Out of curiosity how did you get the missile to follow the tank?
It wasn't actually too much code. I was able piece it together from examples online. It probably going to be ugly but I pasted it below. The first line move the missile towards the player, the rest rotate the missile to point at the player.
transform.position = Vector3.MoveTowards(transform.position, player.transform.position, 2.8f * Time.deltaTime);
Vector2 movementDirection = player.transform.position - transform.position;
movementDirection.Normalize();
if (movementDirection != Vector2.zero)
{
Quaternion toRotation = Quaternion.LookRotation(Vector3.forward, movementDirection);
transform.rotation = Quaternion.RotateTowards(transform.rotation, toRotation, 720 * Time.deltaTime);
}