ships and pathfinders and as independent strike aircraft. It was demonstrated that the B-58 could carry iron bombs on the wing root bomb racks that had earlier been added to accommodate four Mk. 43 nuclear weapons. Iron bombs of varying weights up to 3.000 pounds were dropped, usually from low altitudes and at speeds of 600 knots. Almost all of the drops were visual, with the AN/ASQ-42 system rarely being used. However, the fear that the B-58's integral wing tanks would make it vulnerable to ground fire during low-altitude delivery lead to the abandonment of the program. The wing operated a B-58 combat crew training school (CCTS), August 1965 – December 1969, and gained a Boeing EC-135 Post-Attack Command Control System (PACCS) mission with the 3d PACCS Squadron in mid-1966. After 26 years of bearing the name Bunker Hill, the base was renamed Grissom Air Force Base on 12 May 1968 after Lieutenant Colonel Virgil I. "Gus" Grissom, USAF, a native of Mitchell, Indiana, who was one of the original seven Mercury astronauts. Having later commanded the Gemini 3 mission in 1965, Lieutenant Colonel Grissom was assigned as commander for the first manned Apollo mission, but was killed with the rest of his crew during a fire in his Apollo 1 capsule during a pre-launch rehearsal on Pad 34 at Cape Kennedy, Florida in January 1967. The active service life of the B-58 was destined to be rather short. Phaseout of the B-58 fleet was ordered by Secretary of Defense Robert McNamara in December 1965, since it was felt that the high-altitude performance of the B-58 could no longer guarantee success against increasingly sophisticated Soviet air defenses, particularly high-altitude surface-to-air missiles such as the SA-2 Guideline. At that time, Secretary McNamara also announced that the F-111 would be built for both the U.S. Air Force and U.S. Navy. McNamara further proposed that a SAC variant of the new F-111, to be designated FB-111A, along with improvements in the Air Force Minuteman and Navy Polaris missile systems and modernization of the subsonic Boeing B-52, would enhance strategic deterrence and make the B-58 superfluous to the needs of the USAF. The first B-58 to go into long-term storage was B-58A (AF Serial No. 59-2446) which flew to Davis–Monthan Air Force Base, Arizona on 5 November 1969. Once underway, the B-58 retirement program moved relatively rapidly. The retirement was completed on 16 January