This paper discusses the design and simulation of LightSail-1’s attitude determination and control system. LightSail-1 will launch in 2011 and deploy a 32 m2 mylar sail from a 3U CubeSat with the intent of measuring thrust from solar pressure and raising the orbit. The spacecraft will be actively controlled with magnetorquers and a momentum wheel. The various control modes throughout the short mission lifetime include detumble, sun-pointing, and orbit raising. Each one of these modes is simulated in MatLab, and the assumptions and limitations of the MatLab model are discussed. The simulations show that the spacecraft will detumble in 90 minutes after ejection from the P-POD and demonstrate successful sun-pointing within two orbit periods. Orbit raising will require two rapid 90° slew maneuvers every orbit which are accomplished with the momentum wheel
