public synchronized ArrayList<SpaceCraft> collisionCheck( SpaceCraft mover ) {
		
		// List of ships in collision
		ArrayList<SpaceCraft>  destroyedShips = null;
		
		// Go through all the ships in the sector and compare
		// each against mover
		for( SpaceCraft target: inSector ) {

			// Have mover and the target ship collided
			if ( !target.equals(mover) && inCollision( target, mover)) {

				// A collision has occurred. Create a list to hold the destroyed ships
				destroyedShips = new ArrayList<SpaceCraft>();
				
				// Check for head-on collision.
				if ( opposingHeading( mover , target) ) {

					// Remove move and add to destroyed ship list
					removeSpaceCraft( mover );
					destroyedShips.add( mover );
				}
				
				// Add the ship that was hit to the destroyed ship list
				removeSpaceCraft( target );
				destroyedShips.add( target );
				
				// Return the ship collided with 
				return destroyedShips;	
			}
			
		} // end for

		// no  collision occurred
		return null;

	} // end collisionCheck