Nigeria.Jos · a missionary pilot sees a flashing light overhead

On Saturday, April 2, 1966, at 18:24 GMT (19:24 local time), Bob Ediger, a pilot with the aviation department of the Sudan Interior Mission in Jos, on the central plateau of Nigeria, was watching the sky for satellites when, by his own account, "a most unusual device" crossed directly overhead, heading east. The next day he told NASA about it in an air letter addressed to "National Aeronautics and Space Administration, Cape Kennedy, Florida," apologizing for the lack of a proper address.

Ediger gave two reasons for calling it unusual. The first was its speed: in the 50 to 80 degrees of arc through which he followed it, no more than a minute elapsed. The second was that it blinked very brightly about twice a second, and between flashes seemed invisible. Its brightness was at least that of a first-magnitude star, and directly overhead much greater; its color, that of a white star. There was no sound, and Ediger stressed that Jos is very quiet and high-flying jets are easily heard.

He gave his credentials: more than 4,000 flying hours, including time in U.S. Air Force F-84G jet fighters. He asked to hear back if they had any information, and ended: "I have seen many satellites and in my opinion this object was neither a satellite or an aircraft."

The air letter, sent by Nigerian airmail, bears a receipt stamp from the Office of Information of the Secretary of the Air Force dated April 21, 1966, 9:50 a.m. It passed to Blue Book, which opened a card (the "Project 10073 Record" form) with these entries: one civilian witness, ground-visual observation, one object, course east, one minute, no photographs or physical evidence. The card gives the time as 17:24 GMT, an hour earlier than the letter, and summarizes the track as 50 degrees of arc in one minute, against the letter's 50 to 80; it does not say which time is right. The conclusion was "possible aircraft," with a note: "in view of experience of observer, not a firm identification."

The letter is the testimony of a single observer: a pilot with more than 4,000 flying hours, including time in military jet fighters, who was watching for satellites. There is no photograph or second observation, and the published file contains no reply to his letter.

The only explanation a source proposes is Blue Book's: a possible aircraft, which the project's own card does not treat as firm because of the observer's experience. Against it, Ediger wrote that he heard no sound in a place where high-flying jets are easily heard, and that in his opinion it was neither a satellite nor an aircraft.

An alternative reading comes from a calculation made for this case, which no source proposes. At 18:24 GMT the Sun was some 13 degrees below the horizon at Jos, so the sky was already dark but an object more than about 160 kilometers up was still sunlit. A low-orbit satellite passing through the zenith covers about a degree per second, a pace similar to what Ediger described, and makes no noise; and rapid flashes can come from a spinning object, such as a rocket stage.

It depends on the letter's time: at the card's 17:24 GMT the Sun would have been about 2 degrees above the horizon at Jos, the sky still bright, and a satellite would not have been seen this way. The calculation has also not been checked against a catalog of orbiting objects for that night, and Ediger, who watched satellites, ruled it out.