EmptyEpsilon is described as 'places you in the roles of a spaceship's bridge officers, like those seen in Star Trek. While you can play EmptyEpsilon alone or with friends, the best experience involves 6 players working together on each ship'. There are five games similar to EmptyEpsilon for a variety of platforms, including Windows, Steam, Linux, Mac and Playstation. The best alternative is Star Trek™: Bridge Crew. It's not free, so if you're looking for a free alternative, you could try Quintet or Space Nerds In Space. Other EmptyEpsilon like games are PULSAR Lost Colony (Paid) and Artemis Spaceship Bridge Simulator (Paid).
Artemis Spaceship Bridge Simulator lets you turn your living room into the bridge of a spaceship. You and your friends assume the jobs of Captain, Helm, Science, Communication, Engineering, and Weapon Control. Together you operate your ship and defend the sector from evil aliens.