Researchers at the Northwest Institute of Nuclear Technology in Xi’an, which operates under the auspices of the People’s Liberation Army (PLA), said they have developed a model to estimate the severity and extent of damage caused by a nuclear anti-satellite weapon at various locations above sea level.
The researchers found that a 10-megaton warhead detonated at an altitude of 80 kilometers would pose a serious threat to satellites.
The study found that such a nuclear explosion turns air molecules into radioactive particles, producing a more inverted pear-shaped cloud, CPLA nuclear physicist Liu Li and his colleagues said in a research paper published Oct. 15 in the journal Nuclear Techniques.
It is said that in five minutes this cloud will spread to a height of about 500 kilometers and will spread over an area of more than 140,000 square kilometers. “The strong residual radiation in these clouds … could cause failures or destruction of spacecraft carrying satellites and even cause direct damage,” the researchers said.
Liu’s team said it conducted computer simulations before studying the use of nuclear anti-satellite weapons in space. However, it turns out that a nuclear explosion in space does not produce much of a cloud due to the lack of air. According to Liu’s team.. ‘The high-energy particles produced by this event are mostly captured by the geomagnetic field… forming a global radiation belt… posing a threat to a wide range of spacecraft… nuclear weapons are dangerous to satellites’.
However, clouds are formed due to the presence of air molecules caused by an explosion in a nearby space. According to Liu.. ‘The mass of the cloud formed is much greater than that of the bomb. Liu’s team said, ‘The gamma and beta rays emitted by the high density of the debris cloud from disintegration within it are strong… and have a strong impact on spacecraft and communications in the affected area.’
Immediately after the explosion, the cloud rises at a speed of 2.3 kilometers per second, creating a trap for the targeted satellites, the researchers explained. Also, air molecules, instead of remaining in orbit, return to Earth unlike a space-based explosion. Thus the radiation belt effect can be avoided. This significantly reduces the risk to other satellites or spacecraft.
The PLA is a nuclear anti-satellite deterrent weapon that allows Starlink satellites placed in low Earth orbit (LEO) to be disabled or destroyed. Concerns about the risks associated with the Starlink satellite internet system were raised in May this year by the official journal of the Chinese Armed Forces. It indicated that the US military could dominate outer space where it was used.
There were 60 Starlink satellites as of 24 May 2019 before the expansion. “SpaceX has decided to increase the number of Starlink satellites from 12,000 to 42,000. The program’s unchecked expansion and the company’s ambitions to use it for military purposes have alarmed the international community,” a Chinese military website article said. The article was published by the website of the Central Military Commission (CMC), China’s top national defense body headed by President Xi Jinping.