Attitude is the orientation of an aircraft, ship, or spacecraft – its yaw, roll, and pitch – with respect to a particular frame of reference. In the case of a spacecraft in Earth orbit, this frame of reference is usually fixed relative to Earth. However, interplanetary space probes often use bright stars as a frame of reference.
Attitude control is achieving and maintaining a particular orientation, or attitude, in space in order to satisfy mission requirements. Attitude control is usually accomplished using small thrusters in conjunction with a measuring instrument, such as a star sensor. It is maintained by a stabilizing device, such as a gyroscope, or by spin stabilization.