http://www.networkworld.com/news/2009/021209-iridium-satellite.html
Iridium calls may suffer outages from satellite crash Iridium is moving a spare into place after collision with Russian military satellite By Tim Greene Network World 02/12/2009 Iridium customers may experience brief sporadic outages in their satellite phone services through tomorrow as the company recovers from a collision between one of its communication craft and a dead Russian military satellite. Until Iridium can move a replacement satellite into the position held by the one destroyed in the crash, the remaining 65 satellites and four ground stations in Iridium’s network will route around the problem, a spokeswoman says. The provider has eight spare satellites flying in lower orbit than their production constellation, and the spares can maneuver up to replace ones that become inoperable, she says. In addition the company has two groundstations for sending and receiving traffic between the satellite and the Earth, plus two backups. “It’s a very flexible network,” she says. Each satellite has four crosslinks with other satellites in the production constellation, which enables routing traffic around failures and congestion. Related Content Iridium uses Boeing contractors to monitor and update the satellites, the spokeswoman says. Iridium satellites orbit the Earth from pole to pole with some flying in one direction some in the other. They communicate with satellites immediately in front and behind them and to either side that are flying in the same direction. Independent groups that monitor satellite traffic say they could tell that the Iridium satellite and the Russian satellite were going to pass near each other, but because of other satellite traffic and space junk floating in the area, could not actually predict collision, according to published reports. Some of the debris was created when China blew up one of its own defunct weather satellites nearby with a missile in 2007. The Iridium satellite was orbiting 485 miles above the arctic, which is high enough that the atmosphere doesn’t slow them down and shorten their usable life but low enough to provide high-quality signals. -- ================================ George Antunes, Political Science Dept University of Houston; Houston, TX 77204 Voice: 713-743-3923 Fax: 713-743-3927 Mail: antunes at uh dot edu *********************************** * POST TO [email protected] * *********************************** Medianews mailing list [email protected] http://lists.etskywarn.net/mailman/listinfo/medianews
