It is a do-as-you-please type of experience; both single and multiplayer are available.
Are you familiar with games like No Man's Sky? It is similar in the sense that it is a semi-realistic space exploration, sandbox sort of game. Infinite universe, full-scale generated planets; a plethora of spacecraft and game styles to choose from. Build a crew and roam the universe completing tasks and engaging in space warfare, or choose a more solitary single-player experience.
It has been in development for over a decade now, having raised over $500,000,000, mostly crowdfunded (the community is very devoted to this project). The project is very ambitious, as the devs wished to have a seamless experience (no loading screens anywhere), along with other aspirations (this meant building the engine and software from scratch).