Glonass navigation system beefed up with Soyuz launch
BY STEPHEN CLARK
Posted: November 28, 2011
Another spacecraft to reinforce Russia's fleet of Glonass navigation satellites lifted off Monday from the Plesetsk Cosmodrome on a Soyuz booster.
The three-stage booster finished its job in less than 10 minutes, leaving a Fregat upper stage to propel the Glonass payload into a 12,000-mile-high orbit with three engine firings.
The Fregat released the Glonass spacecraft at 1203 GMT (7:03 a.m. EST) and Russian officials declared the launch successful.
The Glonass system broadcasts navigation signals to Russian military and civilian users around the world. It is Russia's counterpart to the U.S. Air Force's Global Positioning System.
Glonass M satellites are built by ISS Reshetnev and designed to function for seven years.
The fresh Glonass satellite will join a network of spacecraft at nearly full capacity. Roscosmos, the Russian space agency, reported 23 Glonass satellites were operational as of Nov. 28. Three more satellites launched Nov. 4 were in their commissioning phase before entering service.
According to Roscosmos, two Glonass satellites are undergoing maintenance, a next-generation Glonass K craft is in the midst of flight testing, and one vehicle was an in-orbit spare.
Russia says 24 satellites are necessary provide complete global navigation coverage.
The satellite orbited Monday is the fifth Glonass spacecraft launched since the beginning of October, punctuating a flurry of missions to restore the system to worldwide service. Soyuz launchers carry one Glonass craft at a time, while the larger Proton rocket delivers sets of three satellites to orbit on a single flight.
"With these launches, we started building orbital reserves," said Nikolai Testoedov, director of ISS Reshetnev. "The presence of two backup satellites in each of the three orbital planes provide an opportunity to fill the needs of the system within a few days or weeks, not months or even years, as it was before."
The Glonass constellation is spread among three orbital planes, each designed to contain eight satellites to maximize coverage around the world.
Russia initiated a satellite replenishment program to mend the fragmented Glonass fleet after a funding crisis in the 1990s rendered the Soviet-era program unable to provide even limited coverage of Russian territory.
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