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Starfish Prime
Photograph taken from Honolulu of the aurora created by Starfish Prime. (credit: US government archive)

Remembering Starfish Prime

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Starfish Prime was a high-altitude nuclear test conducted by the United States on July 9, 1962. It was reported that the blast had disabled some satellites (around two dozen satellites were operational at the time), including a British bird called Ariel 1, the first ever satellite launched by the United Kingdom. The nuclear test by the US in outer space had created radioactive particles in space, which impacted the functioning of this satellite. The solar panels of Ariel 1 sustained some damage and the timer system of the satellite got disabled. Luckily, there was no major impact on the functioning of the satellite.

Reportedly, there was a loss of nine (seven were the US) of the 25 satellites in orbit at the time. The world’s first telecommunications satellite, developed by AT&T called Telstar, was launched just a day after the test. Radiations impacted Telstar’s hardware, its transistors, as well.

Reportedly, there was a loss of nine (seven were the US) of the 25 satellites in orbit at the time.

This nuclear burst in space also impacted the performance of radio systems and the electrical grid on the Hawaiian Islands for some time. The blast generated a power surge over the Pacific Ocean that led to destroying about 300 streetlights on the island of Oahu.

During this test, the US had tested a thermonuclear warhead called W49. It was a Mark 2 reentry vehicle that carried this nuclear warhead atop the US Air Force Thor intermediate-range ballistic missile. The warhead had a yield of 1.4 megatons. During this test, there was a large amount of energy released at high altitudes, which led to widespread auroras throughout the Pacific. This was the largest nuclear test ever conducted in outer space and the bomb tested was about 100 times more powerful than the one dropped on Hiroshima.

There is no clarity about the exact number of nuclear tests conducted in space. By some accounts, between 1958 and 1962 both the US and the Soviet Union conducted eight nuclear tests in space, with Starfish Prime the largest as well as first successful such test conducted by the US. Some sources claim that the US itself had conducted 11 to 12 nuclear tests in space. The Soviet Union is known to have conducted such tests under a plan called Project K. The main purpose behind such testing was to study the effects of nuclear explosions in the near-vacuum and microgravity conditions of space.

For all these years, nuclear weapon testing has been conducted in all environments: above ground, underground, and underwater. Since July 1945, more than 2,000 nuclear tests have been carried out. By 1963, atmospheric testing of nuclear weapons was banned under the Partial Test Ban Treaty (PTBT)/Limited Test Ban Treaty (LTBT). The treaty came into being because of the dangers of radioactive fallout resulting from atmospheric tests. It was signed in Moscow by the three nuclear states: the US, the Soviet Union, and the UK.

Largely, owing to the concerns about the nuclear tests conducted in space, the 1967 Outer Space Treaty (OST) was framed. It covers various aspects related to space and essentially bans the stationing of weapons of mass destruction (WMD) in outer space. The treaty stresses that the medium of space should be used only for peaceful purposes and no military activities should be carried out on celestial bodies.

Against that backdrop and as we approach the 62nd anniversary of Starfish Prime, it is important to put in context the recent claims made by the US that Russia could be planning to put nuclear weapons in space. Obviously, Russia has denied this allegation. Normally, US intelligence assessments are mostly accurate, however in this case there have been few specific details about presence of Russian nukes in space. But the current US messaging itself is sufficient to at least start a debate on such possibilities in the future.

Today, the US has major concerns about counterspace capabilities developed by Russia as well as by China. In 2021, Russia performed an anti-satellite test (ASAT) that has led to the generation of more than 1,500 pieces of trackable orbital debris. According to some assessments, the launch of Cosmos 2576 on May 16 by Russia could be associated with their space weapons program. There are various possibilities that are being debated in this regard. This launch is similar to earlier launches in 2019 and 2022. These satellites had ejected some objects into space and were closely following US National Reconnaissance Office (NRO) satellites. It appears that possibly the purpose behind this was to send a message as well as to test technology.

Cosmos 2576 could be an inspector satellite in low Earth orbit (LEO) with a purpose to keep a track of the US spy satellite since it has been trailing one such satellite. There is also a possibility that this satellite could be a space weapon designed to destroy or disable satellites in orbit. Russia has given the official purpose behind launching this satellite as a system meant to study the effects of radiation on electronics. However, it has not been placed in space in the region where it would encounter an apt radiation environment for such testing. Interestingly, on June 26 a decommissioned Russian satellite suffered a breakup event, creating more than 100 pieces of debris. The reasons behind sudden fragmentation of this satellite are not known or have not been made public by Russia.

Any intentional nuclear blast in LEO would be a disaster for the entire world.

Any nuclear explosions in space would have different types of effects depending on the orbit and environment around in which these satellites are placed. Any such blast in high altitudes could generate an electromagnetic pulse (EMP), which would damage electronics on the satellite. This could also lead to change in ionospheric properties that would adversely impact telecommunications.

Starfish Prime demonstrated that radiation impacts spacecraft electronics. After a blast in space, there could be appearance of some thermal stress, owing to the presence of high-energy particles. This could impact functioning of solar cells and could similarly affect the communications systems. It is important to note that the radiation dose could impact satellites for years. The Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind. However, a nuclear blast in space could create an artificial Van Allen belt that could impact the health of satellites passing through these regions.

Currently, there are around 9,900 operational satellites in space in all orbits. Russia could have around 200 operational satellites, but as of June 2024, there are more than 6,200 Starlink satellites in orbit, of which more than 6,100 are working, according to astronomer Jonathan McDowell. There are some other megaconstellations operating in space too. In addition, there are two space stations, which are housing astronauts; the ISS has Russian cosmonauts there. Any intentional nuclear blast in LEO would be a disaster for the entire world.

On April 24, a resolution was presented in the UN Security Council that reaffirmed the OST’s prohibition on nuclear weapons in space and a commitment towards not developing such weapons ever. Since Russian President Putin has already denied any possibility of Russia putting nuclear weapons in space, this was an opportunity for him to “walk the talk.” However, this resolution could not be adopted since Russia vetoed it. Today, it cannot be said with certainty that Russia has an interest in space nukes, but such a possibility cannot be denied. Hopefully, Russia takes some lessons from Starfish Prime.

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