Ooh! I grew up with this game; someone brought a working Atari 800 to the Maker Faire a couple of years ago, and I was able to play a game from start to finish without referencing the manual. The Internet Archive has:

* the game in an emulator, so you can play it in your browser: https://archive.org/details/a8b_cart_Star_Raiders_1979_Atari...

* the manual: https://archive.org/details/agm_star_raiders

* the unreleased sequel: https://archive.org/details/StarRaidersII_Wilmunder