March 20, 2008

Pentagon: Very Little Debris from Satellite Shooting

Commanders of the U.S. Navy's mission to shoot down a malfunctioning spy satellite last month said there was no substantial new space debris created. 

Rear Admiral Alan Hicks, head of the Pentagon's Aegis ballistic missile defense program, said all but small pieces of debris had burned upon re-entry into the Earth's atmosphere. 

"We thought there would be much larger pieces," he said.

Hicks' made the announcement during a briefing at an annual conference of the U.S. Navy League. His report was the most inclusive to date regarding the mission to destroy the USA-193 satellite, which had been tumbling to Earth in a decaying orbit prior to its destruction.

Hicks explained the mission, describing the 22,000 miles per hour collision between the satellite's fuel tank and the Raytheon ship-launched Standard Missile-3.

"That was a very good thing," he said, while adding that minimizing the debris field was only a secondary goal of the mission.  The mission's primary objective was to protect populated areas from exposure to the satellite's unused hydrazine propellant. 

"We achieved both," he said.

"There's very little left up there of any size. We're down to where there are very  small particles that will burn off as they come down in the atmosphere," Hicks said of the debris from USA-193, adding that no reports had been received of any shards landing on the earth.

The mission took place on February 20,  when the satellite and its fuel tank were destroyed at an altitude of 153 miles over the Pacific Ocean, utilizing part of the Navy's multi-billion dollar ballistic missile shield equipment.

Hicks said the Navy planned and rehearsed for six weeks prior to the mission, with about 250 people involved who utilized a wide range of radar and other sensors to maximize the chance of a bulls-eye while minimizing space debris.

Hicks said the mission's principal lesson was the value of stitching together data from sensors "that normally don't work together on a daily basis."

"When you bring them together, and you can coordinate them, integrate them, you can get a lot more value added,"  he said.

A similar mission was conducted by China in early 2007, when the country shot down one of its older weather satellites from a 530-mile polar orbit. Three months later the U.S. Air Force Space Command said the resulting debris increased the risk of a collision with spacecraft by up to 40 percent in some orbits.

Hicks said that although the USA-193 satellite destruction showed the flexibility of Aegis ballistic missile defense, the mission was a one-time event. Some experts have said the mission was an attempt to show off the anti-satellite capabilities of the Aegis ballistic missile defense program, an opinion denied by officials within the Bush administration.