COST ESTIMATION AND MODELING FOR SPACE MISSIONS AT APL JHU/

Cost estimation of space science missions at APL over the past two dec ades has been singularly successful in arriving at program costs that are within a few percent of the actual costs at program completion. Th e most recent example is the Near Earth Asteroid Rendezvous (NEAR) mis sion which was estimated at approximately 112 million FY-92 dollars an d came in at approximately three percent under the estimated cost. Thi s demonstrated performance has been achieved without the benefit of a formal cost model, such as those used in government and industry (GSFC , MSFC, SAIC, etc.). In light of this performance, it is important to understand the parameters that ate used in the cost estimating process in an effort to quantify those elements in a program that are most im portant to the final cost. We have identified a number of areas which contribute to eventual cost performance; these include: (a) spacecraft and mission complexity; (b) use of already-developed (facility-class) instruments versus ''to be developed'' new instruments; (c) synergism among programs being implemented concurrently; (d) program implementa tion length; (e) design-to-cost practice for all major subsystems and instruments without contingency; (f) lead engineer responsibility thro ughout design, layout, fabrication, test, integration, and initial fli ght operations; (g) designed-in quality and testability to minimize re work; (h) incorporation of reliability and quality assurance engineeri ng within the program structure; (i) minimization of documentation and encouragement of oral and electronic communication as required. We ha ve found that gross parametrization of costs such as the traditional w eight, power, and length of the program commonly included in typical m odels do not reliably predict actual costs. A methodology will be pres ented, whereby, the elements identified above plus others are used to describe the process implemented by APL in previous missions to genera te cost estimates and to control costs. Actual data over several missi ons during the past two decades will also be presented that illustrate APL's cost performance while utilizing this methodology. Copyright (C ) 1997 Elsevier Science Ltd.