It's called Freespace2 Open, or FS2_Open. I play it on Linux and it's amazing. The graphics quality and explosions are life-like and impressive.
In April of 2002, Volition released the source code for the FreeSpace 2 engine. Volition has open-sourced the code to FS2 so another group is also making a Battlestar Galatica total conversion which is awesome. See http://www.game-warden.com/bsg/
it's still in progress.
Freespace2 also has a unique license agreement that allows for distribution of the game. Specifically:
The Software, including, without limitation, all code, data structures, characters,
images, sounds, text, screens, game play, derivative works and all other elements of the
Software may not be copied (except as provided below), resold, rented, leased,
distributed (electronically or otherwise), used on pay-per-play, coin-op or other
or-charge basis, or for any commercial purpose. You may make copies of the Software
for your personal noncommercial home entertainment use and to give to friends and
acquaintances on a no cost noncommercial basis. This limited right to copy the
Software expressly excludes any copying or distribution of the Software on a commercial
basis, including, without limitation, bundling the product with any other product or
service and any give away of the Software in connection with another product or service.
Any permissions granted herein are provided on a
temporary basis and can be withdrawn by Interplay Productions at any time. All rights not
expressly granted are reserved.
The original FS2 CD's are available here:
FS2_Open, you'll need the MediaVPs for the advanced effects. Follow the FAQ for more information:
I am running the 3.6.7 Media VP's with the offical tarball release I compiled from source. I am running with the follow command:
luser@zd7000:~/freespace2$ cat gofs2