Electrochromic Orbit Control for Smart-Dust Devices

Recent advances in microelectromechanical systems technology are leading to spacecraft that are the shape and size of computer chips, so-called SpaceChips or smart-dust devices. These devices can offer highly distributed sensing when used in future swarm applications. However, they currently lack a feasible strategy for active orbit control. This paper proposes an orbit-control methodology for future SpaceChip devices, which is based on exploiting the effects of solar radiation pressure using electrochromic coatings. The concept presented makes use of the high area-to-mass ratio of these devices and, consequently, the large force exerted upon them by solar radiation pressure to control their orbit evolution by altering their surface optical properties. The orbital evolution of SpaceChips due to solar radiation pressure can be represented by a Hamiltonian system, allowing an analytic development of the control methodology. The motion in the orbital element phase space resembles that of a linear oscillator, which is used to formulate a switching control law. Additional perturbations and the effect of eclipses are accounted for by modifying the linearized equations of the secular change in orbital elements around an equilibrium point in the phase space of the problem. Finally, the effectiveness of the method is demonstrated in a test case scenario.