Abstract
Spacecraft is one of the largest and most complex systems of artificial products so that it necessitates application of systems engineering methods in its development process. Spacecraft development has a special difficulty because of its operations in low gravity and high vacuum environment, which makes system level tests impossible on the earth before launch. For this reason, it is common that design and manufacture are complementarily verified only by analysis. However, insufficient verification often results in on-orbit nonconformance, leading to unexpected anomalies in mission operations. This study is to propose to use Dual Vee Model developed in the recent advancement of strategic systems engineering methodology for identifying the root cause of such anomalies. Usefulness of this approach has been demonstrated by a real case of the communication interference, called multi-path, experienced on the Advanced Earth Observing Satellite-II (ADEOS-II) spacecraft. The Dual Vee Model consisting of the Architecture Vee and the Entity Vee turns out helpful to express the configuration items and the development sequence and to identify the process which could have caused the anomaly.
