Cosmic Clutter

8226; During a July 2006 spacewalk, astronauts Piers Sellers and Michael Fossum lost a 14-inch spatula while testing a method to repair the space shuttle.

8226; During a March 2001 spacewalk to mount important equipment on to the international space station, a foot attachment floated away from astronaut Jim Voss. The attachment was to have anchored spacewalkers to space shuttle Discovery8217;s robotic arm. Later in the mission, Discovery8217;s thrusters had to be fired to move the spacecraft to a higher orbit to dodge the piece of space junk.

8226; NASA astronaut Clayton Anderson junked an obsolete tank while on a spacewalk to discard junk. The trash, the size of a refrigerator, plunged into the Earth8217;s atmosphere and burned up over the southern Pacific Ocean on November 2, more than a year after Anderson tossed it off the International Space Station. The 635-kg tank of toxic ammonia coolant slammed into the Earth8217;s atmosphere at an altitude of about 80 km as it flew above the ocean just south of Tasmania.

8226; Last year, China intentionally destroyed its weather satellite, sending at least 1,50,000 bits of orbital debris into space.

8226; On February 20 this year, the US Navy shot down a wayward spy satellite above the Pacific Ocean. Some 3,000 scraps spewed into space, each no smaller than a football.

Messy in space

8226; The trashiest region of space is located about 2,000 kilometers above the Earth8217;s surface. The geosynchronous orbit8212;35,785 km above the Earth8212;also needs a clean-up.

8226; The US Space Surveillance Network counts more than 17,000 bits of debris larger than 10 centimeters. NASA estimates there are over 1 lakh between 1 and 10 cm in diameter.

8226; Space trash in lower orbits usually falls back to Earth within a few years. But those above 1,000 km can circle the Earth for a century.

The danger

8226; Space debris could bang up a working spacecraft along with its crew. NASA says junk falls down on earth about once every day. Most burns up in the atmosphere or falls into oceans or deserted areas. But in 1997, a 550-pound piece of a Delta 2 rocket crashed down in the front yard of a Texas farmhouse.

8226; The large debris can also cause serious damage to a satellite or craft like the International Space Station.

8226; Usually, spacecraft use their tracking systems to dodge objects. But small pieces of orbital debris routinely smash into spacecraft.

Cleaning up

8226; NASA is getting itself a cutting-edge trash dryer. The system blows hot, dry air through wet trash and then collects water from the warm, moist air that emerges. This water can be purified for drinking, and the remaining trash is dry, odourless and inert.

8226; Endeavour has a water recycling system designed to turn astronaut urine and sweat into drinking water.

8226; Other ideas: Space-based laser to push junk into lower altitudes so that they reach Earth faster, a trash-collector vehicle.