Payload Assist Module

SBS-3 satellite with PAM-D stage inside the space shuttle

PAM-D stage in assembly

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:

• PAM-A (Atlas class), development broken off
• PAM-D (Delta class), uses a Star-48B rocket motor
• PAM-D2 (Delta class), uses a Star-63 rocket motor
• PAM-S (Special) as a kick motor for the space probe Ulysses

Today the PAM-D is only used as the third stage of the Delta II.

A small fragment from a spent PAM-D came close to colliding with the International Space Station in March 2009[1] [2].

External links

• the upper stages of the space shuttle (dt.)