The Crosstrack Infrared Sounder (CrIS) is one of the sensors now under development for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) program. In order to reduce program risk and verify instrument performance rapid prototyping of the sensor and critical subsystems has been utilized. Key among these was a prototype instrument and a prototype interferometer. This prototype instrument is referred to as the EDU1 (Engineering Development Unit). A second effort was the build of a prototype interferometer as a part of an internal ITT effort. This was an uncompensated version of the CrIS interferometer. This was referred to as the Aluminum Prototype Interferometer. The idea was to move rapidly to hardware while exploring new technologies. This was built in 4 months. There were key success factors for both efforts. A set of clear cardinal requirements was established. The layout and the cardinal requirements therefore provided a conceptual overview and a basis for deriving lower level requirements. These requirements remained basically unchanged throughout the effort. Vendors were closely worked with but; key to this was the GD&T dimensions and datum’s that were established. These enabled sub systems to be independently produced and “snapped together” to produce a final assembly in a minimum time. Essentially many of the critical optical alignments were built in to the individual parts so the subsequent shiming was not required. Electronics to control the porchswing and Dynamic Alignment Mechanism were developed in existing servo control test beds and designed to be FPGA based. This allowed a high degree of flexibility. Success was also based on continuity of the key engineering leadership and effective communications between the team and a clear understanding of the technical issues by the engineering leadership team.
The Crosstrack Infrared Sounder (CrIS) is one of the sensors now under development for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) program. In order to reduce program risk and verify instrument performance on the CrIS Program, various independent research projects were integrated into a prototype instrument. This was a rapid prototype built in 6 months that was similar to flight in the significant risk areas. This prototype instrument is referred to as the EDU1 (Engineering Development Unit). The coordination between the various, previously disjointed research tasks was a critical part of the effort. A layout of the flight CrIS instrument was the departure point for this effort. This layout was used to establish interfaces between the various modules. A set of clear cardinal requirements was established. The layout and the cardinal requirements therefore provided a conceptual overview and a basis for deriving lower level requirements. These requirements remained basically unchanged throughout the effort. The purpose of this paper is to describe the CrIS EDU1 system design and build, and summarize the key performance capabilities of the EDU1.
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