The chances of someone being killed by space junk falling from the sky may seem ridiculously small. After all, no one has died from such an accident so far, although there have been cases of injuries and damage to property.
But given that we are launching an increasing number of satellites, rockets and probes into space, do we need to start taking the risk more seriously?
a new study, published in nature astronomyThe U.S. has projected the potential for casualties from falling rocket parts over the next ten years.
Every minute of every day, debris pours down on us from space – a danger we are almost completely unaware of. Microscopic particles from asteroids and comets traipse down through the atmosphere to pass unnoticed on Earth’s surface – adding up to about 40,000 tons of dust each year.
While this isn’t a problem for us, debris like this could damage spacecraft – as was the case recently. Reported for the James Webb Space Telescope, Sometimes, a large sample a . comes as MeteoriteAnd maybe once every 100 years, manages to drive through the atmosphere to dig a crater tens of meters across.
And – fortunately very rarely – kilometer sized objects can build up on the surface, causing death and destruction – as shown by a lack of dinosaur Today the earth is rotating. These are examples of natural space debris, whose uncontrolled arrival is unpredictable and is more or less uniform across the globe.
However, the new study examined the uncontrolled arrival of artificial space debris, such as spent rocket stages attached to rocket launches and satellites.
Using mathematical modeling of the inclination and orbits of rocket parts in space and the population densities beneath them, as well as 30 years’ worth of past satellite data, the authors estimated when rocket debris and other fragments of space would return to land. Huh. ,
They found that there is a small, but significant risk of parts re-entering in the coming decade. But this is more likely to happen at southern latitudes than at northern latitudes.
In fact, the study estimated that rocket bodies are nearly three times more likely to occur at latitudes in Indonesia, such as Jakarta in Indonesia, Dhaka in Bangladesh, or Lagos in Nigeria, than New York in the US, Beijing in China, or Moscow in Russia. ,
The authors also calculated a “casualty expected” – a risk to human life – as a result of uncontrolled rocket re-entries over the next decade. Assuming that each re-entry spreads deadly debris over an area of ten square metres, they found that the probability of one or more casualties on average over the next decade is 10 percent.
To date, the potential for damage to the Earth’s surface (or to air traffic in the atmosphere) by debris from satellites and rockets has been considered negligible.
most studies of space debris In-orbit risk posed by inactive satellites that could interfere with the safe operation of working satellites. Unused fuel and batteries also cause an in-orbit explosion which generates additional waste.
But as the number of entries into the rocket launch business grows – and moves from government to private enterprise – it is highly likely that the number of accidents, both in space and on Earth, such as those occurred after launch. Chinese Long March 5bwill also increase.
The new study warns that the 10 percent figure is therefore a conservative estimate.
what can be done
There are a number of technologies that make it entirely possible to control debris re-entry, but they are costly to implement. For example, spacecraft may be “inactivated”, whereby unused energy (such as fuel or batteries) is expended rather than stored after the spacecraft’s lifetime is over.
The choice of orbit for the satellite can also reduce the potential for debris generation. A passive satellite can be programmed to be carried into low Earth orbit, where it will burn up.
Efforts are also being made to launch reusable rockets, for example. SpaceX performed and blue original is developing. These create very little debris, although some will be from paint and metal shavings, as they return to Earth in a controlled manner.
Many agencies take the risk seriously. The European Space Agency is planning a mission Try to capture and remove space debris with four-armed robot, The United Nations, through its Office of Outer Space Affairs, issued a set of Space Debris Mitigation Guidelines in 2010, which was Reinforced in 2018,
However, as the authors of the new study point out, these are guidelines, not international law, and do not specify how mitigation activities should be implemented or controlled.
The study argues that advanced technologies and more thoughtful mission design will reduce the rate of uncontrolled re-entry of spacecraft debris, reducing the risk of a worldwide threat. It states that “uncontrolled rocket body reentry constitutes a collective action problem; solutions exist, but each launching state must adopt them”.
The need for governments to act together is not unprecedented, as shown by the sanctions agreement. ozone Chlorofluorocarbon chemicals that destroy the crust.
But, unfortunately, such an action usually requires a major event with significant consequences for the Northern Hemisphere before action can be taken. And changes to international protocols and conventions take time.
In five years, it will be 70 years first satellite launch in the space. It would be a fitting celebration of that event if it could be marked by a strong and mandatory international treaty on space debris, ratified by all UN states. Ultimately, such an agreement will benefit all countries.