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Russia to jump-start its GPS network upgrades

Anatoly Zak, Spaceflight Correspondent
Nov 30, 2014, 9:20 UTC

Sen—The Russian military personnel at the nation's northern space center in Plesetsk is finishing preparations for a long-delayed encore launch of a next-generation navigation satellite.

A Soyuz-2-1b rocket with a Fregat upper stage is scheduled to lift off at 21:52 UTC (4:52 p.m. EST) Sunday, 30 November, from Pad No. 4 at Site 43. (It will already be past midnight local time Monday in Plesetsk).

The Soyuz will be carrying a second copy of the GLONASS-K satellite which was long expected to replace the current GLONASS-M spacecraft comprising Russia's 24-bird satellite navigation constellation.

The 850-kilogram GLONASS-K spacecraft is 565 kilograms lighter than a previous-generation satellite and, more importantly, it has an operational warranty of 10 years, instead of a seven-year life guranteed by its developer, ISS  Reshetnev, for GLONASS-M satellites. The longer lifespan was achieved thanks to an unpressurized structure housing sensitive electronics capable of operating in the vacuum of space.

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A file photo of a Soyuz-2-1b rocket awaiting launch with the first GLONASS-K satellite on board in February 2011. Image credit: Roscosmos

GLONASS-K also sports more efficient solar panels for power supply and expanded band of navigational signals. In the course of its development, GLONASS-K was given additional responsibility to carry KOSPAS-SARSAT transmitters designed to relay SOS signals from ships and aircraft to rescue services, after the Russian space agency, Roscosmos, had scrapped its plans to deploy dedicated satellites for the job.

However all the upgrades to the Russian GLONASS satellites came at a high price. The first GLONASS-K satellite flew in 2011, years later than promised. After its deployment in orbit more technical glitches were discovered in the first and in the follow-on satellite, pushing the launch of GLONASS-K No. 2 around three years behind the original schedule. Its exact launch date remained uncertain as late as the fall of this year.

When, the GLONASS-K No. 2 finally lifts off, three stages of the Soyuz-2-1b rocket are expected to insert the payload section, including the Fregat upper stage and the satellite, on a ballistic suborbital trajectory aligned with an inclination 64.8° toward the Equator. The Fregat will then take over the powered flight, firing its engine for around 19 seconds to reach a 212 by 241-kilometer parking orbit.

After a period of a passive flight, the Fregat will restart its engine for 564 seconds to enter an elliptical 278 by 19,145-kilometer orbit. Upon reaching an apogee (the highest point) of this orbit, Fregat's engine would make a third 224-second maneuver to enter its final nearly circular orbit with an altitude of about 19,140 kilometers. The launch should conclude with the separation of the GLONASS-K No. 2 satellite around three and a half hours after the liftoff. 

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