gistfile1.cs

// all this code needs to go in the loop which initialises the asteroids
  bool isStillCheckingLocation = true;
		while(isStillCheckingLocation)
		{
			asteroidStartLocation = new Vector2 (UnityEngine.Random.Range (0, gameWidth),
			                                           UnityEngine.Random.Range (0, gameHeight));
			// we need to make sure the asteroids are not spawned too close to the player
			if( (asteroidStartLocation.x < gameWidth * 0.4f || asteroidStartLocation.x > gameWidth * 0.6f) &&
			   (asteroidStartLocation.y < gameHeight * 0.4f || asteroidStartLocation.y > gameHeight * 0.6f) )
				isStillCheckingLocation = false;
		}