That approach led to maintenance of a Territorial Defense system. Australia is also a contributor to the National Missile Defense system. This provides a natural defense system. The Air Defense System was continually upgraded. David's Sling is meant to bolster the second tier of Israel's theater missile defense system. MEADS remains a candidate for Poland's Narew short range air defense system procurement. This will result in the merger with Aegis Ballistic Missile Defense System. Two missiles were intercepted by the Pantsir air defense system. It is based on a simplified version of the bacterial CRISPR-Cas9 antiviral defense system. This tracking layer would provide guidance information to the interceptors in the missile defense system. They immediately fortified the city as a bastion of the Japanese defense system. The Iceland Air Defense System monitors Iceland's airspace. Grimes supports Israel's Iron Dome missile defense system. Of these, none was more important than the SAGE interceptor early detection air defense system. It functions as a mobile hub in the strategic defense system of the United States.