Well, that's a relief.
It was David Milner, the Australian Editor of Game Informer, that pitched the obvious (in hindsight) question: will you need PlayStation Plus to play No Man's Sky. The answer, thankfully, is no.
The reasoning: the No Man's Sky universe is so vast. The chances of you running into another player in that universe is so astronomically small that it's practically a single-player experience by default. Makes sense.
But it's nice to be sure.
Thanks Game Informer