North American Aerospace Defense Command (NORAD) and U.S. Northern Command (USNORTHCOM) conducts VIGILANT SHIELD 19 (VS 19) in October 2018. This is NORAD and USNORTHCOM's annual Tier 1 Homeland Defense exercise.North American Aerospace Defense Command (NORAD) and U.S. Northern Command (USNORTHCOM) conducts VIGILANT SHIELD 19 (VS 19) in October 2018. This is NORAD and USNORTHCOM's annual Tier 1 Homeland Defense exercise.