Satellite set to plunge to Earth
A redundant satellite is falling back to Earth and experts have no idea where it will come down.
Scientists are no longer able to communicate with the German satellite ROSAT, which orbits the earth every 90 minutes, and estimate there is a one in 2,000 chance it will hit someone.
Parts of the satellite, which is the size of a van, will burn up during re-entry but up to 30 fragments weighing a total of 1.87 tons could hit the ground sometime between Friday and Monday, the German Aerospace Centre said.
"All countries around the globe between 53-degrees north and 53-degrees south could possibly be affected," a spokesman said - a vast swathe of territory that includes much of the earth outside the poles.
The scientific satellite was launched in 1990 and retired in 1999 after being used for research on black holes and neutron stars and performing the first all-sky survey of X-ray sources with an imaging telescope.
The largest single fragment of ROSAT that could hit into the earth is the telescope's heat-resistant mirror, which weighs 1.76 tons.
The satellite will re-enter the atmosphere at a speed of 17,400 mph .
As it nears the Earth in coming days, scientists will be able to more accurately estimate exactly when it will land to a window of about 10 hours.
A dead Nasa satellite fell into the southern Pacific Ocean last month, causing no damage, despite fears it would hit a populated area and cause damage or kill people.
The German space agency puts the odds of somebody somewhere on Earth being hurt by its satellite at 1-in-2,000 - a slightly higher level of risk than was calculated for the Nasa satellite. But any one individual's odds of being struck are 1-in-14 trillion, given there are 7 billion people on the planet.