When should a newtonian spaceship start slowing down?

I’m working on a 2d (top down) spaceship shooter with newtonian physics. I’m having some trouble with the ship AI though.

I want it to begin to slow down when it is nearing it’s target, the trouble is, how does it know when to start slowing down? I guess it would be a factor of the mass of the ship (no drag), the velocity and the maximum reverse thrust (applied via rigidbody.AddForce(transform.right * (-maxThrust * Time.deltaTime));).

Sorry for the maths problem :slight_smile:

I derived the formulas. They are:

distance = velocity^2 / (2 * acceleration) or

distance = velocity^2 * mass / (2 * thrustForce)