PAM (Payload Assist Module) is a modular upper stage operated with solid propellant, used with Space Shuttle, Delta, and Titan launchers. The rocket was used to carry satellites from a low earth orbit to a geostationary transfer orbit or an interplanetary course. The payload was spin stabilized by being mounted on a rotating plate. Originally developed for the Space Shuttles, different versions of the PAM followed:
Today the PAM-D is only used as the third stage of the Delta II.