Project Heavy Green and Lima Site 85

August 1, 1966 - August 31, 1966

Overview

Under the code name Project Heavy Green, the CIA—with U.S. Air Force assistance—establishes a tactical air navigation station on Phou Pha Thi mountain, at Lima Site 85, in Laos. Phou Pha Thi has steep cliffs on three sides making it difficult to reach the summit except by helicopter. The station at the summit is kept secret because Laos is officially neutral.

From Lima Site 85, U.S. Air Force personnel, posing as civilian employees of Lockheed Aircraft, use Combat Skyspot radar to guide accurate bombing of North Vietnam and northern Laos. Many of the strikes take place in the Red River Delta and the Hanoi areas, which are about 150 miles away from the station.¹

¹Timothy Castle, One Day Too Long (New York: Columbia University Press, 1999), 38, 43-45, 59-63; Carl Berger, ed. The United States Air Force in Southeast Asia: An Illustrated Account (Washington, D.C.: Office of Air Force History, 1977), 126; Spencer C. Tucker, ed. The Encyclopedia of the Vietnam War: A Political, Social, and Military History, (2nd edition; Santa Barbara, CA: ABC-CLIO, 2011), 657–658; “The Fall of Lima Site 85: The War in Laos,” https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/95unclass/Linder.html (link is external) (accessed 7/22/14).