Lundahl provided critical intelligence on the arms race and many other international crises, including the Suez Crisis; Quemoy and Matsu, islands controlled by Taiwan; Tibet; Lebanon, and Laos.

Early in his career, he combined his academic training as a geologist with his hobby as a photographer, and became expert in interpreting details of pictures and distinguishing natural features from manmade construction.

He developed his new skills during World War II while serving in the Navy, studying aerial photographs of targets in Japan and the Aleutian and Kuril islands.

In 1953, he moved to the CIA, to lead the "Photographic Interpretation Division (PID), manage both general photointerpretation and then the products, in the late fifties, of the U-2 program.

In that effort, he combined photo interpretation, automatic data processing, photogrammetry, graphic arts, communications, collateral research, and technical analysis into the NPIC.

According to his associate, Dino Brugioni, on July 4, 1956, using the U-2 aircraft, and within two months, the NPIC could put to rest the political accusation of a "bomber gap".

BG Edward B. Giller, USAF, was the contract monitor, Dr. Thomas Rachford was the senior Air Force Scientist on the project, and the principal investigator from the University was Dr. E.U.

The committee was again impressed with the technical work performed, and Condon remarked that for the first time a scientific analysis of a UFO would stand up to investigation.

On an episode of The Joe Rogan Experience podcast, computer scientist Jacque Vallée recounted a conversation he had with Lundahl about a piece of strange metal which had been shot off an UFO during a 1952 sighting over Washington, D.C. Lundahl gathered the NPIC staff on August 19, 1960, to show them the images from the first photoreconnaissance satellite, Discoverer 14, to fly with its camera.

[5]" U-2 photographs taken on [6] October 14, 1962, in which analysts, under Lundahl's direction, found visual evidence of the placement of Soviet SS-4 medium-range ballistic missiles (MRBM), capable of hitting targets, in the continental United States, with nuclear warheads.

His briefing of John F. Kennedy, on October 16, confirmed the Soviet weapons' presence, which had not been expected by the intelligence community or military .

[7] Lundahl began the briefing, with assistance from Acting Director of Central Intelligence whose voice is low and often difficult to hear.

[8] After receiving a report from the Panel for Future Satellite Reconnaissance Operations, whose members included Edward Purcell, the chairman, Richard Garwin, Edwin Land, and NPIC director Arthur Lundahl, the CIA Directorate of Science and Technology directed Itek Corporation to stop work on the M-2 follow on to the CORONA satellite and concentrate on improving CORONA.

[11] Lundahl appears in Thirteen Days: A Memoir of the Cuban Missile Crisis, by Robert F. Kennedy (1969), and was portrayed by Dakin Matthews in the 2000 film adaptation.