A group of Canadian researchers at the University of British Columbia calculated that the risk of one or more people being killed by uncontrolled rocket descents is about 10% over the next decade. Michael Byers, Ewan Wright, Aaron Boley, and Cameron Byers describe their study of casualty risk in the coming years due to rocket parts falling from the sky in their paper published in the journal Nature Astronomy, as well as what governments could do to make spaceflight safer for people on the ground.
After completing their missions, rocket parts, satellites, and even space stations have fallen back to Earth over the past several decades. To date, no one has been killed by falling space debris, though one person is believed to have been struck: Lottie Williams, who was walking in a park in 1997 when she was struck by debris. However, as the space age has progressed, more rockets and satellites have been launched into orbit, and this trend is expected to continue. The researchers calculated the likelihood of one or more people being struck or killed by such objects if current practises are followed.
The researchers examined the current number of rockets launches as well as the number expected to increase over the next decade. They also investigated what happens to rocket parts when they fall back to Earth, as well as where they usually land. The majority, as expected, fall into the ocean, which covers so much of the planet, according to the researchers. However, they discovered that as the number of rockets launched increases, so does the likelihood of one or more of them collapsing in a populated area—they estimate that the chance of one or more fatalities in the coming decade is around 10%.
They also discovered that people living in certain areas face greater risks. This is because of the flight paths of the rockets that are launched. They discovered that the risks were greatest in Indonesia, Mexico, and Nigeria. The conclusion is that all of the agencies sending craft into space have the capability of conducting controlled descents of rockets and their components, but choose not to do so due to the costs involved.