Spacecraft --- Space Shuttle --- Position and Orbit

To change the direction that the orbiter is pointed (attitude), the reaction control system (RCS) located on the nose and OMS pods of the aft fuselage must be used.
The RCS has 14 jets that can move the orbiter along each axis of rotation (pitch, roll, yaw). The RCS thrusters burn monomethyl hydrazine fuel and nitrogen tetroxide oxidizer just like the OMS engines described in the section Basic Structure and Launching. Attitude changes are required for deploying satellites or for pointing (mapping instruments, telescopes) at the Earth or stars. Firing the OMS engines must be needed to change orbits.
Also, these engines change the velocity of the orbiter to place it in a higher or lower orbit.

Basic Structure and Launching Position and Orbit Communication Navigation Power Computer Returning to Earth