orbit. ALS must also meet its launch goals of payload to space without costly delays. Gone are the days of money is no object. Current unmanned recurring launch vehicle costs are estimated at $3000/lb. ' This figure is a result of manufacturing and operation systems fraught with conflicting resource requirements, assembly problems, high scrap and rework, and cumbersome rules and regulations. In order to quantify the benefits of proposed ALS alternatives, we must first understand this business as usual baseline and use it as the measure of merit for all suggested improvements. The goal of the ALS is to provide an order of magnitude reduction in cost. To meet this goal may require a revolutionary change from the business-as-usual approach. This demand has led to the need for implementing a Total Quality Management (TQM) philosophy where higher quality products lead to a reduced life-cycle-cost. Quality, cost, timeliness, and productivity are often viewed as conflicting elements that require making tradeoffs. A new product development theory called Quality Function Deployment (QFD) has emerged to offer an optimum compromise between seemingly conflicting alternatives. QFD also identifies design characteristics that contribute most to customer requirements. The results of a QFD exercise can thus focus any cost benefit analysis between business as usualn designs and suggested improved designs. Quality Function Deployment has been successfully applied to product development here in the United States, usually on automotive and computer application^.^ Aerospace industry QFD case studies and efforts are just now beginning to appear in print. '.4s Furthermore, applying QFD to a launch vehicle subcomponent is not known to have been attempted. The ALS cryogenic tank was selected as a QFD case study because the airframe contributes most to the recurring cost of existing unmanned launch vehicles. This study focuses on the principles of QFD as applied to cryogenic propellant tank development for the Joint NASA-US Air Force ALS Program.