The world's largest nuclear explosion in space took place 64 years ago. On July 9, 1962, the United States carried out the Starfish Prime test by detonating a 1.4-megaton thermonuclear bomb about 400 kilometres above Earth. It was roughly the same altitude at which the International Space Station now orbits.
The explosion created a bright flash that was visible from hundreds of kilometres away and produced artificial radiation belts around Earth. These man-made radiation belts damaged several satellites in orbit and remained for more than five years.
Just a year later, in 1963, the United States, the Soviet Union and the United Kingdom signed the Partial Nuclear Test Ban Treaty, which banned nuclear tests in the atmosphere, outer space and underwater. This further led to the development of the 1967 Outer Space Treaty.
The Outer Space Treaty is the main international agreement that sets the basic rules for how countries can use space. It was opened for signing in January 1967 and it came into force in October 1967. As of 2024, 115 countries are part of this treaty and another 22 countries are signatories.
What was Starfish Prime?
Starfish Prime was a US nuclear weapons test carried out on July 9, 1962, during the Cold War. The explosion was part of Operation Fishbowl, a series of high-altitude nuclear tests under the larger Operation Dominic.
The explosion produced a powerful electromagnetic pulse (EMP), a burst of energy that affected electrical and electronic systems. Even though the blast took place about 1,450 kilometres away, it knocked out around 300 streetlights in Hawaii.
All about the 1967 Outer Space Treaty
The treaty says that outer space belongs to all countries and that no nation can claim ownership of the Moon, planets or any other celestial body. It also bans countries from placing nuclear weapons or other weapons of mass destruction in orbit or anywhere else in space.
Under the treaty, the Moon and other celestial bodies must be used only for peaceful purposes and astronauts should be treated as representatives of all humanity and given help. It also makes countries responsible for their space missions and liable for any damage caused by their spacecraft or satellites.
