UAP Reported at Sandia Base, 1948–1950 — Department of War File
This file contains 116 pages of documentation from the Armed Forces Special Weapons Program (AFSWP) – the direct, post-World War II successor to the Manhattan Project – and from the U.S. Air Force – relating to a series of sightings and investigations in Sandia, New Mexico, from 1948-1950. This…
Incident Overview
Sandia Base, adjacent to Kirtland Army Air Field on the southern edge of Albuquerque, was in 1948 one of the most sensitive facilities in the United States. It was the primary nuclear weapons assembly site operated by the Armed Forces Special Weapons Program (AFSWP) — the direct successor to the Manhattan Project, established in 1947 to manage America’s nuclear arsenal as it transitioned from wartime to Cold War standing. The scientists and engineers at Sandia were assembling, modifying, and studying nuclear warheads. What they began reporting in 1948, and kept reporting through 1950, was something none of their security protocols had prepared them for: bright green fireballs, luminous discs, and orbs appearing repeatedly in the skies above and around the base.
The 116-page file released by the Department of War is the formal paper trail of that experience. It contains 209 documented sightings — not anecdotes, but official reports filed by military personnel and civilian scientists at one of the most security-conscious installations in the country. The phenomena they described were strikingly consistent: green orbs moving at unusual speeds, discs maneuvering in ways that didn’t match known aircraft, fireballs that appeared to explode without leaving debris. Witnesses reported UAP flying out of sight at speeds they couldn’t estimate, disappearing without explanation, and in some cases apparently reacting to observation.
What elevated the Sandia sightings beyond routine UFO reports of the era was the physical evidence. Investigators recovered what they described as residual copper powder in areas where sightings had been concentrated. The Army Air Force tasked formal investigation teams to analyze the material and attempt to correlate it with the aerial observations. No conclusive link was established, but the copper residue findings meant the Sandia case file crossed from witness testimony into physical trace evidence — a threshold that drove sustained official attention.
The sightings at Sandia occurred in parallel with nearly identical reports from Los Alamos, White Sands Missile Range, and Oak Ridge, Tennessee — the other nodes of America’s nuclear weapons complex. Dr. Lincoln LaPaz, a University of New Mexico astronomer who specialized in meteoritics, was retained by the military to study the green fireball phenomenon specifically. LaPaz concluded the green fireballs were not natural meteors: their flat trajectories, consistent coloring, and controlled-seeming behavior distinguished them from any known astronomical phenomenon. His conclusions, which he maintained for decades, contributed directly to the establishment of Project Twinkle in 1950, a formal Air Force scientific investigation into the fireballs that operated concurrently with the later stages of the Sandia documentation period.
Some of the Sandia investigations were also folded into Project Grudge, the Air Force’s UFO investigation program that ran from 1949 to 1951 and collected reports from military installations across the country. The Sandia base file thus sits at the root of the formal American military UFO investigation infrastructure: it is one of the source documents that made institutionalized UAP reporting a feature of the postwar national security apparatus. The Department of War’s decision to include it in the PURSUE presidential disclosure is recognition that what was happening at Sandia in the early nuclear age was not resolved then, and remains unresolved now. The Sandia file is the oldest anchor of a four-decade thread of UAP records from the American nuclear weapons complex that runs through the declassified corpus.
What the government released
This file contains 116 pages of documentation from the Armed Forces Special Weapons Program (AFSWP) – the direct, post-World War II successor to the Manhattan Project – and from the U.S. Air Force – relating to a series of sightings and investigations in Sandia, New Mexico, from 1948-1950. This file contains 209 sightings of “green orbs,” “discs,” and “fireballs” reported near the military base. Witnesses reported unidentified anomalous phenomena (UAP) maneuvering, flying out of sight, disappearing, or exploding. The documents also include the results of contemporary investigations into residual copper powder found in some areas where sightings were reported. A few of these investigations became the basis for Project Grudge, which collected reports of unidentified flying objects from various other military installations – also included in this collection.
Status of the case
Records released under the PURSUE program are designated unresolved by the All-domain Anomaly Resolution Office, which means the federal government has not concluded the events were anomalous, has not concluded they were conventional, and has not ruled out either possibility. Where AARO has offered a likely source for an item — an infrared sensor aboard a military aircraft, a commercial camera, or a known optical effect — that attribution is the agency’s working assessment rather than a final determination. Conventional candidates such as drones, balloons, flares, satellites, parallax and forced-perspective artifacts, and ordinary aircraft remain on the table for any unresolved case absent better data than a single sensor pass or a witness recollection.