It was July 1971 that AMSAT submitted the initial proposal to NASA.
Here is some information ANS received from Perry Klein, W3PK, who worked on the proposal:
SB SAT @ AMSAT $ANS-219.06 AMSAT History: 40th Anniversary of First Synchronous Satellite Proposal
AMSAT News Service Bulletin 219.06
From AMSAT HQ SILVER SPRING, MD.
August 7, 2011 To All RADIO AMATEURS BID: $ANS-219.06
July 24 marked the 40th anniversary of AMSAT's original SYNCART proposal to NASA, in 1971, to fly a Synchronous Amateur Radio Transponder on NASA's Applications Technology Satellite ATS-G. NASA's response to our proposal appeared to be favorable, but unfortunately NASA cancelled the ATS-G mission.
The SYNCART proposal is on AMSAT-DL's web site at for those who would like to read it. It gives the justification why NASA should fly it for free, listing a number of amateur experiments and applications, most of which would still apply today.
The 1971 WARC on Space Technology was held around the same time (June 7 - July 17, 1971, in Geneva). That's the ITU conference that established the amateur-satellite service and allocated frequencies to it.
Several satellite manufacturers are now advertising that they host pay- loads aboard their satellite platforms. Think how it would transform amateur radio if we could get SYNCART packages aboard one or more of them!
Read a copy of the original proposal at: http://www.amsat-dl.org/images/stories/satellites/syncart/sync.pdf
AMSAT-DL article (in German) at: http://www.amsat-dl.org/index.php/news-mainmenu-97/185-syncart
[ANS thanks AMSAT Past President Perry Klein, W3PK for this information]
/EX
-- 73 de JoAnne K9JKM k9jkm@amsat.org Editor, AMSAT News Service