Project 10073 Record Card and Air Intelligence Information Report — 26 March 1959

On 26 March 1959, a B-52 aircraft participating in a HEADSTART II mission over Northern Montana reported being trailed by an unidentified object. The B-52 crew, flying at 32,000 feet, observed the object on their defensive radar and visually identified red and green blinking lights. The object maintained a position behind the B-52 for approximately one hour. An F-89J interceptor, call sign BOARDPIPE 27, was scrambled from Malmstrom Air Force Base to identify the object. The F-89J crew established radar contact and visual contact, noting the object's high speed, acceleration, and ability to climb beyond the interceptor's service ceiling. The object performed evasive maneuvers, including a 70-degree turn, and eventually climbed out of range. The interceptor pilot noted the object appeared to be a medium-sized aircraft with a delta or swept-wing configuration. Subsequent analysis by the Air Technical Intelligence Center and Air Defense Command considered the possibility that the object utilized radar-absorbent materials, given the difficulty in maintaining radar contact. However, investigators noted that the object's behavior was consistent with a high-performance aircraft. The incident was extensively documented through multiple reports, including supplements to AF Form 112, and involved coordination between various radar sites, including GCI stations and the 1006th AISS. Despite the lack of a definitive identification, the official conclusion suggested the object was likely a high-performance fighter interceptor of unknown origin. The investigation also noted that the F-89J's MG-12 fire control radar was found to be out of calibration following the event, which may have impacted the data collected.