Prevent subsequent key input

Hey guys.

So I'm pretty new to Unity. Currently, I'm creating a bowling game. But I have some trouble figuring out how to prevent additional input once an input is entered. This is my code:

 void Update()
     {
         if (Input.GetKeyUp(KeyCode.Space))
             GetComponent<Rigidbody>().AddForce(new Vector3(-force, 0, 0));
        if (Input.GetKeyUp(KeyCode.LeftArrow))
             GetComponent<Rigidbody>().AddForce(new Vector3(0, 0, -5), ForceMode.Impulse);
         if (Input.GetKeyUp(KeyCode.RightArrow))
             GetComponent<Rigidbody>().AddForce(new Vector3(0, 0, 5), ForceMode.Impulse)

When I pressed Space, I launched the ball from stationary to my force values. But when I keep pressing Space multiple times, the force just adds up. How to prevent that from happening? I just only want the Space input for once and prevent subsequent Space input so that the ball does not speeding up.