Why are so many UFOs being reported near nuclear facilities—and why isn’t there more urgency on the part of the government to assess their potential national-security threat?

Those are questions being asked by a team of high-ranking former U.S. defense and intelligence officials, aerospace-industry veterans, academics and others associated with To the Stars Academy of Arts & Science. The team has been investigating a wide range of these sightings—and advocating more serious government attention.

Their investigations are the subject of HISTORY’s limited series “Unidentified.”

Throughout history, unexplained aerial phenomena (UAPs) have shocked, frightened and fascinated sky watchers. And in the last century, more than a few have been reported in military contexts. In late World War II, U.S. airmen called them “foo fighters”: strange orange flying lights by the French-German border. During the Korean War, some soldiers claimed a blue-green light emitting “pulsing rays” made their whole battalion sick with what, to some, resembled radiation poisoning.

Less known: In the last 75 years, high-ranking U.S. military and intelligence personnel have also reported UAPs near sites associated with nuclear power, weaponry and technology—from the early atomic-bomb development and test sites to active nuclear naval fleets.

“All of the nuclear facilities—Los Alamos, Livermore, Sandia, Savannah River—all had dramatic incidents where these unknown craft appeared over the facilities and nobody knew where they were from or what they were doing there,” says investigative journalist George Knapp, who has studied the UAP-nuclear connection for more than 30 years. Knapp has gathered documentation by filing Freedom of Information Act requests to the departments of defense and energy.

“There seems to be a lot of correlation there,” says Lue Elizondo, who from 2007 to 2012 served as director of a covert team of UAP researchers operating inside the Department of Defense. The program, called the Advanced Aerospace Threat Identification Program (AATIP), received $22 million of the Pentagon’s $600 billion budget in 2012, The New York Times reported. Elizondo now helps lead To the Stars’ investigations.

Nuclear-adjacent sightings go back decades, says Robert Hastings, a UFO researcher and author of the book UFOs and Nukes: Extraordinary Encounters at Nuclear Weapons Sites. Hastings says he’s interviewed more than 160 veterans who have witnessed strange things in the skies around nuclear sites.

“You have objects being tracked on radar performing at speeds that no object on earth can perform,” Hastings says. “You have eyewitness [military] personnel. You have jet pilots.” Witnesses to these incidents are often highly trained personnel with top security clearances. In recent years, their reports are being corroborated by sophisticated technology.

In late 1948, “green fireballs” were reported in the skies near atomic laboratories in Los Alamos and Sandia, New Mexico, where the atomic bomb was first developed and tested. A declassified FBI document from 1950 mentions “flying saucers” measuring almost 50 feet in diameter near the Los Alamos labs. And Knapp has interviewed more than a dozen workers from the Nevada desert atomic test site, where scores of A-bombs were detonated in the post-WWII years. He says they told him UFO activity was so commonplace there, employees were assigned to monitor the activity.

In the 1960s and ’70s, repeated UFO sightings emerged at Malmstrom Air Force Base in Montana, a storage site for nuclear-tipped intercontinental ballistic missiles (ICBMs). At one such alleged sighting in 1967, former Air Force Capt. Robert Salas says several of those missiles became inoperative at the same time base security reported seeing a glowing red object, about 30 feet in diameter, hovering over the facility. Salas, who commanded ICBMs as a launch officer and later worked in the aerospace industry and at the Federal Aviation Administration, told CNN the “missiles began going into what's called a ‘no-go condition,’ or unlaunchable.”

Observers can only speculate about the origin of these unexplained phenomena. But the repeated proximity to sensitive defense sites connected to our nation’s most powerful weapons has raised the question of whether they might originate from adversaries—known or unknown.

In late December 1980, air-traffic controllers encountered something alarming near Royal Air Force Bentwaters in England. Used by the U.S. Air Force as a European foothold during the Cold War, Bentwaters housed a secret stash of nuclear weapons in 25 fortified underground bunkers.

“We looked up on the radar scope and saw something…not like anything I’d seen before,” Ivan Barker, a U.S. Air Force air-traffic controller working that night, told HISTORY.com.

Barker, a master sergeant who was second in charge at the facility, says he was an 18-year veteran at that point and knew “about every aircraft in the U.S., NATO and the Soviet bloc.” This object, he says, shocked him and his two colleagues that night with its remarkable speed and maneuverability. On radar, it covered 120 miles in a matter of seconds, he said: “It had to be moving Mach 5, 6, 7 or 8—faster than anything other than possibly a missile.”

As he looked up from the radar to view it directly, the craft moved into close range, slowed and then stopped over the base’s water tower: “Like a helicopter hovering, except with a helicopter you get movement up and down. This was stationary. It was between about 1,500 and 2,000 feet high. The thing was…at least a city block…in diameter.”

Barker says it was shaped like a giant basketball, with portholes around the center, from which lights were emanating outward. “I was shocked… There was nothing aerodynamic about it. Basketballs don’t fly.”

It stopped over the water tower for only a few seconds, he said, before reversing course and speeding back the way it came in: “It was like—swish!—it’s gone.”

Barker didn’t report the sighting to his superiors. “You don’t understand what the Air Force did to people who reported UFOs,” he says.

Barker’s story dovetails with that of Col. Charles Halt, Bentwaters’ deputy commander at the time. Halt led a patrol that night to investigate strange colorful lights seen descending into nearby Rendlesham Forest. Halt described to Elizondo what he saw from inside the forest: a red light moving horizontally though the trees, "obviously under some kind of intelligent control.” A laser-like beam, he said, “landed 10-15 feet away from us. I was literally in shock.”

Then the beam’s source quickly left, flying north toward the base, says Halt, who audiotaped the incident at the time. “We could hear chatter on the radios that the beams went down into the weapons storage area.”

Later, his commander played the audio for a general, who dismissed the need for further investigation. They were loath to get involved, says Halt.

In recent years, sightings of unidentified aerial phenomena have emerged from America’s nuclear navy.

F-18 fighter pilots from the nuclear-powered USS Theodore Roosevelt carrier strike group saw UAPs almost daily for several months between the summer of 2014 and the spring of 2015 while executing training maneuvers along the Eastern seaboard between Virginia and Florida, witnesses told Elizondo.

“Wherever we were, they were there,” says Ryan Graves, an active-duty F-18 fighter pilot from the USS Roosevelt, who holds a degree in aerospace engineering.

The objects appeared in three shapes, Graves says—some were discs, others looked like a cube inside a sphere, while smaller round objects flew together in formation. All lacked visible engines or exhaust systems. Some tilted, mid-flight, like spinning tops, as seen on an infrared video released by the U.S. Department of Defense in 2017. Graves and another F-18 pilot, Danny Accoin, confirm that video, along with one other released by the government, had been shot by their fellow Roosevelt pilots while in the air.

One UAP, Grave says, almost caused a terrifying collision by zipping dangerously between two planes. An aviation flight-safety report was filed, he says, but never investigated.

Graves says the unidentified objects reappeared once the Roosevelt had deployed to its mission in the Persian Gulf.

“It’s hard to find a prosaic explanation for a carrier battle group being shadowed by unidentified aircraft all the way across the Atlantic, to an area of operations overseas in the Middle East,” says Chris Mellon, former U.S. Deputy Assistant Secretary of Defense for Intelligence during the Clinton and George W. Bush administrations, who now serves as an integral part of the To The Stars team. “It makes an extremely compelling case for the existence of technologies we didn’t think were possible.”

Leon Golub, a senior astrophysicist at the Harvard-Smithsonian Center for Astrophysics, told The New York Times there may indeed be several “low-probability” prosaic explanations for the Roosevelt sightings. They include “bugs in the [radar’s] code for the imaging and display systems, atmospheric effects and reflections [and] neurological overload from multiple inputs during high-speed flight.”

Still, the Roosevelt reports echo those made by Navy pilots undergoing training exercises on the other side of the country. In November 2004 pilots and radar operators from the USS Nimitz carrier fleet saw a 40-foot long tic-tac shaped object flying just above the ocean while flying 100 miles off the coast of California near San Diego. When F-18 fighter jets were scrambled to approach the object, it accelerated, easily outrunning the supersonic Navy craft.

Whereas earlier reports were career-killers for military personnel, there is an increasing openness in the Pentagon and on Capitol Hill to taking these sightings seriously as potential threats. In April 2019, the U.S. Navy announced that it was updating its guidelines for how pilots and personnel should report unexplained aerial phenomena—making it easier for military members to report sightings to superiors without facing professional stigma and backlash. And Congress, beginning with former Senate majority leader Harry Reid, has taken more interest in being briefed.

George Knapp says that’s more activity than he has seen in three decades. He, and many others, think it’s overdue.

“At the facilities where we were first designing and building nuclear weapons…at the places where we were processing the fuel…at the facilities where we were testing the weapons…at the bases where we deployed those weapons, on the ships…the nuclear submarines… All those places, all the people working there have seen these things,” Knapp says.

“Are they all crazy?” he continued. “Because if they are, they shouldn't have their hands on nuclear weapons.”