Scientists calculate whether someone will die from space debris falling from the sky

The likelihood that someone will die from space debris falling from the sky may seem very small. As a result, no one has died so far, although there have been cases of injuries and damage to property.

But with more and more satellites, rockets and probes being launched into space, it’s worth considering whether we should start taking risks more seriously.

So a new study, published in the journal Nature Astronomy, sought to estimate the likelihood of casualties from falling rocket parts over the next 10 years.

And every minute of every day, it’s raining down on us from outer space, a danger we’re barely aware of. Microscopic particles from asteroids and comets travel through the atmosphere and settle unnoticed on the Earth’s surface, producing about 40,000 metric tons of dust every year.

While not a problem for us, such debris can damage a spacecraft, as was recently reported on the James Webb Space Telescope.

From time to time a larger sample arrives in the form of a meteorite, and perhaps once every 100 years an object within tens of meters manages to bypass the atmosphere to dig a hole in the ground.

Fortunately, kilometer-sized objects rarely reach the surface, causing death and destruction, as evidenced by the extinction of the dinosaurs. These are examples of natural space debris, the uncontrolled arrival of which is unpredictable and more or less uniformly distributed throughout the world.

However, the new study looked at uncontrolled access to artificial space debris, such as spent rocket stages, associated with rocket and satellite launches.

Using mathematical modeling of the inclinations and orbits of the rocket parts in space and the population density below, as well as satellite data from the past 30 years, the researchers estimated where the rocket debris and other unwanted parts of the Earth would end up in space when they hit Earth. .

They find that there is a small but significant risk of detail reappearing in the next decade. But it happens more often in southern latitudes than in northern latitudes.

In fact, the study found that missiles were about three times more likely to land at the latitudes of Jakarta in Indonesia, Dhaka in Bangladesh or Lagos in Nigeria than in New York in the US, Beijing in China or Moscow. in Russia.

The scientists also calculated the “expected loss” – the danger to human life – over the next decade as a result of the return of unguided rockets.

Assuming that each return scatters deadly debris over an area of ​​10 square meters, they found that there is, on average, a 10 percent chance of one or more victims over the next decade.

Until now, the possibility that debris from satellites and rockets could cause damage to the Earth’s surface (or air traffic) has been ignored.

Most of the research on this space debris has focused on the risks associated with non-operational satellites in orbit, which can prevent the safe operation of active satellites. Unused fuel and batteries also lead to orbital explosions, which produce additional waste.

But as the number of participants in the rocket launch business increases – and the transition from state to private enterprise – it is very likely that the number of accidents, whether in space or on Earth, will also increase.

But a new study says a 10 percent chance is still a conservative estimate.

What can he do?

There are a number of methods that allow you to completely control the re-entry of debris into the atmosphere, but their implementation is prohibitively expensive. For example, a spacecraft may be “passivated” (put to rest) where unused energy (such as fuel or batteries) is spent rather than stored after the spacecraft has become obsolete.

The choice of satellite orbit can also reduce the chance of debris being generated. A failed satellite can be programmed to go into low Earth orbit, where it will burn up.

There are also attempts to launch reusable rockets like those being developed by SpaceX and Blue Origin.

Several agencies are taking the risk very seriously, with the European Space Agency planning a mission to capture and remove space debris using a four-armed robot.

In 2010, the United Nations, through its Office for Outer Space Affairs, issued a set of space debris mitigation guidelines that were strengthened in 2018. However, as the authors of the new study note, these are more guidelines than international law. does not provide details on how mitigation measures will be implemented or monitored.

The study argues that advances in technology and better mission design will reduce the rate of uncontrolled re-entry of spacecraft debris, reducing risks worldwide.

It is noteworthy that in five years it will be 70 years since the launch of the first satellite into space.

Source: phys.org.