South Koreans, used to getting mobile phone alerts warning of earthquakes or Covid outbreaks, received a more unusual notification Monday (Jan 9) morning, cautioning of danger from above.

The country’s Ministry of Science and ICT sent a nationwide alert that “some debris from a falling US satellite may crash near the Korean peninsula” at around lunchtime. “Please be careful when going out during that time.”

The ministry subsequently said in a statement that the retired spacecraft - Nasa’s Earth Radiation Budget Satellite - was “believed to have passed over the Korean Peninsula, and no special damage has been reported so far”.

The US space agency said last week that the 5,400-pound (2,450 kilo) satellite would likely re-enter the earth’s atmosphere on Jan 8 or 9.

While most of the nearly 40-year-old spacecraft was expected to burn up upon reentry into Earth’s atmosphere, some components were expected to survive and crash to Earth. Nasa had said the risk of harm coming to anyone on the planet was “very low”.

South Korea, however, was taking no chances and utilised its emergency broadcast system to send a message to the nation’s mobile phones.

Most man-made space debris which falls to Earth poses little threat to humans, although some events, like the uncontrolled re-entry last year of rocket boosters used to launch a Chinese space station module, have prompted concerns about the potential for ground strikes.

 - Bloomberg