It is unlikely that debris from space missions, will hit a person when re-entering into the Earth’s atmosphere. But it can happen. Do you remember the ROSAT mission? In October last 2011, the German x-ray telescope satellite fell from space? It safely plunged into the water, at the Bay of Bengal, but a recently disclosed report by the European Space Agency (ESA) shows that, had the satellite delayed its fall just 7 to 10 minutes, it would have hit Beijing.
The satellite was launched on 1990, having fulfilled its purpose on February 1999 and consequently shut down. From that moment on, scientists knew it would re-enter the Earth’s atmosphere, but didn’t know when or where. And there was a problem: due to the solidity of the materials employed in its construction, large amounts of the satellite were likely to remain unburned. It was estimated that a 60% of the spacecraft, which weighed 2.5 tons, would reach the Earth.
The ESA tracks the falling of these satellites, but there is little they can do apart from delivering estimations. In this case, they knew Beijing was in the orbit’s path of the ROSAT, but they needed some months after the re-entry to gather enough information about how high the risk of actually hitting the city had been. According to the German Aerospace Center (DLR), “the probability of someone somewhere on Earth getting injured [for this kind of events] is about 1 in 2,000”. Nothing has happened so far, but is it really a matter of chance?