Tailandia.Sisaket · the "UFO" that was the fourth stage of a Scout rocket (1965)

In the spring of 1965, in Sisaket province, in north-eastern Thailand near the Cambodian border, a metal object turned up that was said to have "fallen from the sky". The provincial governor handed it to the Royal Thai Air Force, which asked the US Joint Military Advisory Group in the country for help in identifying it. On 25 May 1965, Colonel B. B. Beck, the advisory group's intelligence chief, sent it to the Air Force's Foreign Technology Division at Wright-Patterson Air Force Base, with a letter headed "Unidentified Flying Object" and citing the Air Force regulation on UFOs. The letter warned that there was no information on sightings or eyewitnesses to the fall.

At Wright-Patterson, where Project Blue Book was also based, the object was examined and judged to appear to be "part of the igniting mechanism of a US rocket". On 9 July, Colonel Eric T. de Jonckheere, the division's deputy for technology, asked the Ballistic Systems Division in California for help so that "an adequate reply" could be made to the advisory group. It could not be positively identified there either, but the markings pointed to a specific manufacturer, and the object ended up with the company that had built the motor. Meanwhile, the US military command in Thailand asked by telex about the status of the identification: according to the telex, the Thai government was "anxious" for information.

On 5 August, in a telephone conversation that Blue Book noted down, an official of the Allegany Ballistics Laboratory in West Virginia, operated by the Hercules Powder Company, explained what it was: the object came from a Scout rocket launched from Wallops Island on 16 December 1964 on the San Marco mission, a joint programme with Italy to measure air density. The laboratory would photograph it and probably hand it to NASA. On 29 September, Hercules sent the full data: the parts were from a motor built at Allegany for NASA's Langley Research Center; model Jato 24DS-5850 X258, manufactured on 13 November 1964, serial number RH-75, fourth stage of Scout rocket S-137 on the San Marco mission; the satellite, meant to measure atmospheric density, had been placed in a 115-by-350-mile orbit. The letter put the fall in Sisaket province "approximately May 1964", and on 27 October an erratum corrected it to "approximately May 1965". The parts stayed at the laboratory. The Blue Book card closed the case as "Other (Scout rocket)" and noted that the object had been returned to the manufacturer.

Jonathan McDowell's satellite catalogue settles the last doubt. The San Marco mission put San Marco 1, the first Italian satellite, launched by an Italian team from Wallops, into orbit on 15 December 1964 (universal time). Its fourth stage is listed in the catalogue as 1964-084B, an Altair 2 X-258 motor with serial number RH-75, the same one given in the Hercules letter, and a re-entry on 7 February 1965. The date used by Hercules and the Air Force, "approximately May", was when the object was handed over, not when it fell.

It is the corpus's first case in Thailand, and one of the few in which the fallen object is identified down to its serial number. The documentary chain is complete and first-hand: the advisory group's letter, the Foreign Technology Division's inquiry, Blue Book's telephone note, the manufacturer's letter with the motor data and its erratum. And McDowell's catalogue, built from independent sources, gives the same serial number. Rarely is an object that reached Blue Book as a "UFO" closed with such precision.

The case is also a good example of how the regulation worked. In 1965 the Air Force required any unidentified aerial object to be processed as an "unidentified flying object", and that included debris that fell from the sky without anyone seeing it fall. So a US rocket motor picked up by a Thai governor travelled to Ohio labelled as a UFO, passed through the office that studied enemy technology and ended up at the laboratory that had built it. It is the same mechanism as in ↗ and ↗, but seen from the American side: here Washington did not know at first that the object was its own, and took four months to find out.

It also carries a lesson about dates. For months, every document said the object had fallen "approximately May", because that was when it reached American hands; the manufacturer even wrote 1964 and had to correct it. The catalogue shows the stage re-entered in February. The date of a find is not the date of a fall, and an object that "fell from the sky" may have spent weeks in a field before anyone reported it. The case weighs almost entirely on the mundane explanation.