What is the name of that old pc game that resembles an early version of Starcraft and Starship Troopers?

It resembles Starcraft in several ways. 1, you must harvest gas in order to build things, but not crystals. 2, u must protect the mother ship or mission failure. 3, you can build scouts. Ways it differs from Starcraft. 1. it is not multiplayer capable. 2, it is a first and third person shooter. 3. you have can enter and exit an vehicle in the game. 4, when your vehicle is destroyed you are ejected out and can walk around in your space suit and shoot with a gun. It resemble Starship Troopers because you fight weird alien creatures. Please help me find this one of a kind game... Thank you!