Astrophysics Professor talks junk!

Posted by mjs76 at Nov 17, 2010 10:20 AM |
Professor Martin Barstow, Head of our College of Science and Engineering, was interviewed in yesterday’s Daily Telegraph as part of a feature on the dangers of orbiting debris or ‘space junk’.

Ever since October 1957, when the Soviet Union became the first country to place a satellite in orbit, more and more stuff has been hurled up into space every year and only a certain percentage of it falls back to Earth and burns up in the atmosphere. As the space around Earth gets more crowded, the chances of space junk damaging operational spacecraft increases – and indeed this has already happened.

It’s not just the obvious, big lumps of machinery that need to be avoided, like dead satellites and spent rocket boosters but also things like nuts and bolts and spanners dropped by astronauts. Ed White somehow managed to lose a glove during the first NASA spacewalk in 1965 and that’s probably still up there somewhere.

It is estimated that there are about 600,000 items in Earth orbit of which about 19,000 are being tracked and could potentially be avoided, which leaves a lot of unknowns. There are also million of minute items, such as flakes of paint or tiny pieces of solid rocket fuel. However, the velocity of these means that any collision, even with something very thin and light, generates enough energy to vaporise the object. This is one reason why satellites often have a layer of foil on the outside.

However, as Martin, who is Professor of Astrophysics and Space Science in our Department of Physics and Astronomy, points out, “Even dust particles travelling at very high velocities can enter and knock out a satellite if they hit the wrong part."