US Military Begins Operation Popeye, a Cloud Seeding Program
Project Popeye was an experiment in increased rainfall through cloud seeding jointly approved by the U.S. Department of State and U.S. Department of Defense.
The technical aspects of the experiment were verified by Dr. Donald F. Hornig, Special Assistant to the President of the United States for Science and Technology. The government of Laos was not informed of the project, its methods or its goals.
Robert S. McNamara, U.S. Secretary of Defense, was aware that there might be objections raised by the international scientific community but said in a memo to the president that such objections had not in the past been a basis for prevention of military activities considered to be in the interests of U.S. national security.
During October 1966, Project Popeye was tested in a strip of the Laos panhandle east of the Bolovens Plateau in the Se Kong River valley. The test was conducted by personnel from the Naval Ordnance Test Station located at China Lake California. Fifty cloud seeding experiments were conducted with the result that 82% of the clouds produced rain within a brief period after having been seeded. It was claimed that one of the clouds drifted across the Vietnam border and dropped nine inches of rain on a US special forces camp over a four hour period. After the successful completion of the test phase, Project Popeye transitioned from an experiment to an operational program of the U.S. Defense department.
Operation Popeye first came to public light in March 1971, when reporter Jack Anderson published a story based on a secret 1967 memo from the Joint Chiefs of Staff to President Johnson. The memo read: "Laos operations - Continue as at present plus Pop Eye to reduce the trafficability [sic] along infiltration routes & Authorization requested to implement operational phase of weather modification process previously successful tested and evaluated in some area". (US Senate, Subcommittee on Oceans and International Environment; 26 July 1972; p. 5).