AAS 95-315 Dactyl Orbit Determination Analysis D. V. Byrnes and L. A. D'Amario, Jet Propulsion Laboratory, Pasadena, CA Abstract Galileo's recent discovery that the asteroid Ida has a satellite (now known as Dactyl) has allowed, for the first time, an accurate estimate of an asteroid's bulk density. Dactyl and Ida appear in 47 image returned from the Ida encounter. The locations of Ida and Dactyl in these images were used to estimate Dactyl's orbit as a function of Ida's mass. Interestingly, a wide range of possible orbits fit the observational data equally well, so dynamical and statistical arguments are necessary to constrain the range of possible orbits and hence the mass of Ida.