This paper presents gain scheduling (GS) control of a Variable Speed Control Moment Gyroscope (VSCMG) based on sum of squares (SOS). Nonlinear motion equations of the VSCMG are complicated because they contain sine and cosine of angles of gimbals. The dynamics varies depending on an attitude of a spacecraft. In this study, the difficulty of control design of the VSCMG is solved by two methods. ...