Strange collision problem

Unity Engine
1

Hi I make a basic space shooter game.

The space ship has a shield, when a specific button clicked

when I link shield to parent, then collison does not work ?

// HERE COLLISION WORKS
// BUT SHIELD DOES NOT MOVE WITH PARENT
 if(Input.GetKeyDown(shieldKeyInput)){
    	if(!shieldOn){	
            Instantiate(shield, transform.position, transform.rotation);
            shieldOn = true;
   }

// THIS MAKES SHIELD MOVE WITH SPACE SHIP
// BUT THE COLLISION NOT WORKING
 if(Input.GetKeyDown(shieldKeyInput)){
    	if(!shieldOn){	
            var clone = Instantiate(shield, transform.position, transform.rotation);
            clone .transform.parent = gameObject.transform;
            shieldOn = true;
   }
}

// COLLISON SCRIPT OF SHIELD
function OnTriggerEnter (other:Collider) {
	if(other.gameObject.tag == "astroid"){
		shieldStrength--;
		print(shieldStrength);
		print("HIT");
	
	}
}
2

Maybe you can simply drag your shield plane to player and

var shield : Transform;

function Start() {
shield.active = false;
}

if(Input.GetKeyDown(shieldKeyInput)){

shield.active = true;

}
function OnTriggerEnter (other:Collider) {

if(other.gameObject.tag == “astroid”){

shieldStrength–;

print(shieldStrength);

print(“HIT”);

}

}