Starfish Prime was a nuclear test in the upper atmosphere carried out by the United States. It was a joint project between the Atomic Energy Commission (AEC) and the Defense Atomic Support Agency. The test took place on July 9, 1962, from Johnston Atoll, a location in the Pacific Ocean about 900 miles (1,450 km) west-southwest of Hawaii. It was the largest nuclear test the United States conducted in space and one of five such tests performed by the country.
A Thor rocket carrying a powerful nuclear weapon called the W49 thermonuclear warhead (developed at Los Alamos Scientific Laboratory) and a Mk. 2 reentry vehicle was launched from Johnston Atoll. The explosion occurred at an altitude of 250 miles (400 km), above a point 19 miles (31 km) southwest of the atoll. The test had a yield of 1.4 megatons (5.9 petajoules). From Hawaii, the explosion was visible about 10 degrees above the horizon at 11:00 p.m. local time.
Operation Fishbowl
The Starfish test was one of five high-altitude tests that were part of a group called Operation Fishbowl. This group was part of a larger project named Operation Dominic. These tests happened in 1962 and were started because the Soviet Union announced on August 30, 1961, that they would stop a three-year period when they had not done any testing.
In 1958, the United States finished six high-altitude nuclear tests. These tests led to many unexpected results and created many new questions. According to the U.S. Government Project Officer's Interim Report on the Starfish Prime project:
Earlier high-altitude nuclear tests, including YUCCA, TEAK, ORANGE, and the three ARGUS tests, were not well measured and done quickly without enough care. Even though experts studied the limited data carefully, the models they made of these tests are not clear or certain. These models are too uncertain to predict results for other altitudes and test sizes with confidence. Therefore, there is a strong need for better measuring tools and more tests that cover different altitudes and test sizes.
The Starfish test was planned to be the second in the Fishbowl series. However, the first launch, called Bluegill, was lost because the radar tracking equipment failed. The missile had to be destroyed while it was still in the air.
The first Starfish launch attempt on June 20 was also stopped mid-flight. This time, the problem was the failure of the Thor launch vehicle. The Thor missile followed a normal path for 59 seconds, but then the rocket engine stopped, and the missile started to break apart. The range safety officer ordered the missile and warhead to be destroyed. The missile was between 30,000 and 35,000 feet (9,100 and 10,700 meters) high when it was destroyed. Pieces of the missile and some radioactive material fell onto Johnston Atoll, nearby Sand Island, and the surrounding ocean.
Explosion
On July 9, 1962, at 09:00:09 Coordinated Universal Time (11:00:09 pm on July 8, 1962, Honolulu time), the Starfish Prime test was detonated at an altitude of 250 miles (400 km). The coordinates of the detonation were 16°28′N 169°38′W / 16.467°N 169.633°W / 16.467; -169.633. The actual weapon yield came very close to the design yield, which various sources have set at different values in the range of 1.4 to 1.45 Mt (5.9 to 6.1 PJ). The nuclear warhead detonated 13 minutes 41 seconds after liftoff of the Thor missile from Johnston Atoll.
Starfish Prime caused an electromagnetic pulse (EMP) that was far larger than expected, so much larger that it drove much of the instrumentation off scale, causing great difficulty in getting accurate measurements. The Starfish Prime electromagnetic pulse also made those effects known to the public by causing electrical damage in Hawaii, about 900 miles (1,450 km) away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms, and damaging a telephone company microwave link. The EMP damage to the microwave link shut down telephone calls from Kauai to the other Hawaiian Islands.
A total of 27 small rockets were launched from Johnston Atoll to obtain experimental data from the Starfish Prime detonation. In addition, a large number of rocket-borne instruments were launched from Barking Sands, Kauai, in the Hawaiian Islands.
A large number of United States military ships and aircraft were operating in support of Starfish Prime in the Johnston Atoll area and across the nearby North Pacific region.
A few military ships and aircraft were also positioned in the region of the South Pacific Ocean near the Samoan Islands. This location was at the southern end of the magnetic field line of the Earth's magnetic field from the position of the nuclear detonation, an area known as the "southern conjugate region" for the test. An uninvited scientific expeditionary ship from the Soviet Union was stationed near Johnston Atoll for the test, and another Soviet scientific expeditionary ship was in the southern conjugate region near the Samoan Islands.
After the Starfish Prime detonation, bright auroras were observed in the detonation area, as well as in the southern conjugate region on the other side of the equator from the detonation. According to one of the first technical reports:
The visible phenomena due to the burst were widespread and quite intense; a very large area of the Pacific was illuminated by the auroral phenomena, from far south of the south magnetic conjugate area (Tongatapu) through the burst area to far north of the north conjugate area (French Frigate Shoals)… At twilight after the burst, resonant scattering of light from lithium and other debris was observed at Johnston and French Frigate Shoals for many days confirming the long time presence of debris in the atmosphere. An interesting side effect was that the Royal New Zealand Air Force was aided in anti-submarine maneuvers by the light from the bomb.
These auroral effects were partially anticipated by Nicholas Christofilos, a scientist who had earlier worked on the Operation Argus high-altitude nuclear shots.
According to U.S. atomic veteran Cecil R. Coale, some hotels in Hawaii offered "rainbow bomb" parties on their roofs for Starfish Prime, contradicting some reports that the artificial aurora was unexpected.
"A 'Quick Look' at the Technical Results of Starfish Prime" (August 1962) states:
At Kwajalein, 1,400 [nautical] miles [2,600 km; 1,600 mi] to the west, a dense overcast extended the length of the eastern horizon to a height of 5 or 8 degrees. At 0900 GMT a brilliant white flash burned through the clouds rapidly changing to an expanding green ball of irradiance extending into the clear sky above the overcast. From its surface extruded great white fingers, resembling cirro-stratus clouds, which rose to 40 degrees above the horizon in sweeping arcs turning downward toward the poles and disappearing in seconds to be replaced by spectacular concentric cirrus like rings moving out from the blast at tremendous initial velocity, finally stopping when the outermost ring was 50 degrees overhead. They did not disappear but persisted in a state of frozen stillness. All this occurred, I would judge, within 45 seconds. As the purplish light turned to magenta and began to fade at the point of burst, a bright red glow began to develop on the horizon at a direction 50 degrees north of east and simultaneously 50 degrees south of east expanding inward and upward until the whole eastern sky was a dull burning red semicircle 100 degrees north to south and halfway to the zenith obliterating some of the lesser stars. This condition, interspersed with tremendous white rainbows, persisted no less than ninety minutes.
At zero time at Johnston, a white flash occurred, but as soon as one could remove his goggles, no intense light was present. A second after shot time a mottled red disc was observed directly overhead and covered the sky down to about 45 degrees from the zenith. Generally, the red mottled region was more intense on the eastern portions. Along the magnetic north-south line through the burst, a white-yellow streak extended and grew to the north from near zenith. The width of the white streaked region grew from a few degrees at a few seconds to about 5–10 degrees in 30 seconds. Growth of the auroral region to the north was by addition of new lines developing from west to east. The white-yellow auroral streamers receded upward from the horizon to the north and grew to the south and at about 2 minutes the white-yellow bands were still about 10 degrees wide and extended mainly from near zenith to the south. By about two minutes, the red disc region had completed disappearance in the west and was rapidly fading on the eastern portion of the overhead disc. At 400 seconds essentially all major
After effects
The explosion sent about 10 electrons into the Earth's magnetic field area. Some high-energy particles followed the Earth's magnetic field and created lights in the sky, while other high-energy electrons became trapped and formed radiation belts around the Earth. These added electrons greatly increased the number of electrons in the natural inner Van Allen radiation belt. At the time, scientists were unsure about the makeup, strength, and possible harmful effects of the trapped radiation. Military experts were concerned when three satellites in low Earth orbit stopped working. These included TRAAC and Transit 4B. The high-energy electrons only remained for a few days. It was not known at the time that solar and space particles could change by 10 times, and their energy could reach 1 MeV. In the months after the event, these man-made radiation belts caused six or more satellites to fail. Radiation harmed the solar panels or electronic parts of these satellites, including the first commercial relay communication satellite, Telstar 1, and the United Kingdom's first satellite, Ariel 1. Detectors on Telstar, TRAAC, Injun, and Ariel 1 measured how the radiation spread from the tests.
In 1963, it was reported that Starfish Prime created a belt of high-energy electrons. In 1968, it was reported that some electrons from Starfish remained in the atmosphere for 5 years. A year after the test, in 1963, the United States and the Soviet Union signed the Partial Nuclear Test Ban Treaty, which stopped all nuclear tests above ground. France and China continued above-ground tests for some time.
Resulting scientific discoveries
The Starfish bomb used cadmium (Cd) as a tracer to help scientists determine how quickly polar and tropical air mix during different seasons.
The teams from Christchurch, New Zealand, used a method called atmospheric photometry to measure changes in airglow in the minutes after the bomb exploded. This confirmed expected values for the decay rate of the D state of oxygen atoms. They also found that transitions from the P state to the D state of oxygen atoms happened at a rate thousands of times higher than what is normally seen in the sky due to natural processes. This showed the extensive atmospheric plasma created by the high-altitude nuclear explosion.