This whole two-game series was written by Derek Brewster and published by Micromega in 1984.
The first game, Codename MAT, was described as a "mammoth space arcade strategy epic". Both games used Brewster's own polar 3D graphics engine, the code for which is only 200 bytes long. The story has the solar system under threat from Myon invaders. MAT ("Mission: Alien Termination") is a teenager implanted with all the combined tactical skills of the planetary leaders. MAT pilots a prototype spacecraft, the USS Centurion, in an attempt to defend the system from the alien's all-out attack. The second game, Codename MAT II, continues the story with a new ship, the Centurion II, which had two different weapons and a more complex damage system – on-board droids could be assigned repair tasks by the player.
Source: Wikipedia, "Codename MAT", available under the CC-BY-SA License.