How to stop drag after reaching a specific speed

Hi everyone,

I have the following code which adds force to a rigidbody2d in a random direction and attempts to set the linear drag to 0 when a specific speed is reached. The problem is that the drag seems to be set to 0 straight away, and I do not understand why, and therefore I am unable to solve the problem

 void Update () {
     if (Input.GetKeyDown ("space")) {
     rb.velocity = Vector3.zero;
     Vector3 dir = Random.onUnitSphere;
     rb.AddForce (dir * 10, ForceMode2D.Impulse);
     }
 
     if (rb.velocity.magnitude <= 1) {
     rb.drag = 0;
     }
 }

Regards Crouz