Australian Geographic — May-June 2017

The f inal

junk yard

...where a floating space debris problem is growing.

M

ORE THAN 50 YEARS of human space exploration has

resulted in a potentially hazardous band of debris

orbiting Earth. Travelling at more than 28,000km/h,

this space junk is a growing problem. There are about 500,000

pieces of debris currently in orbit that are each bigger than

a marble – meaning they’re large enough to be tracked – and

countless smaller ones, each of which could damage crewed

spaceships or valuable satellites. Possible solutions include

proposals to drag debris down with magnetic nets or lasers.

So, what sort of junk is out there?

The oldest piece of space

junk orbiting Earth is the

Vanguard 1, the USA’s

second satellite, which

was launched in

1958.

Scientists estimate

there are nearly

objects larger than 5cm

in Earth’s orbit.

10 0 , 0 0 0

Most space junk is

derelict satellites, debris

from collisions of large

pieces of space junk and

stuff left behind from

astronauts, such as faecal

matter and clothing.

In 1965, during the first

US spacewalk, Gemini 4

astronaut Edward White

lost a glove. For about

a month, it remained

in orbit with an esti-

mated speed of

28,000

km/h

Most orbital debris

resides within about

of Earth’s surface.

2000km

Any debris higher than

kilometres will continue

to orbit Earth for a

century or more.

1000

In 2007 China blew up an old

weather satellite with a missile,

creating more than 3000

pieces of debris in an instant.

200

OBJECTS,

most of which were bags

of rubbish, were released

by the Mir space station

during its first 10 years

of operation.

More than

PHOTO CREDITS, CLOCKWISE FROM TOP: SPL CREATIVE / GETTY; NASA; NASA. SOURCES: NASA; ESA; ABC SCIENCE

28 Australian Geographic