Later that summer, Mayfield purchased an HP-35 calculator and often visited the local Hewlett-Packard sales office. The staff there offered to let him use the HP 2000C minicomputer at the office if he would create a version of his "Star Trek" game for it; as the version of the BASIC programming language on the computer was different from the Sigma 7, he elected to abandon the Sigma 7 version and rewrite the program from scratch. He completed it on October 20, 1972, and the game was added to the HP public domain Contributed Program library of software as "STTR1" in February 1973, with Mayfield attributing the game to Centerline Engineering, a company he was considering starting. It was also published in the People's Computer Company newsletter, and republished in their collection book, "What to Do After You Hit Return" (1975).