Investigation of UFO reports by the United States government

UFO investigations by the United States
Time period	1947–present
Historical precedents	Mystery airships; Ghost rockets; Kenneth Arnold sighting; 1947 UFO craze;
Project or team leaders	Edward Ruppelt (Blue Book); Hector Quintanilla (Blue Book); Edward Condon (Condon Committee); David Spergel (NASA's UAP team); Sean Kirkpatrick (AARO);
Key events	1947 Air Force order issued to start UFO study; 1948 Project Sign; 1949 Project Grudge (replaced Sign); 1952–1969 Project Blue Book (replaced Grudge); 1953 Robertson Panel; 1966 Congressional hearing on UFOs; 1968 Condon Committee; 1969 Congressional hearing on UFOs; 1994–1997 Air Force releases official reports on the Roswell incident; 2007–2017 AATIP (dates disputed); 2017–2022 UAPTF (replaced AATIP); 2022 Congressional hearing on UAPs; 2002–present NASA's UAP study team; 2002–present AARO (replaced UAPTF); 2023 Congressional hearing on UAPs;
Websites	www.aaro.mil; science.nasa.gov/uap;

Investigation and analysis of reported UFO incidents under the federal government of the United States has taken place under multiple branches and agencies, past and current, since 1947. In spite of decades of interest, there remains no evidence that there are any purported UFOs with extraordinary provenance and, indeed, those identified all have been shown to be natural phenomena, human technology, misapprehensions, delusions, or hoaxes.

The first programs were established under the U.S. Air Force between 1947 and 1969 with Project Sign, Project Grudge, and finally Project Blue Book. The Condon Report in 1968 led the U.S. to stop spending resources on the effort to receive and analyze UFO reports because "nothing has come from the study of UFOs in the past 21 years that has added to scientific knowledge" and "further extensive study of UFOs probably cannot be justified".

In 2017 The New York Times revealed that $22 million had been spent over the past ten years on an unpublicized Advanced Aerospace Threat Identification Program (AATIP) funded by the U.S. Congress. The story also referenced two videos recorded by the U.S. Navy of what officials referred to as "unidentified aerial phenomena", or UAP. In 2020, the Pentagon later released three videos from Navy jets that showed unusual observations and confirmed the provenance of some leaked 2019 videos in two statements made during 2021.

From 2017 to 2020, the Unidentified Aerial Phenomena Task Force (UAPTF) was set up as a program within the Office of Naval Intelligence to "standardize collection and reporting" of sightings of UFOs. On May 17, 2022, members of the U.S. House Intelligence Subcommittee held congressional hearings with top military officials to discuss military reports of UAPs. This was the first public congressional hearing into UFO sightings in the U.S. in over 50 years. In June 2022, plans were announced by NASA to assemble an independent study team. In July 2022, UAPTF was succeeded by the All-domain Anomaly Resolution Office (AARO). The participants of NASA's study team were announced in October 2022. The first public meeting of the NASA team was held on May 31, 2023.