The career Air Force non-commissioned officers is one of nine was from Philadelphia. He was part of a Central Intelligence Agency-backed covert Air Force mission called Project Heavy Green. Personnel assigned to the super-secret mission operated radar from clandestine sites in Laos and directed U.S. bombers to targets in North Vietnam. Kirk, a radio technician and repairman, and 11 other men were believed killed in an enemy raid on one of the radar sites on March Ii, 1968. Even if Kirk had survived the attack, he probably would not have survived the intensive bombing three days later by American B-52 bombers sent to destroy evidence of the covert mission, according to classified documents released years later in connection with lawsuits against the Air Force by his son, Rudy, and the next of kin of some of the other men. "He said he might not return," recalled Rudy Kirk, who last saw his father boarding a bus in Bellingham, Wash., in the fall of 1967. Kirk told his wife and two sons that he and about 60 other men chosen for the mission would be posing as civilians working for the Lockheed Aircraft Corp. for security reasons. The 39-year-old sergeant entered the Air Force in 1951 after attending Northeast High School. It wasn't until 1982 that Project Heavy Green was declassified and Kirk was posthumously reinstated in the military.