On the application of reflectivity control devices in spacecraft attitude control

This paper investigates the application of reflectivity control devices in spacecraft attitude control. In reflectivity control devices, in particular, the polymer-dispersed liquid–crystal type, the light transmission properties of the film can be altered from transparent to opaque by adjusting the amount of applied voltage. This technology has previously been applied to residential and commercial buildings and, recently, it has been widely adopted in the automotive industry for purposes such as electrochromic glass roofs. Since spacecraft in orbit receive a continuous flow of photons emitted from the Sun (when in the sunlit portion of their orbits), the momentum transferred from these photons to the spacecraft can be utilized for attitude and orbit control. The focus of this paper is on attitude control through strategically adjusting the transparency of reflectivity-control panels attached to the spacecraft away from its center of mass. In this paper, a conceptual design for a spacecraft equipped with reflectivity-control device panels is presented, and the equations of attitude motion coupled with control torques produced by these devices are derived. Furthermore, a control strategy for detumbling a small satellite, such as a CubeSat, is investigated. To assess the viability of reflectivity-control technology in spacecraft attitude control, a number of case studies are presented. The performance of these devices is discussed in light of the results obtained from the numerical simulations.