Trek73 is a computer space-battle simulation based on the original Star Trek television series. It was written in 1973 in the BASIC programming language and played on a Teletype connected to a HP 2000 computer. Trek73 was unique in its day because it was more than just a board game with a computer player. It involved the calculation of the trajectories of the virtual ships and projectiles with enemy ships controlled by a relatively sophisticated AI. The addition of dialog and situations from the original Star Trek series made this game a favorite of early players and future programmers. It had a long-lasting influence and was revised and recoded through the 1980s and 90s and it can still be played today in a number of forms.