Calibration of the wide angle camera for the Rosetta mission: Preliminary results on the flight model

Rosetta is one of the cornerstone missions of the European Space Agency for having a roundez-vous with the periodic comet P/Wirtanen in 2011. One of the imaging instruments on board the satellite is the Wide Angle Camera, a cooperation among several european institutes. This camera adopts an all reflecting, unvignetted unobstructed two mirror configuration which allows to cover a 12° × 12° Field of View with an F/5.6 aperture and an optical quality better than 80% geometrical ensquared energy inside approximately 20 arcsec. The flight model of this camera has been successfully integrated and tested in our laboratories and finally has been integrated on the satellite. In this paper we are going to describe the optical characteristics of the camera, and to summarize the results so far obtained with the preliminary calibration data. The analysis of the optical performance of this model shows a good agreement between theoretical performance and experimental results.