Is there a way to make low gravity?

I am trying to make a game in space, but I want the player to be able to interact with objects in low/no gravity? Is there a simple way to change this?

You can set global gravity to any value you like in World Settings > Physics > Override World Gravity.

Thanks. Is there a way to change this through Blueprints, say if they walked into a boxtrigger?

You can edit per-character gravity by setting the gravity scale value in the character movement.