Unwanted results from 2D collisions?

Hey all. I have been building a game with an asteroids style controller, however I have run into an issue. When the player lands on planets (similar to Cosmochoria) the character seems to constantly behave as if there was a slight turning force, each time it occurs in a random direction. If it helps the character is using a 2D box collider and a rigidbody.
Thanks in advance.

You can set a fixed angle: