Invasion Orion is a 1979 science fiction strategy game written and published by Automated Simulations (who would become Epyx in 1983). It was a single- or two-player sequel to the original two-player Starfleet Orion, which had been published late in 1978. The game was originally written in BASIC for the Commodore PET and TRS-80, but later ported to other early home computer platforms including the Atari 8-bit family, and Apple II.
The gamefield was a thirty-two high by sixty-four wide grid of possible locations (the game manual contains a typo, stating these are 34 × 62). The map could contain ships, stacked on the same grid space if needed, as well as planets and other objects. The game was turn based, and in two-player games the players took turns at the keyboard to enter their commands, which were then carried out simultaneously. Each player controlled one or more ships, and the game continued until one or both were destroyed, or escaped by flying off the playfield.
Source: Wikipedia, "Invasion Orion", available under the CC-BY-SA License.