Earth was enslaved and protected by a shield - a red one iirc. You were on a space ship circling the earth and decided to revolt. You had to explore planets, starting with the moon, and mine their resources. Eventually you would run into other civilizations - some friendly, some foe - and build up your technology, your space ship, and eventually free Earth. I remember there being a time limit in the game and if you didnt achieve success, a master race destroyed everything in the universe.
I had a copy of the game on 5 -1/4" disks for the old a: drive if you remember that tech
