Space junk a huge environmental challenge, expert warns
Metal and plastic junk hurtling round the Earth at more than 20 times the speed of sound presents one of the greatest environmental challenges facing humanity, a leading British expert has said.
Dr Hugh Lewis believes the growing problem to be a threat to future generations' hopes of living and working in space.
Cleaning up orbital space and turning it into an environment that can be sustainably used "may take years to achieve" with the help of engineers, scientists, lawyers and economists, he says.
Dr Lewis was speaking at the Royal Astronomical Society, London, at the launch of Adrift, a new science and arts project aimed at raising awareness of space junk.
The danger posed by even tiny particles of debris in space was graphically illustrated during British astronaut Tim Peake's mission aboard the International Space Station, when a fleck of paint left a 7mm chip in a window.
An estimated 100 million pieces of space junk are orbiting the Earth, 27,000 of which are larger than 10cm across and are being tracked by the American space agency Nasa and US Department of Defence.
Each piece is travelling at speeds of up to 28,000 km/h (17,398 mph).
Dr Lewis, who heads a group researching space debris at the University of Southampton, said: "Tackling the problem of space debris is one of humankind's greatest environmental challenges, but it is also perhaps the one that is the least known.
"Every day we use and rely on services provided by satellites without ever realising how vulnerable they are. It's not just that satellites can be damaged or destroyed by space debris today or tomorrow, it's that the actions of our generation may affect the dreams and ambitions of future generations to work and live in space."
Nasa defines space debris as "any man-made object in orbit about the Earth which no longer serves a useful function".
Currently the biggest piece of junk flying 225 km (140 miles) above the Earth is Envisat, an Earth observation satellite the size of a double decker bus launched by the European Space Agency in 2002.
Other hazards include a swarm of 2,000 pieces of debris left by the collision in 2009 of a defunct Russian satellite, Cosmo, and a US commercial satellite.
Prospero, the first UK satellite to be launched by a British rocket in 1971, is also still orbiting the Earth.
One ex-Nasa scientist, Professor Donald Kessler, has envisaged a domino effect, with crashing pieces of space junk producing more debris in a continuous cascade.
If the so-called "Kessler effect" ever became a reality it could render future space travel impossible.
Adrift is a three-part project combining film, sound, and an interactive element, enabling people to adopt individual pieces of space junk.
It includes a mechanical art installation created by Bafta-winning composer and artist Nick Ryan, Machine 9, which will transform the movement of space debris into sound in real time.
The Adrift exhibition is due to open next year at Hackney House in London.