The Requirements Development and Validation (RDAV) is a program that allows engineers and other technical specialists to perform requirements management and cost estimation tasks with rigorous traceability. The RDAV systems engineering tool set was originally developed to fill a specific need at the Air Force Space and Missile Systems Center (SMC) to replace commercial systems requirements analysis (SRA) tools in use at SMC that did not satisfy government needs for a low-cost, non-proprietary, easy to use, tool for SRA. RDAV was developed by bd Systems and has been applied to several large space systems development programs, most recently the GPS program.