MISSION DESIGN FOR AN ORBITING VOLCANO OBSERVATORY

The Mission to Planet Earth initiative will require global observation of land, sea, and atmosphere and all associated phenomena over the coming years, perhaps for decades. A major phenomenon playing a major part in Earth's environment is volcanic activity. Orbital observations, including IR, uv, and visible imaging, may be made to monitor many active sites, and eventually increase our understanding of volcanoes and lead to the predictability of eruptions. This paper presents the orbital design and maneuvering capability of a low cost, volcano-observing satellite, flying in low Earth orbit. Major scientific requirements include observing as many as 10-20 active sites, either daily or every 2 or 3 days. Given specific geographic locations of these sites, it is necessary to search the trajectory space for those orbits that maximize overflight opportunities. Also, once the satellite is in orbit, it may be desirable to alter the orbit to fly over other targets of opportunity. These are active areas that are not being monitored, but which give indications of eruption, or have in fact erupted. Multiple impulse orbital maneuvering methods have been developed to minimize propellant usage for these orbital changes. Mission lifetime is assumed to be 2-3 years.