MOSCOW — The crash of two satellites has generated an estimated tens of thousands of pieces of space junk that could circle Earth and threaten other satellites for the next 10,000 years, space experts said today.

One expert called the collision "a catastrophic event" that he hoped would force President Barack Obama's administration to address the long-ignored issue of debris in space.

Russian Mission Control chief Vladimir Solovyov said Tuesday's smashup of a derelict Russian military satellite and a working U.S. Iridium commercial satellite occurred in the busiest part of near-Earth space about 500 miles above Earth.

"(500 miles) is a very popular orbit which is used by Earth-tracking and communications satellites," Solovyov said today. "The clouds of debris pose a serious danger to them."

Solovyov said debris from the collision could stay in orbit for up to 10,000 years and even tiny fragments threaten spacecraft because both travel at such a high orbiting speed.

James Oberg, a NASA veteran who is a space consultant, described the crash over northern Siberia as "catastrophic." NASA said it was the first-ever impact between two intact spacecraft — with the Iridium craft weighing 1,235 pounds and the Russian craft nearly a ton.

David Wright at the Union of Concerned Scientists' Global Security said the collision had possibly generated tens of thousands of particles larger than half an inch, any of which could significantly damage or even destroy a satellite.