It's not Escape Velocity, but Maelstrom was open-sourced [1]!
A while ago I forked a version and changed the braking power-up to be controlled by a button press, instead of always active [2]. It was cool to fix something that always bugged me in a game I played when I was a kid.
Works great! If you're on Ubuntu/Debian/etc, you'll need to apt install libsdl1.2-dev and libsdl-net1.2-dev. I thought something was wrong when the build took less than 2 seconds, but it turns out computers have gotten faster in the last 25 years.