Chinese rocket’s chaotic fall to Earth highlights problem of space junk

China has played down fears that its Long March 5B rocket could hit a populated area or a plane in flight but there is no shortage of problem debris in orbit

Sometime this weekend the upper stage of a Chinese Long March 5B rocket will plunge back to Earth and most of it will burn up on re-entry - but perhaps not all.

Military experts in the US expect the booster stage to come down on Saturday or Sunday, but have warned it is difficult to predict where it will land and when and how much material might hit the ground - or if it could knock a plane out of the sky.