DÜSSELDORF, Germany, Apr 14 (Tierramérica) - Tonnes of space garbage is orbiting the Earth and posing serious threats to active satellites and manned space missions, and to astronauts when they conduct space walks outside of their ships.

Where space garbage comes from

Humans have generated an estimated 6,000 tonnes of space garbage, including the proven existence of 13,000 objects larger than 10 centimetres, nearly all left to the universe by the former Soviet Union, the United States, China, France, Japan and India.

More than 300 experts from 21 countries discussed these matters at the fifth European Conference on Space Debris, held by the European Space Agency (ESA) in Darmstadt, Germany from Mar. 30-Apr. 2.

According to the latest ESA estimates, some 600,000 objects larger than one centimetre are swarming in the Earth's orbit. These include inactive satellites, old rockets, fragments of spaceships, and paint chips, left after more than 50 years of human activity in outer space.

The main inventory of space debris comes from the U.S. Defence Department's Space Surveillance Network. The rest of the countries rely heavily on that system for their knowledge of the situation.

But the Teide Observatory, located on Spain's Canary Islands, has also been systematically scrutinising space debris for a decade, with ESA oversight.

"We have already found more than 5,000 objects," astronomer Miquel Serra, head of the Canary Islands' Astrophysics Institute's space debris project, told Tierramérica.

"In a few years, Europe may have catalogued the space debris and won't have to rely on anyone else for information on it," he said.

Since the lift-off of the Soviet Union's legendary Sputnik in 1957, there have been more than 4,600 space launches and some 6,000 satellites put into orbit. But just 800 continue to function with a mission.

Most of the debris comes from explosions, of which there have been about 200, because a majority of the devices sent into space still have fuel left over after they complete their useful lives.

Furthermore, the number of pieces of debris orbiting the planet continues to grow due to collisions.

"The situation is serious. The increase in these objects in space is not regulated," Holger Krag, an expert with ESA's space operations centre, told Tierramérica.

"We fear that there will be more and more collisions that generate innumerable fragments, which in turn impact other satellites," said Krag. "And at some point, space at distances of up to 2,000 kilometres (the area with most satellite paths) from Earth will no longer be usable for space travel."

These collisions are the main threat to the satellites that are in orbit for purposes that include telecommunications, weather forecasting, navigation, Earth observation and aerospace science, as well as for ships and missions like the International Space Station.

At speeds of 40,000 km per hour, even tiny fragments of space debris can cause serious damage to spaceships.

The danger was driven home on Feb. 10, when the U.S. satellite Iridium 33 ran into the Russian Cosmos 2251 satellite, which was out of service. Both were reduced to hundreds of shards, joining the ranks of space garbage.

However, experts consider much more serious the intentional destruction of the Chinese satellite Fengyun 1C with a missile launched from Earth by Chinese authorities in January 2007.

"That one action increased the presence of space debris by 25 percent. It was dramatic, and we are still dealing with the consequences today," Krag said.

On Mar. 12, the crew of the International Space Station had to seek refuge in the Soyuz space capsule for 10 minutes due to the possibility of their vessel's collision with space debris.

There are no binding laws or agreements governing these space activities or stipulating penalties for noncompliance with standards, only calls for self-regulation by governments and for compliance with the directives of the United Nations Office for Outer Space Affairs.

The scientific community has been recommending for more than a decade the controlled re-entry to the Earth's atmosphere of satellites that have lived out their useful lives, so that they can be decommissioned and prevent further collisions and explosions. But the consensus at the recent space debris conference went beyond that proposal for the first time.

The conference conclusions state that it is necessary to plan and implement active measures to remedy the space debris situation, and that there is no other alternative to protect space as a valuable resource for the operation of the indispensable satellite infrastructure.

One of the proposals calls for "the controlled removal of objects from orbit with robotised missions that gather the debris and pull them to an 'orbital cemetery', or even force their fall to Earth in a controlled way," one of the conference presenters, Carsten Wiedemann, of Brunswick, Germany's Institute of Aerospace Systems, told Tierramérica.

The recovery of each of the several thousand satellites in disuse would cost 10 to 20 million euros (between 13 and 26 million dollars).

But in the end, the conference conclusions state, the costs of losing satellite infrastructure due to collisions would be far higher than the costs of reparative actions.

(*This story was originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme, United Nations Environment Programme and the World Bank.) (END/2009)

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