Spanish defense and information technology company Indra signed a licensing agreement with Northrop Grumman, obtaining rights to manufacture and market Northrop Grumman's ASR-12 air traffic control radar system outside the United States. The ASR-12 radar, designed and produced by Northrop Grumman's Baltimore-based Electronic Systems sector, is an updated version of its ASR-9 radar. Both versions are used by air traffic controllers to monitor the approach, landing and departure of aircraft. The ASR-9 radar system is operating at 135 U.S. airports in addition to 18 airports in other nations. The ASR-12 radar is currently operational in six nations worldwide. Indra's air traffic management systems are currently fielded in 40 countries.