A comic book adaptation of Star Trek: The Motion Picture was published as a single-issue Marvel Comics "Super Special Magazine" dated December 1979. When Marvel launched their monthly Star Trek comic a few months later, the adaptation was reprinted across the first three issues, starting with #1 dated April 1980. It is the 3-parter which I have in my collection.
Above: Issue #1 April 1980.
Above: Issue #2 May 1980.
Above: Issue #3 June 1980.
Marvel's monthly Star Trek title lasted for eighteen issues. I bought all eighteen in one shot during the Maplecon 5 convention, on either 15 July or 16 July 1983.