According to Sean Murray, founder of Hello Games, No Man's Sky will have a "traditional" multiplayer component. During an interview with Gamespot, Murray confirmed that, althought this is a singleplayer game, players will definitely cross paths:
"You can cross paths with other players. That's just not a core component of the game. You're not going out and seeking [other players] out or whatever, but it's lovely to play and just see a little touch of, you know, playing with other people. You and your friends - you know, we're doing the worst possible thing, probably - we're gonna fling you out really far apart."
It kind of reminds us of Journey, which also is a lonely experience, where you occasionally encounter other players. Murray also added that "there is a plan for multiplayer and for people to have a more traditional multiplayer experience within the game," but he's "not going to talk about it now". Murray did confirmed that this will be an evolving game, that will not be finished when released.
No Man's Sky is being released on PlayStation 4, with possible plans for other platforms yet to be announced.