National Polar-orbiting Operational Environmental Satellite System (NPOESS) Spacecraft baseline design, progress and plans for insertion of "Instruments of Opportunity"

The NPOESS spacecraft design is based on the Northrop Grumman T430 that has legacy to EOS Aqua and Aura. This larger sized bus has been enhanced to support 14 or more sensors in common locations for the 3 NPOESS orbit planes. Spacecraft deck space and other spacecraft resources such as mass, power and data accommodation have been reserved for "Instruments of Opportunity\´\´ that may be selected and inserted into the baseline mission schedule at later dates. This presents a unique challenge to the Integration Contractor and the Program Office. However coping with this "unknown" can be minimized with forethought to the implications. Early on in the Program Definition and Risk Reduction phase of NPOESS a General Interface Design Document was created to set accommodation guidelines for current and future Payloads. It was also necessary to create a "resource document" and "insertion plan" in parallel with the spacecraft design effort. This paper will report on the progress of the spacecraft design and the special study task intended to facilitate both spacecraft and instrument needs now and into the future for successful satellite integration and the subsequent on-orbit mission.