One of the most important issues for microgravity experiments on low-Earth orbiting spacecraft is the “residual acceleration.” The residual acceleration is induced by various kinds of environmental disturbance sources (e. g. gravity gradient, rotational motion of spacecraft, solar radiation pressure, aerodynamic drag, vibration caused by spacecraft's flexibility, rotating machines and crew activities, etc.). To minimize the residual acceleration, it is essential to know what the residual acceleration is and how it is induced. In this paper, the residual acceleration is formulated in terms of dynamic variables describing spacecraft's attitude and orbital motion and is evaluated by numerical simulations using a simple rigid spacecraft model. The results are summarized as a function of time, or a position within spacecraft for typical attitude control schemes, which identifies the effects of environmental disturbance sources.