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Operation Crossroads

  • Nagasaki Bomb Detonation

    Nagasaki Bomb Detonation

    • Bomb detonation occurred 9, 1945
    • Operation Crossroads was the first nuclear test since Operation Trinity in July of 1945.
    • First nuclear device detonation since Nagasaki.
  • Proposal to test nuclear weapons against warships

    Proposal to test nuclear weapons against warships

    • Proposed by Lewis Strauss, future chairman of the Atomic Energy Commission
    • Designed to demonstrate the vulberability, rather than survivability of ships
    • Largely for public opinion to prove that the fleet was not obsolete in the face of this new weapon
  • Determining Test Location

    Determining Test Location

    Location Stipulations:
    - Site must be controlled by US
    - Inhabitants would have to be evacuated (preferably uninhabited)
    - Must be at least 300 miles from the nearest city
    - Airbase had to be within 1,000 miles for B-29 bomber
    - Protected anchorage of at least 6 miles for target ships
    Ideally predictable weather patterns (free of severe cold/violent storms) wind and ocean patterns to avoid blow back to personnel and protect shipping lanes.
  • Truman appoints Vice Admiral William Blandy to Lead Test

    Truman appoints Vice Admiral William Blandy to Lead Test

    • Since the US Navy contributed most men and material, test should be headed by a naval officer.
    • Commodore William Parsons was originally considered for involvement in the Manhattan project
    • Parsons was now Deputy Chief of Naval Operations for Special Weapons. He recommended Blandy.
  • US declares control of Pacific Islands Captured

    US declares control of Pacific Islands Captured

    • Truman declares "US to be sole trustee of all the pacific islands captured from Japan during war
    • Of the pacific islands, Marshall Islands were included with intention of conducting nuclear tests
    • US government studying site since October 1945
  • Bikini Lagoon Named as Test Site

    Bikini Lagoon Named as Test Site

    • Two detonation test scheduled for 1946: Able and Baker with underwater Charlie scheduled for 1947
    - Bikini offered most remote location, large protected anchorage, suitable weather, small and easily moved population.
  • Clearing a Path

    Clearing a Path

    • Survey Ship Sumner began blasting channels through Bikini reef into lagoon, residents had no idea why.
    • 167 Bikini islanders were relocated
    • Biblical stories were used comparing them to "children of Israel whom the Lord saved and led to promised land."
    • In 1960 natives returned only to be told a decade later that returnees had a 75% increase in levels of Cesium-137.
    • 80-100 US surplus ships, and approx. 60 Japan and German captured ships used as targets
  • Able Radiation

    Able Radiation

    • Same as Little boy & Fat Man (Nagasaki), Able was an air burst to avoid surface materials from being drawn into fireball
    • Intense burst of fireball radiation lasting a few seconds, closest ships to blast received neutron and gamma radiation lethal to anyone onboard
    • One sailor on a support ship took a souvenir only to be told that he'd be "sleeping in a shower of gamma rays"
    • 57 guinea pigs, 109 mice, 146 pigs, 176 goats, 3,030 white rats placed on 22 target ships. 10% killed in blast
  • Test Able

    Test Able

    • Delivery via free fall air drop 518 ft by Mk III Gilda device with a yield of 23 kt (kilotons)
    • Remote auto piloted B-17 were outfitted with cameras, radiation detectors, and air sample collectors allowing the drones to fly into Able's mushroom cloud.
    • 114 press observed explosion (first time a test was announced before hand and press allowed to attend) some expressed disappointment in the less-than-expected damage
    • Bomb missed aim point by 710 yards, reason never found.
    • Target USS Nevada
  • Test Baker

    Test Baker

    • Baker detonated 90 feet underwater
    • Target ship LSM-60 vaporized by nuclear fireball, 10 ships sunk including German Heavy cruiser
    • Greatest difference between two tests were radioactive contamination of all target ships by Baker due to water pressure vs air pressure.
    • Only 9 surviving Baker target ships were eventually decontaminated and sold for scrap.
    • Baker was the first nuclear explosion close enough to the surface to keep radioactive fission products in the local environment.
  • Baker Fallout

    Baker Fallout

    • Baker produced so many unusual phenomena that a conference was held two months later to standardize new terms for descriptive analysis.
    • Baker produced 3lbs of fission products, thoroughly mixed with two million tons of spray and seabed sand in its cauliflower head and then dumped back into the lagoon.
    • Onboard instruments allowed remote-controlled radiation measurements, drone boats detected radiation hotspots
    • Personnel radiation exposure similar to Manhattan project 0.1 roentgens per day
  • America's First H-bomb

    America's First H-bomb

    • 3rd test (Charlie) was cancelled due to lack of resources and focus on creating smaller, lighter atomic weapon
    • 23,500 lb device (shrimp) produced 15-megaton blast (3x bigger than planned) -Vaporized 3 islands, tore mile-wide crater in bottom of lagoon
    • bomb blast hurled debris into air equivalent of 216 empire state buildings
    • radioactive bomb debris contaminated 23 Japanese fishing crew members 80 miles away.
  • Pop Culture

    Pop Culture

    • Sponge Bob & Godzilla
  • Declassified Videos

    Declassified Videos

    • Footage declassified in 2016 and available for public viewing Test Footage