WASHINGTON — U.S. Strategic Command is tracking more than 500 pieces of debris from a Russian rocket upper stage that broke up in Earth orbit Oct. 16, according to a spokeswoman for the command.

U.S. Strategic Command is tracking more than 500 pieces of debris from a Russian rocket upper stage that broke up in Earth orbit Oct. 16, according to a spokeswoman for the command.

In an Oct. 25 interview, U.S. Navy Lt. Cmdr. Stephanie Murdock said the debris poses a risk to most objects in low Earth orbit. The number of objects is “expected to fluctuate as we work to characterize the debris field,” she said.

The debris is from the Breeze-M upper stage of a Proton rocket that launched Aug. 6 but failed to place a pair of telecommunications satellites, Telkom 3 and Express MD2, into their proper orbit. The mishap was attributed to a premature shutdown of the Breeze-M stage.

Murdock could not say where the debris field was located, but according to NASA the upper stage was left in an orbit with a perigee of 265 kilometers and an apogee of 5,015 kilometers, with an inclination of 49.9 degrees relative to the equator.

In the October issue of its Orbital Debris Quarterly News publication, NASA said the upper stage measured 4 meters by 2.65 meters and was carrying more than 5 metric tons of propellant. The article expressed concerned that the upper stage might explode, as did two Breeze-M upper stages in 2007 and 2010 following similar flight malfunctions.

The article noted that the Telkom 3 and Express MD2 satellites were left, fully fueled, in orbits similar to that of the Breeze-M. Following other Proton mishaps that occurred in recent years controllers either guided their spacecraft into the atmosphere for a destructive re-entry or in one case were able to raise the satellite to its proper orbit, the article said.

“No decision has yet been made regarding the fates of Telkom 3 and Express MD2,” the article said. Telkom 3 is owned by PT Telekomunikasi of Indonesia; Express MD2 is owned by the Russian Satellite Communications Co. of Moscow.

Nicholas L. Johnson, chief scientist at NASA’s Orbital Debris Program Office at the Johnson Space Center in Houston, said Oct. 26 that the Telcom 3 and Express MD2 are still in orbit with low rates of decay. “With no changes in the spacecraft, they are expected to remain in orbit for 10 years or more,” he said via email.

Warren Ferster is the Editor-in-Chief of SpaceNews and is responsible for all the news and editorial coverage in the weekly newspaper, the spacenews.com Web site and variety of specialty publications such as show dailies. He manages a staff of seven reporters...