Baffle simulation and design with the aim of use in space cameras

There are many devices used today on modern spacecraft to accurately determine their position. Star trackers (space cameras) are the most accurate device in use for determining a spacecraft's position. The star tracker operates automatically, getting images of star patterns within its Field of View (FOV). The stars observed by the camera can then be identified and the orientation of the spacecraft can be calculated. A star tracker is composed of a baffle for removing stray lights, optical system, image sensor, microprocessor and memory. In this paper, basic principles for designing a baffle system, such as determination of baffle dimensions, arrangement of vanes inside the baffle, and coating of surface have been reviewed. We first determined dimensions of a two-stage conical baffle. Then, we calculated positions and height of vane to prohibit diffusely reflected light inside the baffle from entering into the photometer. In order to evaluate performance of the designed baffle system, we have used a ray tracing program using a Monte Carlo method and calculated attenuation factor.