Maybe you upset the Sentinels by strip mining an entire planet or by murdering too many lizard-puppies. Maybe you ran afoul of space pirates. No matter the cause, you're dead. You found yourself facing an existential quote and a couple seconds of blackness in which to contemplate your failures. Now what?
Death is not the end of your journey in No Man's Sky. You'll find yourself returned to your most recent Restore Point with an empty inventory and a broken piece of technology. Either your ship's or your suit's inventory will be cleaned out, depending on how you died. (In the case below, we were unjustly murdered in cold blood by gravity).
Upon reincarnation, you'll find a helpful new icon that will lead you back to the scene of your death. Following that icon, either on a planet's surface or in space, will bring you to a gravestone of sorts. Interact with it to reclaim your resources and refill your inventory.
Now, dust yourself off, fix what's broken and get back to adventuring. You've got a universe to explore.