Flights of F-102 interceptors from the 509th Fighter-Interceptor Squadron began to deploy to Tan Son Nhut AB in March 1962 to provide air defense against the unlikely event that North Vietnamese aircraft would attack the South. They also deployed to Don Muang RTAFB near Bangkok, Thailand and began exchanging rotational duty with the 16th FIS based at Naha AB on Okinawa. In 1965, operating under the code-name "Project Stovepipe", 509th FIS F-102s used their heat sinking Falcon missiles to lock onto heat sources over the Ho Chi Minh Trail at night, often Viet Cong campfires. The F-102s soon switched to a day role, firing the 12 unguided FFAR rockets from the missile bays, using the optical sight. 618-day sorties were flown, the last one being flown at the end of 1965.