Most have landed in the sea, though that does not always prevent them being found. Recently, the US announced a piece of an Ariane rocket had been washed up on its shores, while Japan had found a large chunk of a US rocket booster emerging from the surf. Tremayne-Smith said that a mysterious crash in the Highlands last year, which originally provoked mutterings about UFOs, had almost certainly been the return to earth of a Russian upper stage booster rocket. What made the Skylab episode different was that the space station's imminent demise was forecast weeks in advance, allowing plenty of time for panic to build up in the generous swathe of the earth's surface where Nasa predicted it might fall. A similar, more justified anxiety was caused by the predicted crash in 1983 of a Soviet Cosmos satellite - the craft had a nuclear power pack, and parts of it were scattered over northern Canada, where they were laboriously tracked down and gathered in.
Most crashes happen without warning.
In 1997, a pair of objects similar to the two that came down in South Africa barrelled into the ground in Texas. One landed only 50 yards from a farmhouse in Georgetown. Like the South African debris, they were thought to have come from a US Delta II rocket. The world champion at inflicting space debris on its own citizens was the USSR, which rained rocket boosters on its necessarily uncomplaining people from the launch site of its Baikonour cosmodrome in what is now the independent country of Kazakhstan. Near another launch site, Plesetsk in the north-west, falling rocket parts are so common that people have used them to repair country cottages or build sledges.