3d kiematic rigid

use translate or set_translate is easier

object.translate(Vector3(0, 1, 0)) moves the object +1 unit (adds 1 to y)

object.set_translation(Vector3(4,5,6)) moves the object to t 4x, 5y, 6z

for a rigid body you can also use .apply_impulse(1, Vector(0,1,0)) give it a jolt. I can't remember if that's how you use it. Look it up. Only for rigidbody tho

i recommend using kinematic body and .move function cause is way easier and it produces linear motion. the asteroids themselves can be rigidbody.

and is body not dob