Explained and disputed
Reports later explained as balloons, rockets, satellites, planets, aircraft or other ordinary causes. 122 events, newest first.
Media1953
London publisher T. Werner Laurie issued a book pairing Desmond Leslie's history of sky sightings with George Adamski's claim of meeting a Venusian in 1952. It became a bestseller and a founding text of the contactee movement; Adamski's claims are widely regarded as hoaxes.
Close encounters20 Nov 1952
George Adamski claimed he met a man from Venus beside a landed scout ship near Desert Center, California, after leaving six companions down the road. His 1953 book with Desmond Leslie told the story and sold widely; Blue Book chief Ruppelt recounted it with open skepticism.
Photo: Los Angeles Times, CC BY 4.0
Military20 Sep 1952
During the NATO exercise Mainbrace, a U.S. reporter aboard a carrier in the North Sea photographed a silver sphere that pilots and deck crew were watching. Naval Intelligence found no ship that had launched a balloon, and witnesses split over whether it was one.
Photo: AFC J.J. Swartz, U.S. Navy, Public domain
Military1 Aug 1952
An Air Defense Command radar near Bellefontaine tracked a fast target north of Dayton, and two Wright-Patterson F-86 pilots photographed a silver sphere on gun-camera film. Blue Book first carried it as unknown, then attributed it to a jet and a weather balloon.
Photo: USAF photo 82042 AC, Public domain
Military24 Jul 1952
Two Pentagon-based Air Force colonels flying a B-25 from Hamilton AFB reported three silver, tailless delta craft passing them at high speed over Carson Sink. Blue Book chief Edward Ruppelt wrote that checks for aircraft and balloons found nothing and the case stayed unknown.
Photo: Airwolfhound from Hertfordshire, UK, CC BY-SA 2.0
Military1952
Project Blue Book planned cameras fitted with diffraction gratings to split UFO light into a spectrum and tell meteors, aircraft and balloons apart. Chief Edward Ruppelt later wrote that in tests they could not usefully photograph a bright flare at 450 yards, but were sent out anyway.
Photo: US Air Force, Public domain
Military10 Sep 1951
Army Signal Corps radar at Fort Monmouth tracked fast and high targets over two days, and a T-33 crew reported an object near Sandy Hook. The reports reached Gen. Charles Cabell and led to a revived Project Grudge under Edward Ruppelt; investigators later blamed an airplane and balloons.
Photo: Acroterion, CC BY-SA 4.0
GovernmentJun 1951
A small Ministry of Defence scientific intelligence working party set up in 1950 delivered a secret report concluding that saucer sightings were misidentified aircraft, balloons, astronomical objects, illusions or hoaxes, and advised against further study without material evidence.
Photo: Bernard Hailstone, Public domain
Sightings16 Jan 1951
Two General Mills balloon staff and four local residents watching a Skyhook balloon from the Artesia airport reported two round, dull white objects that flew in, circled the balloon once, and left to the northwest. Edward Ruppelt cited the case after interviewing the General Mills team.
Photo: Office of Naval Research [2] (archive.org), Public domain
Sightings17 Mar 1950
Many residents of Farmington reported large numbers of fast, darting objects on St. Patrick's Day 1950, after scattered reports on the two previous days. Blue Book chief Edward Ruppelt later suggested fragments of a burst Skyhook balloon as the likeliest cause.
Photo: Christopher Nicol, CC BY-SA 3.0
Government27 Dec 1949
The Air Force announced that Project Grudge was closed and released its final report, which attributed saucer reports to misidentification, mild hysteria and hoaxes and recommended cutting the effort back. Grudge continued at a minimal level until Project Blue Book replaced it.
Photo: US Air Force, Public domain
Military24 Apr 1949
A Navy-led crew readying a Skyhook balloon at White Sands Proving Ground said they followed a whitish, elliptical object through a theodolite for about a minute and later worked out an extreme altitude and speed. Astronomer Donald Menzel argued they saw a refracted image of their own balloon.
Photo: Office of Naval Research, Public domain
Government11 Feb 1949
The Air Force renamed Project Sign as Project Grudge, a scaled-down successor that treated most reports as misidentifications. Its 1949 report concluded sightings came from misread natural objects, hoaxes or psychological causes.
Photo: US Air Force, Public domain
Military1949
Astronomer J. Allen Hynek reviewed the 237 reports gathered by the Air Force's Project Sign. His final report attributed about a third to astronomical causes such as planets and meteors, about a third more to balloons, rockets, flares or birds, and left about a fifth unidentified.
Photo: US Air Force, Public domain
Military1 Oct 1948
North Dakota Air National Guard Lt. George Gorman said he chased a small blinking light in his F-51 over Fargo, which outran him and twice seemed to fly at him. Other observers saw a light. Project Sign investigated, and a January 1949 Air Weather Service study concluded it was a lighted balloon.
Photo: USAF, Public domain
Military7 Jan 1948
Kentucky Air National Guard Capt. Thomas Mantell died when his F-51 crashed while climbing after an object reported by the Godman Field tower near Fort Knox. Investigators concluded he likely lost consciousness from lack of oxygen; a Navy Skyhook balloon is widely cited as the object.
Photo: Kentucky National Guard, Public domain
Military1948
Large plastic Skyhook research balloons, about 100 feet across, were flown in secret for the Navy, unknown to most Air Force pilots. Blue Book chief Edward Ruppelt and the Condon report later cited them as the likely cause of many reports, including Capt. Thomas Mantell's fatal 1948 chase.
Photo: US Navy, Public domain
Military8 Jul 1947
Roswell Army Air Field announced it had recovered a "flying disc" from a nearby ranch, and the Army said the next day it was a weather balloon. A 1994 Air Force report concluded the debris most likely came from Project Mogul, a then-secret balloon program.
Photo: Roswell Daily Record, Public domain
Government8 Jul 1947
An FBI Dallas teletype relayed what Eighth Air Force headquarters told agents about the object recovered near Roswell: a hexagonal object hung from a balloon that resembled a high-altitude weather balloon with a radar reflector, being flown to Wright Field for examination.
Photo: Roswell Daily Record, Public domain
Sightings4 Jul 1947
Off-duty Coast Guard yeoman Frank Ryman photographed what he called a white saucer from his Lake City home in Seattle. Newspapers ran it the next day as one of the first photos of the 1947 wave; analysts later dismissed it as a weather balloon.
Military19 Jul 1946
In summer 1946 Swedes reported hundreds of rocket-like objects; on July 19 witnesses saw one dive into Lake Kolmjarv, but an army search of the lakebed found nothing. A Defence Staff committee attributed many reports to meteors, suspected Soviet tests for the rest, and never found proof.
Photo: Swedish military photo, Public domain
MilitaryJan 1945
An AP story datelined January 1, 1945 reported that U.S. 415th Night Fighter Squadron crews had for weeks seen balls of light pacing their planes over Germany, which they called 'foo-fighters'. TIME followed on January 15; suggested causes ranged from flares to St. Elmo's fire, and none was settled.
Photo: United States Army Air Forces, Public domain
