The story of Cosmos 954, the nuclear satellite that fell from space to Earth
No bird flew and rose except as it flew and fell.. This wisdom applies to satellites as well, which are currently circling around the Earth's orbit.
The space agencies responsible for the satellites will return them to Earth after their missions are over, where they will burn up in its atmosphere at high altitudes.
In fact, sometimes only a few parts of it reach the ground, and at other times, some satellites fall unexpectedly back to Earth, which poses a danger to humans, wildlife, and the environment, and it gets worse if this satellite is powered nuclear.
During the Cold War era, both the USA and the Soviet Union launched dozens of nuclear-powered satellites into space. The first of these satellites was Transit-4A, which was launched by the USA in 1961.
It was one of several satellites launched between 1959 and 1988 to provide navigation services to the US Navy, and it was also the first to provide satellite navigation services before GPS.
In total, the Transit system had 41 satellites in Earth orbit, some of which were nuclear powered, and many of these satellites, although out of service, are still orbiting the Earth today, and their nuclear reactors are still intact.
Between 1964 and 1978, the United States launched 7 more nuclear-powered satellites under the Nimbus program. Nimbus satellites have helped meteorologists study Earth's weather, climate change, ozone layer, sea ice and so on.
Of the seven Nimbus moons, two are still in Earth's orbit.
The Soviet Union began launching nuclear-powered satellites into space in 1965, and over the ensuing 22 years they launched more than thirty satellites of this type, each carrying a small nuclear reactor in order to supply it with the energy needed to carry out the tasks assigned to it. with it.
Most of these satellites were of a reconnaissance nature, and were intended to spy on the US Navy and its submarines. These satellites used radars to monitor the US Navy's maritime traffic, and because the radars lost signal quickly with distance, the Soviets would orbit their spy satellites at a relatively low altitude.
Air resistance prevented the use of large solar panels to power the satellite, making nuclear power the ideal alternative at the time for such missions.
Most of these satellites carried BES-5 nuclear reactors that run on uranium-235. Because of their limited space and weight, the uranium they powered had to be highly enriched to weapon-grade, so these reactors were fast, highly efficient, and small at the same time, not to mention very powerful.
The BES-5 nuclear reactor weighed less than 400 kg and was producing 100 kilowatts of thermal energy, of which 3 kilowatts was converted into usable electrical energy.
The nuclear reactor was installed in a separate unit so that it could be flung away into space into a higher orbit once the satellite reached its expiration date. In this way, the expired satellite could safely return to Earth without polluting the atmosphere with nuclear radiation.
But here it is about spaceflight missions, and it is natural that things do not always go according to plan.
Cosmos 954 . satellite
The Cosmos 954 satellite was launched on September 18, 1977 from the Baikonur Cosmodrome in Kazakhstan, and shortly before it entered Earth's orbit. On board this satellite, there was a thermoconverter operated by a nuclear reactor containing about 50 kilograms of highly enriched uranium-235.
Within weeks of its launch, this satellite's orbit had become so volatile and unstable that the Soviets were well aware that its service life would be very short. As mission supervisors struggled to control this turbulent satellite, they eventually realized that Cosmos 954 would soon fall back to Earth.
To make matters worse, the system that was supposed to throw the nuclear reactor away into space in the event of a satellite failure was also not working due to a malfunction.
In a rare and rarely characteristic sense of responsibility for the Soviet Union, Soviet officials notified the United States, as well as the countries that were directly under the damaged satellite's orbit, and informed them of the possibility of it falling into their territories, which might result in nuclear radiation.
In a series of secret meetings with US officials, USSR officials provided some detailed information about the nuclear reactor operating the Cosmos 954 satellite. Helping her clean up any radioactive nuclear contamination that might result.
Scheme of the BES-5 nuclear reactor aboard the Soviet Cosmos 954 satellite.
On January 24, 1978, minutes before sunrise, Cosmos 954 entered Earth's atmosphere and crashed over Canada. Fragments from this satellite occurred along a 600-kilometre stretch from Great Slave Lake to Pike Lake.
The search and cleanup operations cost the Canadian treasury 14 million Canadian dollars, while the United States spent about 2.5 million US dollars for the same purpose. Canada later billed the Soviet Union to compensate for C$6 million in losses, of which the Soviet Union only paid half.
The satellite is believed to have weighed between 4 or 5 tons, and only 65 kilograms of debris, which was all radioactive, has been recovered.
Fears soon spread that a large enough section of the Cosmos 954 nuclear reactor might have survived the crash and made its way through sea ice to the sea floor, where it could become extremely dangerous. The reason for this is that water acts as a moderator, slowing down the movement of neutrons, allowing the chain reaction to start over.
Experts did some calculations and found that only 22 kg of HEU could be a significant hazard in such circumstances.
Despite lengthy and diligent searches, the nuclear reactor was never found. Researchers and experts have come to the conclusion that the nuclear reactor has almost completely disintegrated and has become dormant.
In a research study published in August 1984 in the journal Health Physics, researchers concluded that at least a quarter of the nuclear reactor (i.e. between 7 to 8 kilograms) had fallen in the form of particles no more than 1 mm in diameter, which fell to the ground in the form of Invisible slow fog over northwestern Canada and over the arctic and subarctic barren lands. The remaining three quarters evaporated into a fine mist and remained suspended in the atmosphere for years, before slowly descending to the Earth's surface.
By this time, radioactive decay would have been sufficiently advanced to remove most of the radionuclides presenting less of a health risk.
As for radioactive particles with a diameter of 1 mm, the researchers indicated that if a person accidentally swallowed them, they would cross his digestive path and exit his body without any significant damage after 48 hours, and their effects on his health were as if he had conducted an X-ray scan. .
Search for radioactive debris.Photo: Nevada National Security
Interestingly, Cosmos 954 was not the first nuclear-powered satellite to fall from space. In 1973, a failed launch of another such satellite caused the nuclear reactor to fall in the Pacific Ocean north of Japan.
Another Soviet spy satellite, Cosmos 1402, malfunctioned and fell into the Indian Ocean in 1983.
The ejection system again failed to catapult the nuclear reactor into a higher orbit causing it to fall separately from the satellite carrying it a few days later over the Atlantic Ocean.
Worst of all, there is a high probability that something like this will happen in the future, as many of the nuclear-powered satellites that were launched into Earth orbit in the Cold War era are still orbiting the Earth. Although their orbits are relatively higher and are somewhat stable, hitting any space debris and junk may cause them to deviate from their paths and fall to Earth.
Nuclear energy is still used in space exploration, as it is still used on vehicles and exploratory and reconnaissance mechanisms in the form of Mars Rover that are present on Mars now to gather information about it, but it is no longer used to operate satellites that revolve in Earth’s orbit, because the danger that may result from it exceeds The benefits that may accrue from it.
A piece of a satellite in the snow.Photo: Library and Archives Canada
Fragments and debris of the Cosmos 954 satellite at the Museum of Science and Technology of Canada.Photo: Canada Science and Technology Museum
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