High Altitude Tests

edit

These tests were designed to study many effects that a nuclear explosion would have on materials and electronic systems. They were also used to test the energy of the explosion and what forms of energy they would produce. All of the high altitude tests were done in the South Pacific Ocean about 1,300 kilometers south east of the Hawaiian Islands.[1]

YUCCA

edit

Yucca was the first high altitude test done during Operation Hardtack on April 28, 1958 and had a yield of 1.7 kilotons.[1][2] To achieve the altitude needed for detonation the device was attached to a large helium filled balloon which would carry it to the detonation altitude. Due to issues with high winds on Enewetak Island the balloon launches from ground were unsatisfactory thus creating the need for a new method to be developed.[3] The balloons were then deployed from an aircraft carrier which helped not only with deployment but also with inflation. While the balloons were inflated they were unable to take too much force from wind or the plastic material the balloons were made of would tear. While the balloons were inflating on the aircraft carrier, the ship could match and oppose the wind speed allowing for the balloon to be inflated in still air. To make sure the launch would be successful 86 balloon launches were tested.[3]

Due to concerns of failures many safety measurements were put into place. While on ground the bomb used multiple pins to keep certain safety features of the bomb from being deployed before liftoff could take place. One such pin was used to stop the electrical systems such that the bomb would be unable to be armed. In case of a dud the bomb would detach from the balloon and be allowed to drop into the ocean where many more safety features would come into action. Some of these features included probes which could detect saltwater which would destroy the electrical system so the conductive seawater could not cause a short which would detonate the bomb. Another worry was having a nuclear device floating in the ocean if a misfire did occur. To combat this inserts were created which would dissolve over a course of a few hours which would sink the device.[4]

On the day of the launch many meteorological aspects were taken into account and calculations were done to make sure the bomb would reach its correct altitude. The bomb was loaded onto an aircraft carrier and preparations began for the test fire. As the balloon was inflated on the aircraft carrier multiple testing devices were connected to the balloon. The readings from these devices would be sent to multiple ships and aircraft so nothing would have to be recovered after the explosion.[5] After all the preparations were done and the balloon was inflated the device was released and began to climb. After almost three and a half hours of climbing the bomb was detonated at an altitude of 26.2 kilometers. The aircraft carrier which carried Yucca was around 45 kilometers from the detonation site when the explosion occurred. The shock wave from Yucca reached the carrier 3 minutes and 16 seconds after detonation.[6]

The Yucca test had many Department of Defense projects attached to it for research purposes. Alongside testing the use of a balloon carrier the Department of Defense wanted to research the electromagnetic waves emitted from a nuclear explosion. This test would be used to see the impact a nuclear explosion would have on electronic devices. All of the data from these Department of Defense projects would be stored on recording devices on surrounding islands and in aircraft so data would not have to be recovered after the test.[4] However, Yucca was carrying five different transmitting devices in canisters to help with research. While the balloon proved to be a great success no data from the canisters was able to be received due to equipment issues on board one of the aircraft carriers.[7]

TEAK

edit

The Teak test was launched from Johnston Island on the 31st of July 1958 and carried a payload of 3.8 megatons.[1][8] Teak was the second high altitude test after the success of Yucca. In the stead of a balloon, the warhead for the Teak test would be carried by a missile. The Redstone missile which would carry Teak had been used to launch Explorer I in January of the same year.[6] Other nuclear weapons had been tested using the Redstone missile but up until this point the highest payload to have been detonated was 3 kilotons during Operation Teapot.[9] Teak would be the first high altitude test to have a payload in the megaton range. The test was scheduled to take place from the Bikini Atoll. However, due to the fact that the payloads of Teak and Orange were much larger than previous high altitude shots the test was moved to Johnston Island as to protect nearby native islanders from any retinal damage. As both Teak and Orange had been relocated these two tests would be known as Operation Newsreel. The name Newsreel came from the fact that these two test were being moved to Johnston Island.[10]

The safety precautions taken by the teams involved in these tests were precisely detailed. The day before the launch 187 team members would evacuate Johnston Island with 727 men the day of the test. This was to keep as few men on the island while still being able to operate the airfield and critical data instruments.[11] Another problem the team members were concerned about was the issue of retinal damage. Since the payload of the bomb was so large aircraft were scheduled to keep any civilian ships out of a 760 kilometer radius of Johnston Island. Additionally the Civil Aeronautics Authority was informed that it would be dangerous for any aircraft to fly within 965 kilometers of Johnston Island. On the day of the test only about 175 men remained on Johnston Island to prepare for Teak to be launched and other various duties needed after.[12]

At 11:47 PM on July 31st Teak was launched and after 3 minutes was detonated. Due to program issues the missile launched directly above Johnston Island.[13] At time of detonation the rocket had flown to an altitude of 76.2 kilometers. The explosion could be seen from Hawaii 1,297 kilometers away and was said to be visible for almost half an hour. After the explosion high frequency long distance communication in Australia and Hawaii was disrupted. Due to this communication failure Johnston Island was unable to contact the superior in the states to let them know how the test had gone until about eight hours after the detonation. Thirty minutes after detonation a crew was sent out to collect the pod that carried the warhead which had detached. The pod had been irradiated and to handle it the crew members used disposable gloves as to protect themselves from beta radiation.[14]

During the Teak test all crew on and around Johnston Island were given protective eye wear to stop flash blindness once the explosion took place. After the explosion it was found that besides the hazard of blindness, thermal radiation was another concern even at an altitude of 76 kilometers. A crew member who was on Johnston Island at the time was said to have received a slight sunburn from the amount of thermal radiation which had reached the island. While only slight to the crew member this created issues for the local fauna. Many birds were seen on Johnston Island in distress. Unsure if this was caused by blindness or thermal radiation the project members decided to take precautions to protect local wildlife during the Orange test.[15]

ORANGE

edit

Orange was launched twelve days after Teak on August 11th 1958.[1] Orange, like Teak, was launched using a Redstone Missile and had a yield of 3.8 megatons.[8] The same safety precautions used by Teak were implemented again for the Orange launch. Seeing how smoothly the evacuation for the Teak launch went it was decided that the evacuation did not need to occur the day before the launch and eight hundred and eight men were evacuated on August 11th to an aircraft carrier about 70 kilometers northeast of the island. Along with protection for the project crew, it was decided after Teak that Sand Island, a local bird refuge, would need protection from the blast as well. To make sure that most of the wildlife was safe a smoke screen was created over Sand Island. Due to interest in Hawaii it was announced on August 11th that there would be a nuclear test sometime between 10 PM and 6 AM.[16]

The rocket carrying the warhead was launched at 11:27 from Johnston Island and traveled south. Like Teak, the flight lasted 3 minutes and was detonated at 11:30 PM about 41 kilometers south of Johnston Island at an altitude of about 43 kilometers.[16] The trajectory of Orange was a major success after the incident with Teak being detonated directly over the island.[13] The recovery crew for the pod that was with Orange was unable to locate the research pod which had been launched with the rocket. Although Orange was visible from Hawaii it was not as great of a spectacle as Teak had been. The light from the blast was only visible for about 5 minutes. The explosion had also been slightly obscured to the crew at Johnston Island from cloud coverage that night. The blast from Orange did not come with large communication interruption that Teak had caused. Although some commercial flights to Hawaii were said to have lost contact with air traffic controllers for a short period of time.[16]

Concern for Ozone Layer

edit

There was some uncertainty on whether detonating a nuclear weapon at such high altitudes would cause a hole in the ozone layer. After multiple underwater tests there was evidence to show the energy created by the blast would create ozone. Project leads determined some destruction of ozone would occur which would then be replaced by the ozone created from the explosion, it was agreed upon that if this theory were wrong the hole created in the ozone layer would be minuscule enough to cause no harm. After both Teak and Orange there was found to be very little evidence of any harm caused to the natural ozone layer.[15]

  1. ^ a b c d Operation Hardtack I, 1958, DNA6038F, ADA136819 page 251[1]
  2. ^ Operation Hardtack 1 Fact Sheet, Defense Threat Reduction Agency, page 2 accessed 4-19-2016[2]
  3. ^ a b Operation Hardtack I, 1958, DNA6038F, ADA136819 page 252[3]
  4. ^ a b Operation Hardtack I, 1958, DNA6038F, ADA136819 pages 253-254[4]
  5. ^ Operation Hardtack I, 1958, DNA6038F, ADA136819 page 255[5]
  6. ^ a b Operation Hardtack I, 1958, DNA6038F, ADA136819 pages 256-257[6]
  7. ^ Operation Hardtack Preliminary Report, 1959, ITR-1660-(SAN), ADA369152 page 201[7]
  8. ^ a b Operation Hardtack 1 Fact Sheet, Defense Threat Reduction Agency, page 3 accessed 4-19-2016[8]
  9. ^ Operation Hardtack Preliminary Report, 1959, ITR-1660-(SAN), ADA369152 page 218[9]
  10. ^ Operation Hardtack I, 1958, DNA6038F, ADA136819 page 259[10]
  11. ^ Operation Hardtack I, 1958, DNA6038F, ADA136819 page 263[11]
  12. ^ Operation Hardtack I, 1958, DNA6038F, ADA136819 pages 262-263[12]
  13. ^ a b Operation Hardtack Preliminary Report, 1959, ITR-1660-(SAN), ADA369152 page 219[13]
  14. ^ Operation Hardtack I, 1958, DNA6038F, ADA136819 pages 265-270[14]
  15. ^ a b Hoerlin, Herman United States High-Altitude Test Experiences: A Review Emphasizing the Impact on the Environment Report LA-6405, Los Alamos Scientific Laboratory. October 1976
  16. ^ a b c Operation Hardtack I, 1958, DNA6038F, ADA136819 page 271[15]