ISS-VIEW: A software pool for external science payloads attached to the international space station

In the framework of the Agreement for the Early Utilisation of the International Space Station (ISS), ESA has negotiated with NASA to have early flight opportunities for European payload instruments prior to the launch of the Columbus Orbital Facility, in exchange for the delivery to NASA of a set of items that constitute the early European contributions for the utilisation of the International Space Station. One of these early European contributions is the Hexapod positioning/pointing system, which is being developed under the responsibility of ESA's Directorate of Manned Spaceflight and Microgravity to provide a pointing platform for the NASA Stratospheric Aerosol and Gas Experiment III (SAGE III) instrument. Hexapod and SAGE III are designed to be accommodated on an ISS Express Pallet and have a five-year design lifetime. They will be launched with Space Shuttle flight UF-4 at the beginning 2002. The ISS-VIEW software tool has been developed to support the mission analysis and to define the observational windows for Hexapod/SAGE III, but it can also be used for other instruments. for example, it also allows one to predict astronomical or Earth-target observing opportunities for Express Pallet payload instruments from their actual mounting locations on the Space Station Truss. In addition to the orbital and attitude parameters of the Station, ISS-VIEW is also able to take into account the field-of-view restrictions imposed by both the fixed and movable elements of the overall Space Station assembly.