Aliens are the NPC`s in the game No Man's Sky. You can become friends with them so you could get better blueprints from the blueprint trader on a Space Station. You can also barter with them to get Nanite clusters or to get unites. You can also ask them about points of interest so they are like Signal Scanners. You can also ask them to work at your base at your terminals if you decide to build a base. You can also buy Starships and supplies from them. You could get blueprints from them from points of interest.