NAEV is described as 'Naev is a 2D space trading and combat game, in a similar vein to Escape Velocity' and is a Role-playing Game in the Games category. There are eight games similar to NAEV for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and BSD. The best alternative is Endless Sky, which is both free and Open Source. Other NAEV like games are The Ur-Quan Masters (Free, Open Source), Escape Velocity Nova (Paid), nuu (Free, Open Source) and Ascii Sector (Free).
Explore other star systems. Earn money by trading, carrying passengers, or completing missions. Use your earnings to buy a better ship or to upgrade the weapons and engines on your current one. Blow up pirates. Take sides in a civil war.
NUU is to be an open-source (massive) multiplayer game of space trade and combat. NUU is heavily inspired by Ambrosia Software's Escape Velocity. It's excellent open-source cousin naev currently lends NUU it's assets.
Ascii Sector is a free space combat/exploration/trading game for Windows, Mac OS X and Linux. You start with a simple spaceship and can then accept missions or trade goods to earn enough money to upgrade your ship or buy a new one.
Star Sonata is a space-themed massively multiplayer online role-playing game (MMO), that uses a third-person 2d overhead view similar to that of Asteroids. In addition the game offers complex and involved commerce, construction and team systems.