Need help identifying old game

Old game I used to play on Windows 95 or 98. I believe it started with a d. Opening movie was a ship (yours) flying up to and into a metal door built into an asteroid. You basically flew around, shot rebel mining robots (I think), got weapon powerups and stuff like that. I remember some weapons were concussive missiles, a Vulcan cannon, and a plasma laser gun thingy.

Can anyone help me?

Descent