Starfield: All 17 Traits explained

Spaced

"Your body has become acclimated to space. Health and oxygen are increased when in space, but decreased when on the surface. (Can’t be combined with Terra Firma)"

This is kind of similar to Alien DNA in that you get increased Health and Oxygen, but only when you are in space. The trade-off is that being on a planet’s surface will decrease both of them. With how much exploring you do on planet surfaces, not sure this is a good deal.

Terra Firma

"You’ve never acclimated to space. Health and oxygen are increased when on the surface, but decreased when you’re in space. (Can’t be combined with Spaced)."

The opposite of Space, you get increased health and oxygen when on a planet’s surface. I chose this one and absolutely loved it but late game, when you have improved jetpack capabilities and have increased health, I don’t think it’s terribly useful.

United Colonies Native

"You gain access to special United Colonies dialogue options, and better rewards from some missions given by the faction. However, crime bounty by other factions is greatly increased (Can’t be combined with any other faction allegiance trait.)"

This is another faction-focused trait that provides you extra perks with the United Colonies. Better missions and rewards but increased bounties from others.