The files now available online are drawn from Project Blue Book, a 17-year-long US Air Force study into UFO reports
Thousands of US government documents on UFOs are available to search online for the first time.
The files – which include pictures of supposed UFOs and interviews with those who say they encountered extraterrestrial life – are drawn from Project Blue Book, a 17-year-long US Air Force study into UFO reports.
While Project Blue Book has been declassified since the 1980s, it has only been available to view in American government archives and in scattered postings across the internet.
Now, for the first time, Project Blue Book and two smaller government studies are accessible in a searchable online database.
The 129,491 pages contain more than 10,000 cases of possible sightings stretching from the late 1940s to the late 1960s.
The online archive, known as the Black Vault, is the work of John Greenewald, a freelance television producer from California.
Mr Greenewald, 33, first began submitting requests to the US government for its UFO files when he was 15 and has spent years researching the topic.
While he spent months compiling the Black Vault archive, Mr Greenewald believes it represents only “the tip of the iceberg” and the government knows far more about UFOs than it has made public.
He described Project Blue Book as a “PR campaign” designed to offer innocent explanations for widespread UFO sightings, for example claiming that a possible sighting was swamp gas or a weather balloon.
“Beginning in 1952 there was a rash of UFO sightings from coast to coast but mainly in Washington DC. It was creating a panic: Were we being invaded by the Soviets? Was it left over Nazi technology? We were barely a decade on from Pearl Harbour and tensions were running high,” Mr Greenewald told the Telegraph.
“Blue Book essentially became this public PR campaign to calm people’s nerves.”
Among the most compelling incidents documented in the Blue Book files is an episode from January 1948, when an unidentified object was spotted near a US Air Force base in Kentucky.
Four P-51 fighter aircraft were dispatched to pursue the object, which one pilot described as a “metallic object of tremendous size”.
Three of the fighters eventually broke off the pursuit but one pilot, a 25-year-old Captain Thomas Mantell, continued to chase it to above 20,000 feet. The pilot then apparently blacked out from lack of oxygen and was killed as his plane crashed to the ground.
“These were the most highly trained military pilots in the world but there was something about this object that meant he wouldn’t break off his pursuit,” Mr Greenewald said.
Among the possible explanations offered by Air Force investigators for what became known as the “Mantell Incident” is that the pilot had either Venus for a flying aircraft or else had spotted a secret Navy weather balloon.
Raf Sanchez (telegraph.co.uk)