  This work introduces a method that applies images of the extended bodies in
the solar system to spacecraft camera calibration. The extended bodies consist
of planets and moons that are well-modeled by triaxial ellipsoids. When imaged,
the triaxial ellipsoid projects to a conic section which is generally an
ellipse. This work combines the imaged ellipse with information on the
observer's target-relative state to achieve camera calibration from a single
imaged ellipsoid. As such, this work is the first to accomplish camera
calibration from a single, non-spherical imaged ellipsoid. The camera
calibration algorithm is applied to synthetic images of ellipsoids as well as
planetary images of Saturn's moons as captured by the Cassini spacecraft. From
a single image, the algorithm estimates the focal length and principal point of
Cassini's Narrow Angle Camera within 1.0 mm and 10 pixels, respectively. With
multiple images, the one standard deviation uncertainty in focal length and
principal point estimates reduce to 0.5 mm and 3.1 pixels, respectively. Though
created for spacecraft camera calibration in mind, this work also generalizes
to terrestrial camera calibration using any number of imaged ellipsoids.
