For many years, the impact of global warming on the earth’s environment is well known to the world, but the latest research results show that global warming also deeply affects space safety – nature will clear the space debris flying around the earth’s orbit at high speed more and more slowly, threatening the safety of satellites and other spacecraft operating in these orbits.
The Thin Atmosphere of Low-Earth Orbit Can Clean Up Space Debris
This scientific research report jointly released by researchers from the Massachusetts Institute of Technology and the University of Birmingham in the United Kingdom and published in the British journal Nature-Sustainability shows that global warming and the increase of greenhouse gases such as carbon dioxide in the atmosphere will cause more heat to be released into outer space in the form of infrared radiation, resulting in cooling and contraction of air high in the atmosphere, which directly affects the reduction of the density of the thin atmosphere in low-Earth orbit.
According to reports, low-Earth orbit is usually about 200-2000 kilometers from the ground. At present, most satellites operate at an altitude of about 200-600 kilometers. Rocket debris, abandoned satellites, space debris, etc. generated by various human space activities also mainly linger here. There is still an extremely thin atmosphere in low-Earth orbit, and spacecraft operating in it will be dragged and gradually slow down, and eventually fall into the atmosphere. The good news is that the thin atmosphere in low-Earth orbit is also nature’s way of cleaning up space debris. Under normal circumstances, space debris will be slowed down by air resistance and burn up when it enters the atmosphere. “We rely on the atmosphere to clean up the space debris we create, and there is no other way to replace it,” said Will Parker, the first author of the report and a researcher in astrodynamics at MIT.
The Phenomenon of Reduced Atmospheric Density May Intensify
As global warming causes the air density in low-Earth orbit to decrease and atmospheric drag to decrease, space debris will stay in orbit longer, threatening the normal operation space of satellites. Simulations show that as global warming caused by the burning of coal, oil and natural gas continues, the available space for satellites in low-Earth orbit may decrease by 33% to 82% by the end of this century. This prediction has also been confirmed by other scientists. Ingrid Knossen, a space weather scientist at the British Antarctic Survey, said that the density of the atmosphere about 250 miles (about 400 kilometers) above the surface decreases by about 2% every 10 years on average, and as human society emits more greenhouse gases into the atmosphere, the phenomenon of atmospheric density reduction may intensify.
Relevant statistics show that there are hundreds of millions of space debris orbiting the earth, including millions of fragments with a diameter of 3 mm or larger, and the energy of their collision is equivalent to that of a bullet; there are tens of thousands of pieces of space junk the size of plums, and the power of their collision is equivalent to that of a bus collision. Since the first satellite launch by humans, about 20,000 satellites have been sent into space, and about 12,000 are currently in operation.
The Risk of Satellite Collision is Rising Rapidly
In the past 10 years, with the large-scale launch of the “Starlink” Internet communication satellites by SpaceX, the number of satellites in low-Earth orbit has increased rapidly, and the resulting collision risk has also increased rapidly. In the first half of 2024 alone, SpaceX controlled the Starlink satellite to make more than 50,000 emergency orbit changes to avoid collisions between satellites and space debris and other spacecraft.
Parker said: “There used to be a saying that space is big, so we don’t necessarily need to be good stewards of the space environment because the overall carrying capacity is basically unlimited.” But now everything has changed. Researchers predict that even if the number of satellites in a local orbit exceeds the carrying capacity, the area will experience “uncontrolled instability”, that is, chain collisions and a large amount of space debris will occur, making it impossible for satellites in the area to operate safely.
This new study on the impact of global warming on space safety is very meaningful. Scientists must not only pay attention to the impact of global warming on human society, but also be aware of the impact of climate change on the Earth’s orbit in order to take appropriate measures to ensure the long-term sustainability of the Earth’s orbit.
