197. Editorial Note
AEC Chairman Seaborg wrote President Johnson on June 2, 1967, requesting approval of Crosstie, the FY 1968 underground nuclear weapons testing program. (Seaborg, Journal, Volume 14, page 688) At a June 20 meeting of the Annual Briefing of the 307 Committee (Review Committee for Underground Nuclear Testing), Seaborg and other AEC members presented the Crosstie program which consisted of 48 tests, including 2 nuclear excavation tests, Cabriolet and Buggy I. (Ibid., page 772)
President Johnson indicated his approval of Crosstie on a June 30 memorandum from Walt Rostow. However, the two nuclear excavation tests were not granted specific approval and thus were not included in the first quarter authorization. (Johnson Library, National Security File, Subject File, Nuclear Testing-U.S. Testing Program FY 1968, Volume VI, Box 28) On July 3, Seaborg wrote Rostow that substitutions had been made in Crosstie I, the first quarter test program. (Department of State, S/S-RD Files: Lot 71 D 171)
On July 6, Rostow sent a memorandum to Seaborg informing him that President Johnson had approved Crosstie and Crosstie I, but that specific approval would be required for “cratering experiments or tests to be executed outside the continental United States.” (Johnson Library, National Security File, Subject File, Nuclear Testing-U.S. Testing Program FY 1968, Volume VI, Box 28) Crosstie I consisted of 11 AEC weapon development tests, 1 AEC test for peaceful applications, and 1 Department of Defense weapons effects test. All tests took place at the Nevada Test Site. (United States Nuclear Tests, July 1945 Through September 1992, page 30)
In a September 15 letter to President Johnson, Seaborg requested Presidential approval of 15 tests in the second quarter test program, Crosstie II. (Johnson Library, National Security File, Memoranda to the President, Walt Rostow, Volume 44, Box 23) An October 10 entry in Seaborg’s Journal reveals that Rostow sent Seaborg a memorandum indicating Presidential approval of Crosstie II. (Seaborg, Journal, Volume 15, page 377) This memorandum, however, has not been further identified. A total of eight nuclear weapons tests were conducted under Crosstie II, including Gasbuggy, a Plowshare test, which was tested at Farmington, New Mexico; the remaining tests were conducted at the Nevada Test Site. (United States Nuclear Tests, July 1945 Through September 1992, page 30)
A request for approval of Crosstie III was forwarded to President Johnson in a December 22 letter from Seaborg. Crosstie III consisted of 18 tests including 6 deferred from Crosstie II due to “programmatic and technical difficulties.” Specific requests for approval of Cabriolet and Buggy I, the two Plowshare cratering experiments, were not included in [Page 481] Seaborg’s letter. (Johnson Library, National Security File, Subject File, Nuclear Testing-U.S. Testing Program FY 1968, Volume VI, Box 28) President Johnson indicated his approval of Crosstie III on a January 5, 1968, memorandum from Walt Rostow. Sixteen tests were approved including Cabriolet; authorization for Buggy I continued to be handled as a separate matter. (Ibid.) A total of 14 nuclear tests were executed, including Cabriolet and Buggy I. All tests took place at the Nevada Test Site, except for Faultless which was conducted in Central Nevada. (United States Nuclear Tests, July 1945 Through September 1992, pages 31-32)
The Crosstie IV program consisted of 19 proposed tests including 2 Department of Defense weapons effects tests to be conducted in the fourth quarter of FY 1968. Seaborg requested authorization for this program in a March 13 letter to President Johnson. (Johnson Library, National Security Policy, Subject File, Nuclear Testing Program FY 1968, Volume VI, Box 28) In a March 25 memorandum from Rostow to the President, Rostow requested the President’s approval of Crosstie IV. The President approved Crosstie IV on March 26, and Rostow wrote Seaborg on the same date relaying Presidential approval. (Ibid.) A total of 15 tests, all conducted at the Nevada Test Site, took place. (United States Nuclear Tests, July 1945 Through September 1992, pages 32-33)
A summary history of this test series is U.S. Defense Nuclear Agency, Operations Crosstie and Bowline: Events—Door Mist, Dorsal Fin, Milk Shake, Diana Moon, Hudson Seal, and Ming Vase, 31 August 1967-20 November 1968 (DNA 6322F, 1985).