Solaris

Solaris is a sequel to Star Raiders. The Zylons are back, and are attempting another takeover of the galaxy! Your goal is to destroy all of the Zylon fighters you encounter, rescue cadets that are trapped on Zylon planets, and to find the planet Solaris to protect it from the Zylons. Your spaceship is equipped with a galactic map which can be used to warp to different sectors of the galaxy (mobygames.com)