Payload Assist Module
The Payload Assist Module (PAM ) is a powered solid propellant modular upper stage, which was used for both the Space Shuttle and the Delta and Titan rocket to carry satellites in low orbit to a geostationary transfer orbit or interplanetary train. The PAM - level stabilization is achieved by rotation (spin stabilization).
For use on the Space Shuttle designed different versions of the kick stage were planned by an additional letter carrier rocket named, whose payload capacity should reach from aboard the space shuttle:
- PAM -A ( Atlas - class), development completed, never used
- PAM D (delta - class), uses a star -48B rocket motor
- PAM -D2 (Delta II class ), uses a Star -63 rocket engine
- PAM -S ( Special) as a kick motor for the Ulysses spacecraft
PAM D was used to 2009 as the third stage of the Delta -II.