This story was updated at 3:34 p.m. EST.
The planned Friday launch of a new U.S. spy satellite has been delayed by space debris from last week?s destruction of its disabled predecessor, the mission?s launch provider said Wednesday.
Initially slated for a Feb. 29 liftoff from Vandenberg Air Force Base in California, the National Reconnaissance Office?s classified NROL-28 reconnaissance spacecraft will stand down for at least two weeks to avoid the orbiting remains of the destroyed USA-193 satellite, the United Launch Alliance said in a mission update.
?This is a precautionary measure to avoid possible debris from the satellite that was intercepted on Feb. 20,? a spokesperson for ULA, which is overseeing the new satellite?s launch atop an Atlas 5 rocket, said in a Wednesday mission hotline update.
The U.S. Navy cruiser USS Lake Erie launched an SM-3 missile from the Pacific Ocean on Feb. 20 to destroy the defunct USA-193, a school bus-sized classified reconnaissance satellite that failed shortly after its December 2006 launch. The satellite?s demise was a safety measure to prevent its half-ton load of toxic hydrazine rocket fuel from endangering people on Earth, Pentagon officials said.
As of Monday, the military was tracking less than 3,000 pieces of debris, all smaller than a football in size, from 5,015 pounds (2,275 kg) satellite?s destruction, Pentagon officials said. Left unattended, at least half of the satellite was expected to survive reentry to rain down on Earth next month.
?From the debris analysis, we have a high degree of confidence the satellite's fuel tank was destroyed and the hydrazine has been dissipated," said U.S. Marine Corps Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, in Feb. 25 statement.
The satellite, which was also known as NROL-21, was destroyed about 153 miles (247 km) above Earth by a kinetic hit with a missile launched from a point northwest of Hawaii at 10:26 p.m. EST (0326 Feb. 21 GMT).
Military officials said Monday that the majority of the destroyed satellite?s debris has already reentered the Earth?s atmosphere or will do so in the next few weeks. There have been no reports of any debris fragments surviving their fiery atmospheric reentry to impact the ground, they added.
Eager skywatchers, however, did report sightings of what appeared to be the dead satellite?s remains in orbit.
Last week, NASA space operations chief Bill Gerstenmaier said the civilian agency did not believe that debris from USA-193 would hinder the planned March 11 launch of the shuttle Endeavour to the International Space Station (ISS).
"We don't think it'll be a problem, but we'll continue to analyze it to make sure that it's not a problem or a concern to us," Gerstenmaier said on Feb. 20, just after the space shuttle Atlantis landed earlier that day.
The agency activated a backup shuttle runway in California in addition to its primary landing site at the Kennedy Space Center in Cape Canaveral, Fla., in order to land Atlantis and its seven-astronaut crew as soon as possible and give the U.S. military a clear shot at the ailing spy satellite. The shuttle ultimately touched down in Florida after clear weather made its backup landing strip unnecessary.
While the U.S. Navy had modified three SM-3 missiles to make the satellite shot, the spacecraft was successfully destroyed on the first attempt.
As of Monday, the space surveillance systems of the U.S. Strategic Command were continuing to monitor the remaining satellite debris to track any future risk to ground or orbital object, military officials said.
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