A new study reveals that in the next decade, there is a 10% chance that someone will die due to being hit by falling space debris.
It sounds like a scene straight out of a cartoon: a piece of metal breaks off from a rocket or satellite, re-enters the atmosphere, and then plummets to the ground. It has the potential to destroy everything in its path—be it a puddle on the road, a flower bed, or a city bus.
This scenario may seem far-fetched, but in reality, the unpredictable consequences of space debris are increasingly becoming a tangible threat to humanity.
At the end of July 2022, a leftover piece of China’s Long March 5B rocket re-entered the atmosphere before crashing into the Sulu Sea near the Philippines.
This is not a rare occurrence. The continuous increase in satellites globally means there are now more artificial objects in space than ever before. A new study predicts that the likelihood of someone dying from being struck by falling space debris in the next decade is not low.
Space debris will soon become a problem for Earth’s inhabitants – (Photo: Internet).
Overflowing with Space Debris
A massive amount of space debris is “surrounding” the Earth’s atmosphere. It is estimated that there are hundreds of thousands of tiny objects, each about 1 cm or larger, re-entering the atmosphere and falling to Earth.
“These fragments create a continuous “rain” of objects returning to Earth that we cannot track. They come down all over the Earth,” said Marlon Sorge, executive director of the Orbital Debris Reentry Research Center at the Aerospace Corporation, in an interview with Astronomy.
However, “because these fragments are very small,” he added, “even when they fall to the Earth’s surface, they do not pose a danger to people on the ground and will go unnoticed.”
Nonetheless, larger debris regularly re-enters the atmosphere. Statistics show that about one ton of space debris enters the atmosphere every week. But Sorge emphasizes that this rate is an average. This means that there will be periods of “quiet”—when the number of larger debris entering the atmosphere is not significant. Conversely, there will be times when a multitude of large fragments will fall to Earth in a short period.
Of course, an object entering the atmosphere does not mean it will crash into the Earth’s surface. According to the Aerospace debris database, up to 60% of space debris burns up completely during re-entry. Most of the objects that make it through the atmosphere end up falling into the ocean, far from populated areas.
However, there are currently more fragments of space debris in the atmosphere than ever before. For example, in 2021, over 1,900 space objects were recorded and classified in the United Nations database. Most of these space objects are satellites, which are increasingly used for communication and weather monitoring. Fortunately, satellites are now smaller than before, and Sorge notes that they are being designed to create less space debris. But the increasing number of large satellites in orbit also means that the issue of space debris needs to be addressed.
What is the likelihood of someone dying from being hit by space debris?
What are the chances that someone could be killed by falling space debris? In a 2022 study published in Nature Astronomy, a team of researchers at the University of British Columbia sought to find the answer.
There is a 10% chance of fatalities due to falling space debris. (Photo: Internet).
They turned to an open database that records information about objects still in orbit, as well as those that have burned up and disappeared upon re-entry. They discovered that over the past three decades, more than 1,500 rocket body parts have re-entered our atmosphere. Over 70% of these have uncontrolled re-entry orbits. The research team then calculated the probability of one of these rocket bodies re-entering the atmosphere (like the recent Long March 5B part) and actually hitting someone on the ground. They concluded that in the next decade, there is a 10% chance of fatalities due to falling space debris.
“Our estimates are conservative. It’s probably worse than that,” said Aaron Boley, a professor at the University of British Columbia and one of the study’s authors.
Scientists do not always know for certain how a piece of space debris will re-enter the atmosphere or its trajectory, as they move in chaotic and unpredictable ways.
Moreover, there are many factors that can be considered variables affecting the flight path of space debris, such as the air resistance they encounter.
Boley stated: “The problem is you don’t know where it will come down until you track it for one or two orbits before it re-enters the atmosphere. You can make your absolute best measurements, but the reality is that this object is tumbling through space.
However, scientists say that it is possible to better manage or completely avoid these uncontrolled re-entries.
For example, some components are designed to detach from the rocket, and researchers have found that their orbits can be directed almost precisely to less populated areas of the world.
Space debris can return to Earth in various shapes and sizes – (Photo: Internet).
A 2021 study published in Advances in Space Research examined re-entry models to determine how to minimize the risk of fatalities by analyzing the trajectory of an object after its first re-entry.
Inna Sharf, a professor at McGill University in Montreal and one of the study’s authors, stated: “The location where debris falls depends greatly on its trajectory at the start of the experiment. Important orbital factors include how circular the orbit is and where it intersects with the Earth’s equatorial plane.”
“According to our theory, by giving the debris a small but timely impulse, for example, by attaching and firing a thruster to the debris for a very short period, we can easily influence where the debris lands on Earth,” Sharf explained.
Currently, space debris does not fall everywhere on our planet’s surface. They tend to fall more in the Southern Hemisphere—while countries in the Northern Hemisphere are primarily responsible for the debris.
“Not only do many countries intentionally “forget” their leftover parts in orbit, but they also do not adhere to their own rules during rocket launches into space. For example, most of the U.S. rocket launches in recent decades have neglected the requirements for controlled re-entry.”
Due to the relatively low risk of causing damage, this has led space organizations to be lax in implementing appropriate precautions.
But with space organizations worldwide having loosened regulatory oversight, the upcoming consequences will be unpredictable. The impacts of rocket launches or satellite deployments into space will gradually accumulate over time, enough to cause serious repercussions.
“Space agencies could do more to reduce the amount of space debris re-entering the atmosphere. Rockets can now be designed with reusable engines that allow for controlled re-entry.”
