Pieces of a retired German satellite hurtling toward the atmosphere may crash to earth this weekend, the German Aerospace Center said Thursday.

Scientists have now honed their initial estimate of when the satellite would hit from a span of four days to either Saturday or Sunday. As it nears, they will eventually be able to estimate impact within a window of about 10 hours.

Parts of the satellite, which is the size of a minivan, will burn up during re-entry but up to 30 fragments weighing a total of 1.87 tons (1.7 metric tons) could crash into the Earth with a speed of up to 280 mph (450 kph).

The satellite orbits the Earth every 90 minutes and scientists can only say that it could hit Earth anywhere along its path, between 53-degrees north and 53-degrees south — a vast swath of territory that includes much of the planet outside the poles.

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