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Satellite Collision Adds to 'Space Junk' Problem
The space pollution gets worse over time because objects strike one another and spew out smaller fragments, said David Wright, a physicist with the Union of Concerned Scientists. He warned of the danger of a runaway chain reaction.
"The number of debris particles is going to continue to increase for at least two centuries as debris runs into other debris and grinds down the large pieces to smaller and smaller pieces. All of those can be deadly at orbital speeds," Wright said.
For years, satellites in the congested realm of low Earth orbit have silently passed near one another at eye-blink speed.
Unlike two pickup trucks barreling toward a crossroads on an open prairie, spacecraft operate in three spatial dimensions. Space is big, as the experts say. Thus the odds of any particular satellite hitting another are remote. But over time, with enough spacecraft and enough pieces of spacecraft, the chances of a collision -- somewhere -- increase.
Iridium, the Bethesda-based satellite services company, had 66 working satellites in its "constellation" as of Tuesday morning, plus eight spares, company spokeswoman Liz DeCastro said.
According to Insch, the company contacted the military Tuesday and said that it had lost contact with a satellite.
The military's Space Surveillance Network uses 29 sensors scattered across the globe. Most are radar-based, but a handful use telescopes.
The sensors scanned the sky for the Iridium and quickly saw signs of something amiss.
"The first active radar that looked at it got returns on multiple pieces, what we call a multiple head count," Insch said.
The next step was to retrace the path of the satellite. That quickly produced evidence that the Iridium had crossed paths with the Cosmos.
A radar search for the Cosmos then turned up more debris.
"At that point we put 2 and 2 together and said, you betcha, there's been a collision in space," Insch said.
Johnson said that four or five satellites a day pass within 300 yards of debris or some other satellite. For half a century, there were close calls but nothing worse. The crowding of space has tilted the odds, however.
"It's like winning the lottery. Your odds of winning the lottery are very, very low, but the chances of someone winning the lottery are much higher," Johnson said.
John Higginbotham, chief executive of Integral Systems, a company that handles command-and-control systems for satellites, said the incident highlights the need for some kind of "global satellite traffic control."
"We need the satellite version of air traffic control," he said. Most countries guard their satellite data closely, he said, and there are military and political issues that inhibit cooperation. But, he added, "all space articles, manned and unmanned, satellites, space station, shuttle launches -- everything is at increased risk."
Late yesterday, Stratcom came up with new numbers for the fragments from the Iridium and Cosmos satellites. The Iridium, Insch said, was in 194 pieces by the latest count, and the Cosmos was in 505.
The debris does not form a cloud, he said, but rather is sprinkled in two thin trails that now circle Earth.