’Zombie’ satellite runs amok in Earth’s orbit
2010 05 11
By Peter B. de Selding | CSMonitor.com
The out-of-control communications satellite Galaxy 15 is drifting into orbits occupied by other spacecraft.
Intelsat’s Galaxy 15 satellite launched in 2005 with an Ariane 5 rocket in Guyana. The communications satellite stopped responding last month, becoming a ’zombie’ satellite that now threatens other spacecraft. Newscom/File
An attempt to shut down the electronics payload of the out-of-control communications satellite Galaxy 15 has failed, leaving the satellite - which ceased responding to ground commands last month - still in its uncontrolled "zombiesat" drift toward orbits occupied by other spacecraft, the satellite’s fleet operator Intelsat said Tuesday.
Galaxy 15 is closing in on the geostationary orbital slot occupied by another C-band satellite, the AMC-11 spacecraft operated by SES World Skies, and with its stuck-on communications payload will be in a position to cause potentially severe interference with the SES satellite during a two-week period starting around May 23, according to Intelsat and SES estimates.
The unsuccessful attempt to shut down the so-called "zombiesat" – a satellite industry term for failed satellites in orbit - occurred on Monday.
Video from: YouTube.com
In a Tuesday statement in response to Space News inquiries, Intelsat said it is researching other ways to shut down Galaxy 15 once the satellite has passed through the AMC-11 position and enters — for a limited period of time — a stretch of orbital terrain unoccupied by other C-band spacecraft.
"We do not have an additional specific technical attempt identified at this time," Intelsat said in the statement. "But we will not give up, and expect to have other options to pursue at that time. We are now cooperating with other operators and customers to minimize potential service disruptions caused by interference."
Galaxy 15 stopped responding to ground commands April 5 and since then has drifted out of its 133 degrees west longitude orbital slot on an eastward path along the geostationary arc at around 36,000 kilometers above the equator.
After sending between 150,000 and 200,000 commands to the satellite to coax it back into service, Intelsat was forced to scrap its satellite-recovery efforts and to resort, on Monday, to a limited-duration effort to force the satellite to shut down its transponders. This was to be accomplished by sending a stronger series of signals designed to cause Galaxy 15’s power system to malfunction and force a shutdown of the satellite’s payload.
That attempt, which Luxembourg-based, Washington-headquartered Intelsat had viewed as its last, best-understood option for Galaxy 15, was unsuccessful. With the satellite now nearing AMC-11, Intelsat is limited in what it can do besides assure itself of the satellite’s location. "There is no active testing of the payload," the company said in its Tuesday statement.
Sending radio signals strong enough to force a satellite to shut down could pose dangers to other spacecraft in the target area, which is why Intelsat had only a short window of time to "pulse" Galaxy 15 with signals intended to trigger a failure of its power system. That period lasted about 30 minutes on Monday.
"Intelsat fully coordinated with neighboring operators the timing and the effects of this testing to neighboring spacecraft. It is our current understanding that no SES AMC-11 customers were affected by the disabling attempt," Intelsat said.
Intelsat and Luxembourg-based SES have been closely coordinating interference-avoidance options since the initial Galaxy 15 failure, knowing that at predicted drift speeds the satellite will enter AMC-11’s 131 degrees west slot to within 0.5 degrees of AMC-11 on or about May 23.
SES officials say they are devising an elaborate series of maneuvers to create a maximum distance between Galaxy 15 and AMC-11 during the period of maximum threat. While they cannot guarantee that there will be no interference to media customers using AMC-11, the SES officials believe they have the resources, including teleport facilities to reroute traffic, required to minimize the problem during this two-week period.
Continuing its eastward drift, Galaxy 15 will exit the AMC-11 orbital slot starting around June 7, when it is expected to have moved to 0.5 degrees to the east of the satellite.
At that point, a new opportunity will be open to Intelsat as there is no C-band satellite at the next orbital station of 129 degrees west.
What Intelsat might do to precipitate a shutdown remains unclear. Industry officials say the Galaxy 15 problem — a satellite operating at full payload power that is no longer under control — is unprecedented. Intelsat has said it is seeking advice from satellite operators and manufacturers — not just the Galaxy 15 builder, Orbital Sciences of Dulles, Va., but also other companies with more experience with in-orbit problems — on possible options to force a shutdown.
Current estimates are that Galaxy 15 will lose Earth orientation sometime in late July or early August. The exact date cannot be known. But when it loses Earth pointing, its solar arrays will lose their lock on the sun, draining the satellite’s batteries and causing the satellite to shut down on its own.
Once the satellite leaves the vicinity of the AMC-11 and passes through the relatively safe neighborhood of 129 degrees west, it will enter a new neighborhood where it poses an interference threat similar to what AMC-11 now faces. But this time, it is only Intelsat-owned satellites and their customers at risk.
Galaxy 15 will be moving through the operating areas of Intelsat’s Galaxy 13 in mid-July, and is expected to arrive at the Galaxy 14 neighborhood in late July. By mid-August, it will be at the orbital slot of Intelsat’s Galaxy 18.
Article from: CSMonitor.com
NASA: Space junk could threaten astronauts
Satellite collision highlights space-junk threat
NASA and Obama’s budget: the politics and ideals of human space exploration
Big Brothers: Satellites Orbiting Earth (Image)
India loses Moon satellite links
Who Needs Spy Satellites? Google Earth Pinpoints Where Missile Targeted Taliban
U.S. And Russian Satellites Collide
Galileo satellite knocked offline
Spy Satellite Blast, Caught on Tape (Video)
Latest News from our Front Page
Prehistoric Underwater Wall Divides Scientists
2013 12 11
Two camps of scientists have faced off on the issue of the underwater structure known as Bimini Road off the coast of the Bahamas since it was first discovered in 1968.
One camp says it is a 12,000–19,000-year-old man-made structure—flouting the conventional understanding that advanced civilizations only emerged some 5,000 years ago.
The other camp says it is a natural formation.
Author, Researcher Lloyd Pye Dies
2013 12 10
We’re grieved by the sad news that writer and researcher Lloyd Anthony Pye passed away yesterday, December 9, 2013, after a battle with cancer. He was best known for his work with The Starchild Project.
Lloyd was a frequent welcome guest to Red Ice Radio, and we enjoyed the opportunity to speak with him about his work and his writing over ...
Mars May Have Harbored Life 3.6 Billion Years Ago
2013 12 10
Mudstones from Gale Crater, the original landing site of Curiosity, were formed in a lake which may have existed on the planet for hundreds of thousand of years according to scientists.The basin which is 150km wide with a mountain at its centre, could very well have sustained more than one lake approximately 3.6 billion years ago.
Research analysis shows that the ...
Geologists discover ’super volcano’ in Utah, possibly larger than Yellowstone
2013 12 10
Geologists at Brigham Young University have discovered what may be the world’s largest "super" volcano that erupted in Utah’s own backyard.
While there are a variety of volcanoes that blast away in different ways, super volcanic eruptions are the biggest that collapse into large calderas. Yellowstone Park is the remains of one of those calderas and it’s still very much alive ...
Rice grown near crippled Fukushima nuclear plant served to govt officials
2013 12 10
Rice from fields in the Fukushima prefecture, evacuated after the worst nuclear disaster in Japan, will be served to government officials for 9 days in a bid to demonstrate the safety of the country’s most-beloved crop, a local broadcaster reported.
The rice cultivated in several decontaminated fields in the Yamakiya District in Kawamata Town and Iitate Village, two areas designated as ...
|More News » |