WASHINGTON -- The $7 billion
Iridium satellite constellation is about to suffer a loss in its family of 72 orbiting craft.
Orbital
debris experts have their eye on Iridium satellite number 79. It should tumble out of Earth orbit and reenter the atmosphere tomorrow. That reentry will be followed about a month later, in mid December, by another Iridium, number 85.
Downtime
The two Iridium spacecraft are derelict satellites, both non-operational, said
Nicholas Johnson, chief scientist and program manager for NASA’s orbital debris office at the Johnson Space Center in Houston, Texas.
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Tomorrow's expected fall from grace of the first Iridium should produce
debris that will reach Earth’s surface. "This is an uncontrollable satellite. It died a long time ago," Johnson told SPACE.com.
"Some pieces are likely to survive. There are about a dozen or so that died early. A lot of those are at higher altitudes. It could be well over a year before another one comes in," Johnson said.
Duck and cover?
William Ailor, head of the Aerospace Corporation’s Center for Orbital and Reentry Debris Studies in El Segundo, California, said the Iridium spacecraft are random reentries. "No one will have a good idea of where or exactly when they’ll come down," he said.
Ailor said that Iridium 79 is predicted to decay on November 29, within plus or minus 5 hours. Iridium 85 is due for a December 17 reentry, plus or minus 5 days or so, he said.
As for any public "duck and cover" worries, don’t get your hard hats out.
NASA’s Johnson said that satellites and upper stages come in all the time.
A study of the Iridium satellite reentries, Johnson said, show they are within a NASA and U.S. government standard of acceptable risk. That is, there is a one-in-10,000 chance of anybody being hurt on the ground by a falling Iridium spacecraft, he said.
Iridium Bankruptcy
Two weeks ago, the U.S. Bankruptcy Court for the Southern District of New York approved a $25 million bid of Iridium Satellite LLC to purchase the operating assets of Iridium LLC and its subsidiaries.
Chairman of Iridium Satellite is Dan Colussy, a veteran of the aviation industry. Iridium Satellite LLC has contracted with the Boeing Company to operate and maintain the satellite constellation.
Motorola, builder and initial operator of the multibillion-dollar constellation of Iridium satellites, has agreed to continue to provide subscriber equipment on "commercially acceptable terms," according to a press statement issued by Colussy’s company on November 15.
Lessons learned
The Iridium story is one of good news and bad, said Carissa Bryce Christensen, space industry consultant, currently working with Futron Corporation in Bethesda, Maryland.
"Iridium achieved some remarkable things. It’s easy to forget that in light of what’s going on now," Christensen said.
The aerospace consultant said that the raising of billions of dollars, the technical know-how in building and operating the Iridium constellation, was extraordinary.
"What they didn’t do was to focus on, analyze and pay attention to the market they could serve," Christensen said. "Iridium had a series of major accomplishments along with some extraordinary failures. Why they failed is baffling," she said.
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