PAM-D with thePhoenix spacecraft. The stage is successivelyspun, fired,yo-yo de-spun and jettisoned.
ThePayload Assist Module (PAM) is a modular upper stage designed and built byMcDonnell Douglas (Boeing), usingThiokol Star-series solid propellant rocket motors. The PAM was used with theSpace Shuttle,Delta, andTitan launchers and carriedsatellites fromlow Earth orbit to a geostationary transfer orbit or an interplanetary course. The payload was spin stabilized by being mounted on a rotating plate.[1] Originally developed for the Space Shuttle, different versions of the PAM were developed:
PAM-A (Atlas class), development terminated; originally to be used on both the Atlas and Space Shuttle, designed for satellites up to 4,400 lb (2,000 kg)
PAM-D (Delta class), uses aStar-48B rocket motor, designed for satellites up to 2,750 lb (1,250 kg)[2]
PAM-DII (Delta class), uses aStar-63 rocket motor, designed for satellites up to 4,150 lb (1,880 kg)[2]
PAM-S (Special), uses a Star-48B as a kick motor for the space probeUlysses[2]
The PAM-D module was used as an optional third stage of the classic Delta rocket. The PAM-D was discontinued after the Challenger accident. A simplified 3rd stage using the STAR-48 motor was employed on Delta II.
On January 12, 2001, a PAM-D module re-entered the atmosphere after a "catastrophic orbital decay".[3] The PAM-D stage, which had been used to launch theGPS satellite2A-11 in 1993, crashed in the sparsely populatedSaudi Arabian desert, where it was positively identified.[3]
