New Mexico, 1948–1950
Beginning in December 1948, brilliant green fireballs appeared repeatedly over America's most sensitive nuclear weapons facilities. The US government launched two secret investigations, brought in the world's leading meteor scientist, and received reports from hundreds of trained observers — including Manhattan Project physicists. After four years and thousands of sightings, the files were classified. No explanation was ever given.
| First sighting | December 1948 — luminous green object observed over Los Alamos National Laboratory |
| Peak activity | January–June 1949 — hundreds of sightings over multiple nuclear installations |
| Government response | Project Twinkle (Dec 1949): network of cameras deployed around New Mexico to track objects |
| Classification | Project Grudge — the classified investigation name, revealed by 2026 PURSUE document release |
| Lead investigator | Dr Lincoln La Paz — University of New Mexico, world authority on meteorite behaviour |
| La Paz conclusion | Not meteors. Trajectory, colour, duration and behaviour all inconsistent with any known natural phenomenon |
| Key document | 116-page Sandia Laboratories general correspondence file, 1948–1950, declassified May 2026 |
| Manhattan Project link | Dr James Tuck and Dr Edward Teller (both bomb designers) personally involved in investigation |
| Soviet parallel | CIA document, 1973: identical green spherical object observed over Sary Shagan nuclear test facility, USSR |
| Final status | Officially unexplained. Investigation wound down 1952. Files classified. No conclusions published. |
In the months after the first Soviet atomic bomb test in August 1949, America's nuclear establishment was on edge. The monopoly had ended. The Cold War was real. And something was flying over the laboratories where the next generation of nuclear weapons was being designed — something that the best scientists in the country could not identify or explain.
The green fireball phenomenon of 1948–1952 is one of the most thoroughly documented and thoroughly suppressed UAP cases in history. It was investigated by the US Army Air Forces, the FBI, the Atomic Energy Commission, and the Air Force's Air Materiel Command. Hundreds of sightings were recorded by trained military and scientific observers. A dedicated surveillance programme was established. And at the end of it all, the files were classified and the investigation was quietly shut down.
The 2026 PURSUE document release, which included a 116-page Sandia Laboratories internal correspondence file and letters from Manhattan Project physicist Dr James Tuck, finally revealed the internal name used for the most sensitive part of this investigation: Project Grudge — a name previously associated only with a public-facing Air Force study designed to discourage UFO reporting. The classified Grudge was something very different.
"They were not meteors. I speak with some confidence on this. No meteor ever flew a level trajectory. No meteor was ever this colour. No meteor ever failed to fragment or leave any recoverable residue."
— Dr Lincoln La Paz, University of New Mexico Institute of MeteoriticsThe first reports arrived in late 1948. Observers at and around Los Alamos National Laboratory — the birthplace of the atomic bomb — began reporting bright green luminous objects moving on flat, controlled trajectories across the New Mexico sky. Unlike meteors, they did not arc downward. Unlike aircraft, they made no sound and moved at speeds that witnesses struggled to estimate. Unlike anything on the classified inventory, they behaved as if under deliberate guidance.
By early 1949, the sightings had multiplied dramatically. The objects were appearing not just over Los Alamos but over Sandia National Laboratories, Kirtland Air Force Base, and the White Sands Missile Range — the four most sensitive nuclear-related installations in the United States, all clustered in central New Mexico. Multiple sightings were occurring per week. The Atomic Energy Commission was notified. The FBI opened a file. The Army Air Forces began collecting reports.
A consistent description emerged across hundreds of independent witness accounts:
A secondary category of sightings, also documented in the Sandia file, described clusters of bright orange orbs — described in the internal correspondence as "countless orange orbs swarming" against mountain backdrops. These appeared less frequently than the green fireballs but were reported by multiple credible observers over the same period.
Green fireball reports begin arriving at Los Alamos and Kirtland AFB. Initial military reports filed. Objects described as unlike any known natural or man-made phenomenon.
Dr Lincoln La Paz, director of UNM Institute of Meteoritics, is engaged by the US military. He conducts systematic interviews with witnesses across New Mexico, eventually speaking to more than 100 people.
A classified conference is held at Los Alamos involving military, FBI, and scientific personnel. Dr Edward Teller and other Manhattan Project physicists attend. The objects are discussed as a potential security concern.
La Paz formally concludes the objects are not meteors. His report is classified. He continues monitoring and investigating through 1950.
The USSR detonates its first atomic bomb (RDS-1), ending America's nuclear monopoly. The security context around the fireball investigation intensifies immediately.
The US Air Force officially establishes Project Twinkle — a network of cinetheodolite cameras positioned around New Mexico specifically to photograph and measure the fireballs in flight. Stations set up at Holloman AFB and other sites.
Sandia Laboratories scientists maintain classified internal correspondence on sightings. This 116-page file, now known from the 2026 PURSUE release, documents the internal scientific response in detail — including the Project Grudge classification.
Camera stations operate across New Mexico. Objects are reportedly detected and tracked on multiple occasions. Results are classified. The data is never released for independent analysis.
Project Twinkle is officially terminated. The final report, eventually partially released under FOIA, concludes inconclusively — attributing some events to atmospheric phenomena while acknowledging others remain unexplained.
Active investigation ceases. Files are classified. No public announcement. No explanation offered. The sightings diminish but do not entirely stop.
The 116-page Sandia general correspondence file is released as part of the US government's PURSUE programme. It confirms the Project Grudge classification, the involvement of Manhattan Project scientists, and the absence of any official explanation.
The world's foremost authority on meteor and meteorite behaviour. Engaged by the US military specifically because of his expertise. After interviewing more than 100 witnesses and analysing all available data, La Paz concluded unambiguously that the objects were not meteors, comets, or any other known natural phenomenon. He privately favoured the hypothesis that they were foreign devices — either Soviet or of unknown origin. He was never able to explain them.
A British-born physicist who worked on the implosion mechanism of the first atomic bomb and later became a senior research figure at Los Alamos. The 2026 PURSUE release revealed his private correspondence from this period, in which he discussed the fireball observations and the difficulty of fitting them into any known physical framework. Tuck appears to have been genuinely troubled by what was being reported around the laboratory.
One of the most formidable theoretical physicists of the 20th century. Teller attended the February 1949 Los Alamos conference on the fireball phenomenon. According to the Tuck correspondence revealed in the 2026 release, Teller suggested the observed objects might not be 'material objects' in the conventional sense — a remark that, whatever its intended meaning, indicates the phenomenon was not being easily dismissed by even the most senior scientific figures.
FBI files from this period show Hoover personally receiving updates on the green fireball sightings near atomic facilities. The Bureau's involvement — treating this as a potential counterintelligence or national security matter — confirms the government's view that the phenomenon was serious. The FBI considered the possibility of Soviet reconnaissance devices.
Scientists and security personnel at Sandia National Laboratories filed numerous internal reports documented in the 116-page PURSUE release. The Sandia observers are notable because these were people with exceptional scientific training working at one of the most secure facilities in the United States — not civilian witnesses prone to misidentification.
"A luminous green spherical object was observed over the [REDACTED] facility. The object appeared to hover at altitude before departing. Duration of observation: approximately [REDACTED] minutes. No conventional explanation identified."— CIA Intelligence Information Report — USSR, 1973 (declassified 2026, via PURSUE)
The 2026 PURSUE release included a CIA intelligence report from 1973 describing an identical phenomenon over the Sary Shagan missile defence test facility in the Soviet Union. Sary Shagan was — and remains — one of the USSR's most sensitive strategic installations, used for testing missile defence systems and anti-satellite weapons.
The CIA document is brief, clinical, and heavily redacted. It describes a luminous green spherical or elliptical object observed hovering at altitude over the facility before departing. The collection method is redacted, as is the precise duration. The report treats the observation as a legitimate intelligence report — the same tone used for reports of Soviet military activity, not the dismissive tone that might accompany a misidentification.
The significance of this document is considerable. The US government spent four years investigating green fireballs over its own nuclear sites and reached no conclusion. Twenty-three years later, an identical phenomenon — same colour, same shape, same association with a nuclear installation — appeared over a Soviet nuclear facility. If the objects of 1948–1952 were Soviet surveillance devices, they would not be appearing over Soviet nuclear sites in 1973. If they were natural phenomena, they would not be so specifically concentrated at nuclear-related installations. Neither explanation survives contact with the 1973 CIA report.
The May 2026 PURSUE release was the first time significant primary documents from the green fireball investigation had entered the public record. Three documents relate directly to this case:
The Sandia Laboratories General Correspondence File (116 pages, 1948–1950) is by far the most significant. This internal file documents the scientific response to the fireball phenomenon from inside one of the most affected institutions. It names the investigation Project Grudge — revealing that the classified investigation shared a name with the public-facing Air Force UFO-debunking study, but was an entirely separate programme with entirely different intent. The file documents hundreds of sightings, the formation patterns observed (T-shapes and triangles are specifically noted), the orange orb secondary phenomenon, and the persistent failure to reach any scientific conclusion. The tone throughout is one of genuine scientific frustration.
The James Tuck Correspondence reveals the personal engagement of Manhattan Project physicists with the phenomenon. Tuck's letters show a man of exceptional scientific standing who was genuinely unable to explain what was being observed around his laboratory. The reference to Edward Teller's remark about "not material objects" is the most striking detail — though its precise meaning remains ambiguous without the full context of the conversation.
The Pajarito Astronomical Society Letter (1986) is the most striking for a different reason: it shows that observations of anomalous luminous phenomena in the Los Alamos area were still being reported by trained observers more than 35 years after the original investigation was closed. The amateur astronomers who wrote to Los Alamos National Laboratory in 1986 were clearly unaware of the classified 1948–1952 investigations — yet they were documenting something recognisably similar.
Military personnel, scientists, FBI agents, and civilian pilots all reported the same phenomena over the same locations. The consistency and credibility of witnesses is exceptional by any standard.
The world authority on meteor behaviour investigated personally and concluded these were not any known natural phenomenon. This conclusion has never been officially overturned.
Project Twinkle camera data, La Paz reports, and Sandia internal correspondence were all classified. The public report was inconclusive. Internal conclusions remain unknown.
CIA intelligence report confirms identical green spherical object over Sary Shagan nuclear facility — 25 years later, on the other side of the Cold War.
The cinetheodolite camera network reportedly detected and tracked objects. The data was classified. It has never been fully released and no independent analysis has been possible.
La Paz's classified reports beyond the initial findings have never been fully released. His complete analysis of more than 100 witness interviews remains in government archives.
Referenced in the James Tuck correspondence but without the full context of the original conversation. Whether this was a serious scientific hypothesis or an offhand remark is unknown.
After four years, two formal investigations, and involvement from the most senior scientific and intelligence figures in the US government, no explanation was ever reached. The official position is that the case is closed. The phenomenon is not explained.
The green fireball incidents are not a marginal chapter in UFO history. They represent one of the most concentrated, best-documented, and most officially serious UAP cases ever recorded. The witnesses were not civilians with no frame of reference — they were the scientists who built the atomic bomb, military personnel responsible for guarding nuclear weapons, and government investigators with the highest security clearances in the country.
The nuclear connection is the thread that makes this case uniquely significant. These objects appeared specifically over nuclear weapons facilities. Not over cities, not over coastlines, not over random stretches of desert — over Los Alamos, over Sandia, over Kirtland, over White Sands. The same phenomenon appeared over a Soviet nuclear test facility in 1973. Whatever these objects were, they appear to have had a specific interest in humanity's nuclear weapons infrastructure at the precise moment in history when that infrastructure first came into existence.
The 2026 PURSUE document release has added important new detail without resolving the core mystery. The Project Grudge classification confirms that the most sensitive parts of the investigation were deliberately separated from the public-facing Air Force study. The Tuck correspondence shows the personal engagement of bomb designers. The 1973 CIA report extends the pattern into the Soviet Union. And the 1986 Pajarito letter shows the phenomenon had not gone away.
The green fireballs of New Mexico were never explained. After more than 75 years, they remain one of the most credible and most overlooked UAP cases on record.
"If these objects are not meteors — and I am confident they are not meteors — then we are dealing with something that our current framework of knowledge cannot accommodate."
— Dr Lincoln La Paz, 1949 (paraphrased from classified report — full text remains unreleased)