Operation Redwing

Operation Redwing was a United States series of 17 nuclear test detonations from May to July 1956. They were conducted at Bikini and Enewetak atolls. The entire operation followed Operation Wigwam and preceded Operation Plumbbob. The primary intention was to test new, second-generation thermonuclear devices. Also tested were fission devices intended to be used as primaries for thermonuclear weapons, and small tactical weapons for air defense. Redwing demonstrated the first US airdrop of a deliverable hydrogen bomb - test "Cherokee". Because the yields for many tests at Operation Castle in 1954 were dramatically higher than predictions, Redwing was conducted using an "energy budget" - there were limits to the total amount of energy released, and the amount of fission yield was also strictly controlled. Fission, primarily "fast" fission of the natural uranium tamper surrounding the fusion capsule, greatly increases the yield of thermonuclear devices, and contributes the vast majority of the fallout - fusion being a relatively clean reaction.

All shots were named after various US Native American tribes.

Michael Harris, a former public relations executive at CBS, served in the U.S. Army on Enewetak Atoll during most of Operation Redwing. He wrote about his experiences in The Atomic Times: My H-Bomb Year at the Pacific Proving Ground (Random House, 2005). To protect privacy, he changed most of the names of his fellow soldiers. According to Harris in The Atomic Times, soldiers on Enewetak experienced fallout from eight blasts: 1) Zuni (3.5 megatons, Bikini) and Yuma (0.19 kilotons, Enewetak), both detonated on May 28, 1956;  2) Seminole, a 13.7 kiloton surface burst exploded inside a water tank on June 6, 1956; 3) Blackfoot (8 kilotons, Enewetak) and Flathead (365 kilotons, Bikini), another double shot day on June 12, 1956; 4) Inca (15.2 kilotons, Enewetak) on June 22, 1956; 5) Apache (1.85 megatons, Enewetak) on July 9, 1956; and 6) and Tewa (5 megatons, Bikini) on July 21, 1956, the “dirtiest shot ever,” according to Harris, with Enewetak being hit with “very heavy” fallout that lasted for days.

Harris personally experienced the Redwing Lacrosse through Redwing Dakota detonations, noting that the much smaller-yield explosions at Enewetak appeared to be the same size as the much larger explosions more than 150 miles away at Bikini. He left the atoll and was honorably discharged before the final five test shots, and therefore missed the most powerful detonations at Enewetak.

Tests
The following tests all took place in 1956. The dates are in local time, followed by the yield.