Retired teacher solves Chinese space puzzle

Down to Earth: Rogue satellite will crash from the skies at midday on 12 March (give or take 18 hours), says amateur expert

CHARLES ARTHUR

Science Correspondent

A rogue Chinese satellite is expected to crash to Earth early next week, and some of the best people in the field are tracking its unpredictable downward spiral. They include the US Space Command, the European Space Agency (ESA), the UK Defence Research Agency and Geoffrey Perry, of course.

Judging by his track record, Mr Perry - a retired physics teacher now living in Cornwall - probably has the most accurate prediction for the satellite's eventual landing time. "Midday on the 12th of March [Tuesday], plus or minus 18 hours," he told The Independent yesterday. By contrast, ESA's latest official estimate is 4am on the 12th - plus or minus 24 hours.

Mr Perry's relies on long experience and superior techniques. He observes satellites at dusk, sitting in his garden with binoculars and a stopwatch, and listens in to their radio bleeps from his home. Explaining his latest forecast, he said: "I get US radar data which is collected by Fylingdales. I take the last six sets of data, fit a parabola to them, calculate the rate of decay, correct for the semi-annual variation, and add that to the date. Perfectly straightforward."

Mr Perry's experience predates the ESA, and spans more than 30 years. For much of that time he taught at Kettering Grammar School for Boys where he found the dawning of the space age provided a means of fascinating pupils - and of scooping the rest of the world.

In 1966, using pounds 25 worth of radio equipment, he and his pupils noticed that some of the newly launched Soviet satellites had a different orbit from others. From that, they deduced that the Soviets were using a new launch site - a fact the USSR would only admit to publicly twenty years later.

In December 1973 they tracked the successful landing of Soyuz-13 and issued their data, which was precise and correct, to the world an hour before the Soviets. "Things like that fire kids' imaginations," he recalled yesterday at his home in Bude. " I remember one of them saying, 'It beats pouring iron filings over a magnet, or putting hot rivets into a calorimeter'."

The grammar school has since closed, but Mr Perry, now 68, has managed to keep alive the principle of the "Kettering Group" - as it became known. A worldwide network of amateur observers have been in touch for years, swapping information by telephone, fax and now e-mail.

His inspirational methods also run in in the family. His daughter is now the head of physics at Malvern Girls' School - encouraging pupils to follow the satellite's downward path.