Comsat was created by the Communications Satellite Act of 1962 and led an interesting and tortuous life until 2000 when it merged with Lockheed Martin Global Telecommunications (LMGT). LMGT shut down operations in December 2001. COMSAT’s story is well told in David J. Whalen’s book “The Rise and Fall of COMSAT” published in 2014.
From 1971 through 1992 COMSAT published semiannually a technical journal that contains a number of articles concerning various Hughes satellites. These journals are available online and can be accessed at http://www.comsatlegacy.com/CTR.html From 1990 to 1992 COMSAT devoted five journals to a description of the Hughes INTELSAT VI satellite and it operations. These are summarized below and can be found at the link indicated above.
COMSAT TECHNICAL REVIEW Volume 20 Number 2 Fall 1990
INTELSAT VI: The Communications System (This issue is particularly interesting as it describes the INTELSAT procurement process and the evaluation of the Hughes and Lockheed INTELSAT VI proposals.
COMSAT TECHNICAL REVIEW VOLUME 21 Number 1 SPRING 1991
INTELSAT VI Spacecraft Bus Design
COMSAT TECHNICAL REVIEW Volume 21 Number 2, Fall 1991
INTELSAT VI: From Spacecraft to Satellite Operation
COMSAT TECHNICAL REVIEW Volume 22 Number 1, Spring 1992
INTELSAT VI: System and Applications
INTELSAT 603 Reboost
COMSAT TECHNICAL REVIEW Volume 22 Number 2, Fall 1992
SSTDMA in the INTELSAT VI System
Our Space Heritage 1960-2000 