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D.J. Scheeres (Iowa State University), F. Marzari (University of Padova)
The motion of spacecraft and particles about comets, and natural ejecta launched from the comet surface are studied. The model used to study this system includes effects of the solar tide, solar radiation pressure, comet outgassing, nucleus gravity field, and nucleus rotation state. Analysis results include a stability diagram for spacecraft orbits, lifetime estimates for bodies ejected from the comet surface, and a description of the basic physics of orbit dynamics in the comet environment.
Large classes of motion exist which are unstable and lead to escape from or impact onto the nucleus in short time scales. However, some classes of motion exist that exhibit stability over long time periods, including cases that maintain orbital stability through perihelion passage. Such orbits would allow spacecraft to monitor the comet through perihelion. The existence of stable orbits also indicate that natural particles lifted from the comet surface may remain in orbit about the comet for extended periods of time, or at least until perihelion is encountered again.
The author(s) of this abstract have provided an email address for comments about the abstract: scheeres@iastate.edu