Starfish Prime

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The debris fireball stretching along Earth's magnetic field [1] with air-glow aurora as seen at 3 minutes from a KC-135 surveillance aircraft

The flash created by the explosion as seen through heavy cloud cover from Honolulu 1,300 km away

Another view of Starfish Prime through thin cloud

Starfish Prime was a high-altitude nuclear test conducted by the United States of America on July 9, 1962, a joint effort of the Defense Atomic Support Agency (DASA) and the Atomic Energy Commission (AEC). Launched via a Thor rocket and carrying a W49 thermonuclear warhead (manufactured by Los Alamos Scientific Laboratory) and a Mk. 4 reentry vehicle, the explosion took place 400 kilometers (250 miles) above Johnston Island in the Pacific Ocean. It was part of Operation Dominic.

Pages 19-21 of "A 'Quick Look' at the Technical Results of Starfish Prime", August 1962 states [2]:

"At Kwajalein, 1450 miles 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 greenish light turned to purple 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 seven 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 visible phenomena had disappeared except for possibly some faint red glow along the north-south line and on the horizon to the north. No sounds were heard at Johnston Island that could be definitely attributed to the detonation."

"Strong electromagnetic signals were observed from the burst, as were significant magnetic field disturbances and earth currents."

With the test taking place in such a high altitude, it was one of the five tests conducted by the USA in outer space as defined by the FAI. It produced a yield of 1.4 megatons of TNT.

The summer of 1962 was problematic for nuclear weapons aboard Thor rockets. The Bluegill nuclear test on June 4, 1962, was aborted 10 minutes after launch when the missile tracking system failed prior to nuclear detonation; the nuclear device was lost and the Thor destroyed. The original Starfish test on June 20, 1962, failed one minute after launch, again losing the nuclear device and destroying the Thor; radioactive metal and debris rained over Johnston Island. The summer concluded with extensive plutonium contamination of Johnston Island and following the failed Bluegill Prime nuclear test on July 26, 1962, which was aborted on the launch pad after the Thor engine malfunctioned on ignition.

As for Starfish Prime, because there is almost no air at an altitude of 400 kilometers, no fireball formation occurred, although manifold other notable effects did occur. About 1500 kilometers (930 statute miles) away in Hawaii, the electromagnetic pulse (EMP) created by the explosion was felt as three hundred street lights failed, television sets and radios malfunctioned, burglar alarms went off and power lines fused. On Kauai, EMP shut down telephone calls to the other islands by burning out the equipment used in a microwave link. Also, the sky in the Pacific region was illuminated by an artificial aurora for more than seven minutes. In part, these effects were predicted 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. According to the U.S. Department of Energy's (DOE) Office of Scientific and Technical Information (OSTI), the aurora was also visible and recorded on film from the Samoan Islands, about 3200 kilometers (2000 statute miles) from Johnston Island.

While some of the energetic beta particles had followed of the earth's magnetic field and illuminated the sky, other high-energy electrons became trapped in man-made radiation belts around the earth. There was much uncertainty and debate about the composition, magnitude and potential adverse effects from this trapped radiation after the detonation. The weaponeers became quite worried when three satellites in low earth orbit were disabled. These man-made radiation belts eventually crippled one-third of all satellites in low orbit. Seven satellites were destroyed as radiation knocked out their solar arrays or electronics, including the first commercial communication satellite ever, Telstar.[3]

The U.S. military realized it had no ability to collect accurate data on the intense and persistent radiation belts. This would lead Edward Teller to appropriate a satellite instrument designed and built by a young graduate student named James H. Trainor in the Physics Department at the University of New Hampshire. Trainor had no choice but to provide his instrument (originally designed to study cosmic ray neutron albedo) to the U.S. government along with all its data bus specifications and complete documentation. Trainor was not informed as to why his graduate work was being appropriated. The instrument was immediately flown to California where engineers were to graft it onto other equipment before launching it into orbit. However, the engineers apparently became confused over some technical detail and felt they needed to make better contact with the graduate student. After the data from the satellite returned to earth, and about a week after the detonation, Trainor was invited to a scientific meeting where the data collected from his instrument was discussed in a packed room at the Lawrence Livermore Laboratory.

In 1963, Brown et al. reported in the Journal of Geophysical Research that Starfish Prime had created a belt of MeV electrons, and Bill Hess reported in 1968 that some Starfish electrons remained for five years. Others reported that radioactive particles from Starfish Prime descended to earth seasonally and accumulated in terrestrial organisms such as fungi and lichens. The Starfish bomb contained Cd-109 tracer which helped work out the seasonal mixing rate of polar and tropical air masses. The early data are reviewed at [4]. The Starfish EMP waveform measured by Richard L. Wakefield of Los Alamos led to a revolution in understanding this nuclear effect and is now available at [5]. Wakefield's 1962 report is Measurement of time interval from electromagnetic signal received in C-130 aircraft, 753 nautical miles from burst, at 11 degrees 16 minutes North, 115 degrees 7 minutes West, 24,750 feet.