Mission Planning for the in-orbit Lunar calibrations of the MicroCarb instrument

Abstract: In-orbit calibrations of space instruments are often necessary to ensure the accuracy of the measurements. The Moon provides a target with very predictable characteristics. In this report, the opportunities to perform in-orbit lunar calibrations of the MicroCarb instrument are evaluated and a procedure for conducting the Mission Planning for these calibrations is developed. Through modeling the spacecraft in its orbit, simulations show that continuous observation sequences of up to 48 minutes can be expected each lunation. The variability of the optical properties of the Moon during an opportunity is related to the orientation of the plane of the orbit of the spacecraft with respect to the cone with axis the Moon-Sun direction and apex the center of the Moon that contains the spacecraft. Choosing a value of the phase angle (Sun-Moon-Spacecraft angle) around −20 degrees to plan the lunar calibrations allows to minimize the variations of apparent radiance of the Moon during the observation. The results make it possible to refine the choice of the best moments to plan the lunar calibrations. This also allows the satellite operations team to anticipate the planning of lunar calibrations on the scale of several months.