PLANETARY SECURITYScientists Calculate the Risk of Someone Being Killed by Space Junk
The chance of someone being killed by space junk falling from the sky may seem ridiculously tiny. 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?
The chance of someone being killed by space junk falling from the sky may seem ridiculously tiny. After all, nobody has yet died from such an accident, though there have been instances of injury 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 Astronomy, has estimated the chance of causalities from falling rocket parts over the next ten years.
Every minute of every day, debris rains down on us from space – a hazard we are almost completely unaware of. The microscopic particles from asteroids and comets patter down through the atmosphere to settle unnoticed on the Earth’s surface – adding up to around 40,000 tons of dust each year.
While this is not a problem for us, such debris can do damage to spacecraft - as was recently reported for the James Webb space telescope. Occasionally, a larger sample arrives as a meteorite, and maybe once every 100 years or so, a body tens of meters across manages to drive through the atmosphere to excavate a crater.
And – fortunately very rarely – kilometer-sized objects can make it to the surface, causing death and destruction – as shown by the lack of dinosaurs roaming the Earth today. These are examples of natural space debris, the uncontrolled arrival of which is unpredictable and spread more or less evenly across the globe.
The new study, however, investigated the uncontrolled arrival of artificial space debris, such as spent rocket stages, associated with rocket launches and satellites. Using mathematical modelling of the inclinations and orbits of rocket parts in space and population density below them, as well as 30 years’ worth of past satellite data, the authors estimated where rocket debris and other pieces of space junk land when they fall back to Earth.
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 over southern latitudes than northern ones. In fact, the study estimated that rocket bodies are approximately three times more likely to land at the latitudes of Jakarta in Indonesia, Dhaka in Bangladesh or Lagos in Nigeria than those of New York in the US, Beijing in China or Moscow in Russia.
