European scientists are proposing the controlled removal of thousands of dangerous pieces of space debris in the Earth's orbit by sending up robotized missions.

Where space garbage comes from. - ESA

It is estimated that humans have generated 6,000 tons of space garbage, including the proven existence of 13,000 objects larger than 10 centimeters, nearly all left to the universe by the former Soviet republics, United States, China, France, Japan and India.

The fifth European Conference on Space Debris, organized by the European Space Agency, discussed these matters in the German city of Darmstadt, Mar. 30-Apr. 2, including more than 300 experts from 21 countries.

According to the latest ESA estimates, some 600,000 objects larger than one centimeter 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. Defense Department's Space Surveillance Network. The rest of the countries rely heavily on that system for their knowledge of the situation.

Though the Teide Observatory, located on Spain's Canary Islands, and with oversight from the ESA, has been systematically scrutinizing space for debris for a decade.

“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 satellite 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 most of the devices sent to space continue to have fuel remaining after they complete their useful period, and remain that way for a long time.

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, expert with ESA's space operations center, told Tierramérica.

“We fear that there are more and more collisions that generate innumerable fragments, which in turn impact other satellites, and an endless number of collisions are produced in a shorter period. And at some point, space at distances of up to 2,000 kilometers (the area with most satellite paths) will no longer be usable for space travel,” said Krag.

Those clashes are the principal threat to the functioning satellites that are in orbit for purposes that include telecommunications, weather forecasting, navigation, Earth observation and aerospace science. And also for the ships and missions like the International Space Station.

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

The proof of this danger was the Feb. 10 accident, when the U.S. satellite Iridium 33 ran into the Russian Cosmos 2251, 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 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 that stipulate punishment for noncompliance with standards.

There are calls for self-regulation by the governments, and 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 for the first time went beyond that proposal.

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 robotized 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).

In the end, states the conference's conclusions, the costs of losing satellite infrastructure due to collisions would be far higher than the costs of reparative actions.