a 3135N 12720W W of Guadalupe Island, February 1961February 1961

On February 12, 1961, the crew of an RC-121 early warning aircraft spotted a bright white, round object west of Guadalupe Island in the Pacific Ocean. The object appeared as small as a BB pellet held at arm's length and resembled a satellite to the observers. It first became visible five degrees above the horizon and remained in sight for about six minutes as it moved northeast across the sky, finally disappearing at thirty-five degrees above the horizon. The aircraft was heading 312 degrees at the time.

The object moved in a straight track and maintained constant speed and direction. An airborne early warning and control aircraft, a Navy picket vessel, and coastal radars in the area all failed to detect the object on radar. Military records show no aircraft traffic in the area at that time.

The two witnesses were Captain John F. DuPriest, the aircraft commander, and Staff Sergeant Ronald T. Marchman, an air surveillance technician. According to the case file, DuPriest was described as a mature and conscientious individual, while Marchman was young but confident in what he observed. Both men stated they had seen the satellite Echo I on several earlier occasions and believed this object had every appearance of a satellite in orbit.

The 552 Air Early Warning and Control Wing intelligence officer noted that while the observers likely saw a satellite, his office did not have access to trajectory data that would confirm which satellite it was. In the absence of contradictory information, the officer concluded the sighting was probably a satellite. The Air Force's final evaluation listed the case as "unknown," though it also noted "probably balloon" as a secondary assessment.

The complete case file as held by the National Archives is reproduced below across 9 pages of microfilm.