In-flight calibration of the osiris-rex optical navigation imagers

Navigation for solar system exploration missions often requires optical navigation techniques in order to achieve the orbit determination precision necessary to fulfill mission science objectives. Optical navigation relies heavily on the imaging instruments on-board the spacecraft, which each need to be individually calibrated to characterize and model their optical properties. While a preliminary calibration of the instruments is completed on the ground before launch, an in-flight calibration is necessary to refine the results of the preliminary calibration and achieve the post-launch accuracy levels necessary for optical navigation. This paper presents the procedure and results of the in-flight calibration of the optical navigation imagers on-board NASAs OSIRIS-REx spacecraft. This spacecraft is currently en route to the asteroid Bennu (101955), which will be the smallest body that NASA has ever attempted to orbit. Orbiting such a small body presents unique challenges and requires high-precision optical navigation, which is not possible without proper camera calibration.