Space traffic has a 1 in 4 probability of stopping the committed air traffic every year. Credit: Tapish/UNSPLASH
In November 2022, a Chinese rocket for a long March 5 billion returned to the atmosphere without any ability to control where he fell. By precaution, France, Spain and Monaco have closed part of their airspace along the possible path of the booster.
As happened, the rocket returned to the Pacific Ocean, not in Europe. But the closings of the airspace have still involved that 645 planes were delayed by an average of almost half an hour. The unexpected diversions have also led to congestion in the skies over the nations that have chosen not to close their airspace.
Although the impacts were relatively minor, the risk of occurrences as if it continues to grow with the increase in traffic of space and air traffic. And while the chances of an out of control rocket that collide with a plane are low, the result could be catastrophic.
In a study published in Scientific relationships On January 23, Ewan Wright, a doctoral student at the University of British Columbia in Vancouver, Canada, and his colleagues calculated the probability of spatial debris from rockets that fell into the crowded airspace, which could cause delays or even accidents and victims.
Is the sky falling?
Wright and his colleagues focused on the return of missile bodies. Despite the growing tendency of the reusable boosters introduced by Spacex, most of the rockets still use sacrificable phases that return to Earth immediately after they have reimbursed their useful loads. And many upper rocket phases are abandoned in orbit and could return later. (Starting from March 2025, over 2,000 missile bodies are still in Earth orbit, according to the space of space debris of the European Space Agency.)
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While some spatial objects burn completely in the atmosphere, due to their large size, the missile bodies are much more likely to break in debris that survive to return and fall on earth.
Even the smallest of the objects can create problems for a plane. An object that falls from the space approximately the weight of a paper clip (about 0.04 ounces or a gram) could cause damage to a plane if it affects the windshield or is sucked into an engine. A piece of debris greater than 0.3 ounces (9 g) could affect a hole in the body of a plane and an object lower than a pound could cause a catastrophic crash.
To calculate the chances of such a disaster, the authors analyzed where the rockets are more likely to fall on the basis of the historical data of their orbits in the last ten years. So they evaluated that information against the way the crowded terrestrial skies are based on the 2023 tracking data from Transponder.
The chances of a collision are still low. Considering the actual exposed area of a plane (which is larger than the plan itself due to its speed), the study estimates that the probability of debris collide with one plan is about 1 out of 430,000 every year. However, the authors say that it is a conservative esteem, as it does not take into account the fact that the rocket bodies break in many other pieces as they fall within.
Chain impacts
As the return of the long March 5B shows, also debris forecasts can lead to closures and delays in the airspace, offering economic costs to airlines and passengers. According to international law, the nation that launched the rocket could be responsible for these costs.
To understand how air traffic operations could be interrupted, the team has studied the chances of a rocket that falls into the crowded airspace. They discovered that the probability of an uncontrolled return near one of the main most crowded international hubs such as Atlanta, New York or London is about 0.08 percent per year. But when they consider busy areas around other important airports and in the crowded airways all over the world – as parts of the North -Eastern United States, of Northern Europe and around the main cities of Asia – the annual probability of missile debris that falls in a heavily busy region is 26 percent.
It does not help the fact that uncontrolled debris are difficult to predict in advance. The Federal Aviation Commission of the United States observed in a 2023 report which, even within 60 minutes of the return, the potential area in which the debris could fall extends still at 1,240 miles (2,000 km).
National and international organizations played the alarm for the return of uncontrolled rockets and the policies proposed to reduce the risks for safety. But, the authors note, there is very little application to prevent these accidents from occurring.
