When Satellites Collide

Another first in space history:

A commercial satellite owned by a U.S. company was destroyed in a collision with a defunct Russian spy satellite in what NASA said was the first in-orbit spacecraft collision, raising new concerns about the dangers of space debris.

The crash, which happened Tuesday in low-earth orbit, involved one of the satellites owned by closely held Iridium Satellite LLC and a Russian spy satellite that apparently stopped functioning more than a decade ago, according to satellite industry officials.

The collision created two large clouds of debris floating roughly 480 miles above Siberia, and prompted space scientists and engineers to assess the likelihood of further collisions.

The accident could have implications for U.S. space budgets and policy, partly because it comes amid a Pentagon campaign to increase spending on systems to protect U.S. high-tech space hardware by keeping better track of the thousands of pieces of debris and other satellites circling the earth.

As more and more satellites are blasted into orbit, the challenges of keeping them from hitting debris or each other are growing. Military planners also worry about potential enemies jamming, disabling or potentially even ramming U.S. satellites.

Industry officials say Iridium has identified the Russian satellite as a Cosmos 1900 launched in 1993, weighing more than a ton and including an onboard nuclear reactor. A collision could release nuclear residue, though experts have argued for years that the chance of radioactive debris surviving a fall through the atmosphere and reaching inhabited areas is very small.

Even a small piece of debris, moving at nearly 18,000 mph, can be a threat to other objects. That orbit will probably be unusable for many years.