Unique integration and test philosophy for the Wide-field Infrared Survey Explorer flight system

The WISE observatory contains solid hydrogen to achieve cooling, which precludes many of the "test as you fly" (TAYF) methods for the integration and test of the WISE flight system due to the hazardous nature of the solid hydrogen. Additionally, there is reluctance to remove the optical cover after integration to the spacecraft due to increased risk. This paper discusses the WISE approach to verification and validation (V&V) given these constraints. As payloads increase in size and complexity more missions will necessarily deviate from the TAYF approach. The WISE system combines full testing of the instrument while the fight system uses an interment simulator for many of the flight system environmental tests. The test planning, simulator design, and the analyses which indicate why this would be a low-risk V&V approach for the WISE mission are discussed.