Space People? It's more likely than you think: Nebula Genasi

Genasi are a very particular group of beings, steaming from the union of elemental planes and mortals. Nebula genasi have an origin in... pain, loss.
As Nephila was being banished from the sky by her parents, Stasi and Enki, she desperately tried to stay in the sky. Grabbing onto anything she could, nearby stars, clouds, anything. But it was all in vain. Everything they tried to grab onto disappered into dust, or so she thought. Down she fell. The image of her parents becoming smaller and smaller. At some point the fall, she started to laugh. The absurdity of it all, a god being banished to the mortal plane; it was too much. Their arms spread out, feeling the rushing wind slip through their fingers.
Many said it was a spectacle when she fell. A glowing star falling to Astalia. However, she was not the only thing to fall onto the land. A piece of the sky caught under her finger nails came down with her. Just as they touched the ground, pieces of it slowly became dislodged and floated off into the wind. Some found their way into rivers, meadows, and caves. But a few lucky ones found their way into houses, changing those future generations.
The first recorded nebula genasi was born a few months after the Fall of Nephila, a child of the stars. Soon other cases would come up and causing other speculations to come about. Some say it was a more direct involvment of the gods while others stick to their guns with the Nephila tale. Either way, nebula genasi are truely people from out of this world.