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Deployment of the GLONASS constellation
Previous chapter: Uragan satellites
GLONASS-K (left) and GLONASS-M satellites (a.k.a. Uragan) during processing at ISS Reshetnev in Zheleznogorsk circa 2015.
It took more than a decade after the launch of the first Uragan satellite in 1982 to declare the GLONASS network in limited operation in 1993. According to official information, the network reached a full deployment in 1995 with 24 satellites in three different orbital planes. The constellation was declared operational on Jan. 18, 1996, when the satellite launched on December 14 of the previous year was added to the network.
However, giving the economic conditions in the country, the GLONASS constellation began to degrade during the second half if the 1990s, as operational satellites were failing in orbit and new ones could not be launched. In 1996, in the first attempt to revive the system outside its primarily military use, Russia formally offered the GLONASS system to the world community. On Feb. 18, 1999, a presidential decree No. 38-rl ordered the Russian government to sustain and further develop the GLONASS network. The document also declared the Russian space agency to be a second (civilian) customer of the system, along with the Ministry of Defense. (367) Still, by 2001, the number of operational GLONASS satellites in orbit fell to just seven and only six fully operational birds remained in service by the end of that year.
Immediately after the launch of the 30th GLONASS mission in December 2001, which boosted a number of operational satellites to nine, the director of the Rosaviakosmos Yuri Koptev promised to restore the system in the next three years. The previous August, the Russian government allocated 600 million rubles to NPO PM to develop GLONASS-M satellites, which would be the only model to be launched beginning in 2002. To give more flexibility to the system, three satellites were scheduled for launch on Proton and one on the yet-to-be introduced Rus (Soyuz-2)/Fregat rocket.
In 2004, Russian officials promised to have 18 operational spacecraft within the GLONASS network by 2007, which would be a minimum needed for the practical use of the system. The constellation was expected to be completed with 24 spacecraft by 2010. By the end of 2005, Russian official sources said 14 satellites had been active in orbit, not counting three, that were launched on Dec. 25, 2005.
On August 30, 2006, RIA Novosti news agency quoted Minister of Defense Sergei Ivanov promising a full deployment of a 24-satellite GLONASS constellation by 2010. Ivanov's statement preceded a meeting of the military commission on the matter, presided over by a Deputy Prime Minister. Ivanov characterized the network as a vital element of the nation's infrastructure. The meeting also considered mass production of hardware for the end users of the system and related legal issues.
In 2007, the Russian federal budget expected to allocate 11,799.5 million rubles for the GLONASS system. It would be a two-fold increase comparing to the funding in 2006, Russian media said. During 2006, Russian officials said that in the following years, the launch rate of the satellites for the GLONASS network would increase from one to two per year, delivering six new satellites instead of three annually. Two launches, scheduled for 2007 promised to increase the number of operational satellites in the GLONASS constellation from 12 to 18, which could finally enable practical use of the system for navigation sometimes in 2008. However in reality, after the December 2007 launch, the status of the satellites within the GLONASS constellation had been as following:
Only if minimum two satellites designated "under servicing" would return to full operation in 2008 and newly launched satellites successfully join the network, the GLONASS network would reach 18 satellites.
On December 15, 2009, during his meeting with Prime-Minister Vladimir Putin, the head of the Russian space agency Anatoly Permnov promised to complete a GLONASS constellation with 24 operational satellites during 2010, with three launches of nine satellites in February, August and November, the official Russian media reported. Apparently counting a trio of satellites launched the day before, Perminov said that by the end of 2009, the network would include 19 operational satellites. A promotional video produced by Roskosmos for the MAKS-2009 air and space show promised 30 operational GLONASS satellites in 2011. By the time of the 42nd launch of GLONASS satellites in September 2010, 21 satellites were functioning in the system, two were classified as orbital backups and three satellites from the latest 42nd mission were in the process of activation.
Following the December 2010 failure of the 43rd mission to deliver a GLONASS satellite trio, a representative of the TsNIIMash research institute gave following statistics on the constellation status:
At the time, a total of 22 satellites were to be operational by December 2010 and the deployment of the GLONASS constellation to the full capacity was expected in 2011. During that year, plans were revised upwards to include the launch of a standard GLONASS-M trio on the Proton rocket from Baikonur and a pair of GLONASS-M satellites on individual Soyuz-2 rockets from Plesetsk. In addition, two GLONASS-K satellites were scheduled to be orbited by Soyuz-2 during 2011, with the first bird taking off from Plesetsk on February 26.
By the fall of the same year, 23 GLONASS satellites were fully operational, while a pair of GLONASS-K satellites launched February and the latest GLONASS-M launched on October 3 were yet to be drawn into the service. Three more orbiting satellites were officially out of service for maintenance.
In April 2013, the Russian Ministry of Defense reported 29 satellites in the GLONASS network including 23 operational spacecraft and two under a "temporary out of service for technical maintenance. Three additional satellites served as backups and a single GLONASS-K spacecraft was undergoing flight testing.
Interaction with American GPS
Russia discussed various issues related to the development and use of GLONASS in parallel with American GPS and European Galileo systems. According to the head of Federal Space Agency, Anatoly Perminov, in December 2004 Russia and the US discussed the ways of preventing the use of satellite navigation systems by terrorists.
Participation in Europe's Galileo network
Russia also was in talks with the European Space Agency on the possible cooperation on the Galileo navigation network. Details beyond the possibility of launching Galileo satellites onboard Soyuz rockets were not specified.
Cooperation with India
During 2004, Russia discussed the possibility of launching Uragan satellites onboard Indian rockets, in exchange for this country's access to navigation data from GLONASS.
Cooperation with China
Number of contacts between Russian and Chinese space officials included discussions of the GLONASS network. On May 24, 2006, Chief of Staff of the Chinese Liberation Army Lyan Guanle visited ground control center of the GLONASS system, according to RIA Novosti. According to the Russian media, China considered the development of its own satellite navigation system, which could involve purchases of the Russian technology.
2004 Dec. 26: Russia sent up a trio of satellites to upgrade nation's global positioning system. A Proton-K rocket with a Block DM (11S861) upper stage, carrying two Uragan and a follow-on Uragan-M satellites blasted off from Baikonur Cosmodrome at 16:54 Moscow Time. The launch had previously been scheduled for Dec. 25, 2004.
2005 Dec. 25: The Proton-K rocket with Block DM upper stage blasted off from Site 81 in Baikonur Cosmodrome on Dec. 25, 2005 at 08:07 Moscow Time, carrying a trio of spacecraft for Russia's global positioning system, GLONASS. The payload included a regular Uragan spacecraft and a pair of upgraded Uragan-M satellites. The launch brought the number of active Uragan satellites to 17, while a fully functional GLONASS network was designed to have 24 spacecraft. However two Uragan-M spacecraft from the latest mission did not enter operational service until August 2006. At the time, there were 15 satellites actively functioning in orbit. During September 2006, three out of eight satellites within the 3rd plane were temporarily deactivated, apparently in anticipation of the launch of three new satellites in December 2006 and required re-arrangement of the constellation. (As many as five satellites were apparently affected during 2006).
2006 Dec. 25: The Proton-K rocket with Block DM-2 upper stage lifted off from Baikonur Cosmodrome on Dec. 25, 2006, at 23:18 Moscow Time, carrying a trio of spacecraft for Russia's global positioning system, GLONASS. According to the official ITAR-TASS news agency, the spacecraft successfully reached orbit at 02:50 Moscow Time on December 26, 2006. The satellites were expected to use their own propulsion systems to reach final operational orbits.
After almost a decade in orbit, one of two ullage motors ejected from the Block DM-2 upper stage during the mission, fragmented into multiple debris on July 27, 2016, at 01:19 GMT, NASA's Orbital Debris Program Office reported. At the time, the object was in a 19,088 by 426-kilometer orbit with an inclination 64.8 degrees toward the Equator. It was the second such accident in 2016, and 46th known disintegration of the ullage motor from Block DM space tug, NASA said. A total of 380 ullage motors were cataloged from 1970 to 2012 and 64 of them are still in orbit.
One of the spacecraft launched during the mission -- No. 715 -- was taken out of service in orbit on June 26, 2017, and on July 3 of the same year was declared to be under investigation by the chief designer, which is a euphemism for ending the operations.
2007 Oct. 26: Less than two months after its failure, the Proton rocket returned to flight, successfully delivering a trio of satellites for the Russian global navigation system, GLONASS. The Proton-K rocket equipped with Block DM upper stage and carrying three Uragan-M (GLONASS-M No. 18, 19, 20) satellites lifted off from Pad 24 at Site 81 in Baikonur Cosmodrome on Oct. 26, 2007, at 11:35:24 Moscow Time. According to a representative of the Russian space agency, Roskosmos, the upper stage successfully delivered all three spacecraft to its nominal orbit with the altitude 19,100 kilometers above the Earth surface and the inclination 64.8 degrees toward the Equator. At 15:07 Moscow Time, satellites successfully separated from the Block DM upper stage. Ground control then conducted two communication sessions with the spacecraft at 15:15 and 15:40 Moscow Time. According to a statement of the satellite manufacturer, NPO PM, on March 27, 2007, this mission was expected in September 2007.
2007 Dec. 25: Russia launched a second trio of navigation satellites aimed to complete the national global positioning system. A Proton M rocket with Block DM-2 upper stage lifted off from Baikonur Cosmodrome on Dec. 25, 2007, at 22:32 Moscow Decree Time. It carried three Uragan-M satellites for Russia's GLONASS navigation network. The mission was designed to deliver satellites into a circular orbit with an altitude 19,137 kilometers above the Earth surface and the inclination 64.8 degrees toward the Equator. According to a press-release of the Khrunichev enterprise, the developer of the Proton rocket, issued shortly after the liftoff, the launch went nominally. The satellites were expected to separate from the upper stage on December 26, 2007 at 02:24 Moscow Time.
2008 Sept. 25: Russia launched trio of navigation satellites for the nation's GLONASS global positioning system. The Proton-M rocket with the Block DM upper stage lifted off from Baikonur Cosmodrome on Sept. 25, 2008 at 12:49 Moscow Time. It carried three Uragan-M (GLONASS-M) satellites, which were successfully delivered into the planned orbit at 16:20 Moscow Time, a representative of the Russian space forces said. The mission was previosuly expected in July 2008.
2008 Dec. 25: Russia launched a second mission of 2008 to complete the national global navigation system. The Proton-M rocket with Block DM upper stage lifted off from Baikonur Cosmodrome on Dec. 25, 2008, at 13:43 Moscow Time. Block DM and a trio of GLONASS-M satellites separated from the booster stage at 13:53 Moscow Time, reaching the initial parking orbit. Two firings of the Block DM upper stage inserted the satellites into a 170 by 19,000-kilometer orbit and then to a circular 19,100-kilometer orbit. The mission was previously scheduled for October and November 2008.
2009 Dec. 14: Continuing a tradition of several previous years, Russia launched an end-of-the-year mission to replenish its navigation constellation. The Proton-M rocket equipped with Block DM-3 upper stage lifted off on Dec. 14, 2009, at 11:38 Moscow Decree Time from Site 81 in Baikonur Cosmodrome. It carried a trio of GLONASS-M satellites. According to Khrunichev enteprise the launch and the separation of the Block DM with its payload from the third stage of Proton launch vehicle 10 minutes later went normally. The satellites were scheduled to separate from the Block D upper stage around three and half hours after the launch, following two firings of the upper stage, Khrunichev said. With three more launches of GLONASS satellites scheduled for 2010, Russia was on track to return the constellation to its full operational capacity for the first time since 1995.
2010 March 2: Russia launched another trio of satellites to replenish domestically built satellite navigation network. A Proton M rocket with Block DM-2 upper stage lifted off from Baikonur Cosmodrome's Site 81 on March 2, 2010, at 00:19 Moscow Time. It carried three Uragan-M satellites, less than three months after a previous batch of spacecraft for the GLONASS constellation was delivered into orbit. It has also been the third launch of the heavy-lifting Proton rocket since the beginning of 2010.
According to Russian space officials, the upper stage with the payload successfully separated from the third stage of the launch vehicle and reached its initial orbit. According to the launch sequence, the separation of the satellites from the upper stage was scheduled for 03:51:51 Moscow Time on March 2, 2010.
The mission was originally planned for August 2009 and later slipped to Sept. 25 of that year. However a failure of the onboard signal generator on GLONASS-M, No. 726, then already in orbit, led to the satellite's shutdown on Aug. 31, 2009. The incident prompted the return of all three satellites for the upcoming mission to the manufacturer and pushed the launch from Oct. 29, 2009, to the beginning of 2010 and then to the February 10-20 period. By the end of January, the mission was rescheduled for March 2010. Two refurbished and one new satellite for the GLONASS network were shipped to Baikonur on January 26, February 3 and February 10, 2010.
2010 Sept. 2: Russia launched the 42nd mission to build its global positioning constellation Thursday. The Proton-M rocket with Block DM-2 upper stage lifted off from Baikonur Cosmodrome's Site 81 on Sept. 2, 2010, at 04:53 Moscow Summer Time, carrying a trio of GLONASS-M satellites. The separation of the payload from the upper stage was scheduled for 08:25 Moscow Time on the same day. A pair of satellites from the 42nd batch would be placed in the so-called 2nd plane of the GLONASS constellation, while one was expected to replace one of the aging satellites. This launch was previously expected at the end of August 2010.
2010 Dec. 5: In a midst of a hectic launch schedule, a Proton M rocket failed during a mission to deliver the 43rd trio of Uragan-M/GLONASS satellites. The launch vehicle lifted off from Pad 24 at Site 81 in Baikonur Cosmodrome at 13:25:18 Moscow Decree Time. According to the initial statement of the Russian space agency, a payload section (which included Block DM-03 upper stage and three GLONASS satellites) separated what was supposed to be the initial parking orbit 10 minutes after the liftoff. However, according to the follow-up official report, the mission's payload was delivered into a wrong orbit.
2011 Feb. 26: A Soyuz-2.1b rocket with a Fregat upper stage carrying the GLONASS-K1 (No. 11) satellite lifted off on Feb. 26, 2011, at 06:07:15 Moscow Decree Time, from Pad 4 at Site 43 the Plesetsk launch site. This was the first time a satellite for the GLONASS constellation flew onboard the Soyuz-2 rocket from Russia's northern launch site. All previous missions in the program originated from the Baikonur cosmodrome in Kazakhstan and were carried by Proton rockets.
A Soyuz-2.1b rocket with a Fregat upper stage lifted off from Launch Pad No. 4 at Site 43 in Plesetsk Cosmodrome on Oct. 3, 2011 at 00:15 Moscow Time. It carried the Uragan-M (GLONASS-M No. 42) satellite for the GLONASS-M constellation of navigation satellites. According to an official representative of Space Forces, Aleksei Zolotukhin, facilities of the nation's ground control network had started tracking the mission at 00:18 Moscow Time. After reaching the orbit and separating from the upper stage of the launch vehicle, GLONASS-M satellite was expected to enter range of ground control stations at 03:53 Moscow Time on October 3, 2011. According to the flight plan, the separation of the Fregat upper stage from the third stage of the Soyuz rocket was scheduled for 00:24:37 Moscow Summer Time, followed by three engine firings by Fregat. The GLONASS-M was scheduled to separate from Fregat at 03:47:15 Moscow Time. The upper stage would then conduct two engine firings to make a deorbiting maneuver.
The launch took place after a one-day delay caused by high winds at the altitude of 7-10 kilometers. The mission was previously planned for Aug. 26, Sept. 25 and Oct. 1, 2011.
On Oct. 10, 2011, ISS Reshetnev announced that the satellite had successfully deployed its solar panels, established orientation toward the Sun and the Earth; its attitude control, thermal control and power supply systems had been checked.
The transition toward the final orbital position had started with the expected arrival to the operational orbit scheduled for October 20. The operational use of the satellite would start in the beginning of November 2011, bringing the number of spacecraft in the GLONASS constellation to 24, said ISS Reshetnev. From that point on, the Russian satellite navigation network would finally reach its full capacity. According to ISS Reshetnev, GLONASS would provide reliable and uninterrupted navigation around the globe.
A Proton-M rocket with a Briz-M upper stage lifted off from Site 81 in Baikonur Cosmodrome on Friday, Nov. 4, 2011, at 16:51:41 Moscow Time (8:51 a.m. EST). The vehicle is carrying a trio of Uragan-M satellites for the GLONASS constellation.
Around 10 minutes after the liftoff, ground control confrimed that the payload section successfully reached an initial parking orbit.
The Briz-M upper stage then conducted four engine firings to complete the mission, while three GLONASS-M (No. 43, 44, 45) satellites were released in their correct orbits.
The launch comes almost 11 months after a high-profile failure of a similar vehicle to deliver the 43rd cluster of three GLONASS satellites. Since then two launches of Soyuz rockets with GLONASS-K and GLONASS-M satellites had been successful.
In December 2010, the 46th mission was moved up in schedule to June 2011 from September 2011, in the wake of the loss of the 43rd cluster of three satellites. In December 2010, industry sources doubted that three Uragan-M satellites could be ready for the June 2011 launch. The mission was delayed from Oct. 25. The launch was later planned for Oct. 30, 2011.
Preparations for launch on Nov. 3, 2011, at 16:55:45 Moscow Time, had been underway, when technical problems required a 24-hour delay.
A Soyuz-2.1b rocket with a Fregat upper stage lifted off from Pad 4 at Site 43 in Plesetsk on November 28, 2011, at 12:25 Moscow Time, carrying a GLONASS-M satellite. The launch and orbital insertion was successful, Russian space agency, Roskosmos, said. The satellite separated from its upper stage at 15:57 Moscow Time and established contact with mission control at 16:03. According to the agency, at present the GLONASS constellation included 23 operational spacecraft, four in the process of activation, two were temporarily out of service, one in reserve and one in flight testing mode.
2013 April 26: After a 17-month break, Russia successfully launched the 48th mission to replenish its global positioning satellite constellation. The liftoff of the Soyuz-2-1b rocket with a Fregat upper stage from Pad 4 at Site 43 in Plesetsk took place as scheduled on April 26, 2013, at 09:23:41 Moscow Summer Time. The vehicle carried a single GLONASS-M No. 47 satellite. Titov Chief Test Space Center of the Russian space forces started tracking the launch at 09:26 Moscow Time and established control over the satellite at 12:55 Moscow Time (also confirmed as a time of separation from the Fregat upper stage).
According to Nikolai Testoedov, the head of ISS Reshetnev, the manufacturer of the satellite, quoted by the official RIA Novosti news agency, this particular spacecraft was designed to serve as a backup scheduled to replace one of the old satellites in 2014, following a series of checks. According to TsSKB Progress, the mission was postponed from 2012, because the satellites in the GLONASS network performed better than expected and no replacement was necessary.
In preparation for the mission, the spacecraft was shipped to Plesetsk on March 25. The assembly of the payload section was completed by April 18 and the launch vehicle was rolled out to the launch pad on April 23, 2013. The mission became the world's 20th orbital launch attempt in 2013 and the 6th launch for the Soyuz family of rockets during the same year.
Russia's Proton rocket crashed less than a minute after its liftoff from Baikonur, Kazakhstan. A Proton-M with a Block DM-03 upper stage lifted off as scheduled from Pad No. 24 at Site 81 in Baikonur Cosmodrome on July 2, 2013, at 06:38:22 Moscow Time (on July 1, 10:38 p.m. EDT). The rocket started veering off course right after leaving the pad, deviating from the vertical path in various directions and then plunged to the ground seconds later nose first. The launch vehicle was carrying three GLONASS-M satellites (14F113 No. 48, 49, 50) in the 49th mission to deploy and maintain the satellite navigation network.
Despite the accident, on July 5, RIA Novosti news agency quoted Russian Vice Prime Minister Dmitry Rogozin as saying that the latest accident would not disrupt operations of the GLONASS network, thanks to redundancy built into the system.
A Soyuz-2-1b/Fregat rocket lifted off from from Pad 4 at Site 43 in Plesetsk on March 24, 2014, at 02:54 Moscow Time carrying a GLONASS-M No. 54 satellite. According to Roskosmos, the spacecraft was scheduled to be released into its orbit at 06:26 Moscow Time, on the day of the launch. The agency then announced that GLONASS No. 54 had been successfully inserted into its planned orbit. ISS Reshetnev, the spacecraft developer, reported that GLONASS-M No. 54 was launched into the 18th position of the third plane within the GLONASS constellation. The 1,415-kilogram satellite was expected to function for seven years in a 19,100-kilometer orbit.
The launch of GLONASS No. 54 was previously expected on March 11. According to Roskosmos, before the deployment of the latest spacecraft, a total of 28 GLONASS satellites were in orbit, including 24 conducting routine operations, three functioning as orbital backups and one undergoing flight testing.
At the same time, ISS Reshetnev announced that four more GLONASS-M satellites were scheduled for launch during 2014. Three of them had already been manufactured and had been in storage at the company and the fourth spacecraft had been undergoing flight testing, ISS Reshetnev said. According to the company, a total of seven GLONASS-M satellites were in different stages of construction.
A Soyuz-2-1b rocket with a Fregat-M upper stage lifted off from Pad 4 at Site 43 in Plesetsk on June 14, 2014, at 21:16:48 Moscow Summer Time, carrying a GLONASS-M No. 55 satellite. According to official Russian media, the launch was a success and the spacecraft separated from the Fregat upper stage at 00:48 Moscow Time on June 15. It then established contact with ground stations as scheduled at 00:53 Moscow Time, the official ITAR-TASS news agency reported.
Western radar detected the satellite in a 19,132.9 by 19,162.9-kilometer orbit with an inclination 64.77 degrees toward the Equator.
ISS Reshetnev, which developed the spacecraft, announced that GLONASS-M No. 55 was launched into the third plane of the GLONASS constellation and was intended to function in the 21st orbital position of the network. In addition to its regular hardware, this satellite carried an experimental transmitter emitting navigational signals in L3 band. The goal of this experiment was to conduct flight qualification of the equipment and the assessment of the accuracy of navigational performance, ISS Reshetnev said.
The GLONASS-M No. 55 spacecraft was expected to be officially identified as Kosmos-2500. Such a designation created a great deal of confusion within the Russian officialdom and among independent observers of the program.
In the aftermath of the launch on June 14, the Commander of the Air and Space Defense Forces, VKS, Aleksandr Golovko said that "this had been the 2,500th military and dual-purpose vehicle launched in the USSR and Russia." He obviously meant to say that it has been the 2,500th satellite in the Kosmos series. Official Russian web sites then misinterpreted this statement as the 2500th launch from Plesetsk. In the meantime, a previously known spacecraft in the Kosmos series had a designator 2498 and, as a result, many outsiders expected the latest payload to be named Kosmos-2499. Thus, identifying the GLONASS-M No. 55 as Kosmos-2500, the Russian military essentially confirmed the existence of a previously unannounced military payload.
Interestingly, just slightly more than a month ago a trio of "ghost" Kosmos satellites was revealed when Kosmos-2495 was launched on May 6, skipping three Kosmos numbers. Two of the missing numbers turned out to be assigned to radar calibration spheres released in December 2013, during the first test launch of the Soyuz-2-1v rocket. The third missing number -- Kosmos-2491 -- was believed to be associated with a passive object detected by Western radar after the launch of three Strela/Rodnik satellites on Dec. 25, 2013. The following launch of the Strela trio on May 23 also produced a similar fragment, which after the launch of GLONASS M No. 55 is practically confirmed to be "missing" Kosmos-2499. The purpose of these two "ghost" satellites remains a mystery.
2014 Dec. 1
Representing the latest upgrade of the Russian GLONASS satellite navigation system, GLONASS-K No. 12 was the second spacecraft in the GLONASS-K series. Both satellites were intended primarily for flight tests, paving the way to the eventual replacement of operational GLONASS-M satellites with GLONASS-K birds.
A Soyuz-2-1b/Fregat rocket lifted off from Pad No. 4 at Site 43 in Plesetsk as scheduled on Dec. 1, 2014, at 00:52:26 Moscow Time (4:52 p.m. EST on Nov. 30). Following a standard launch scenario for GLONASS missions, the Fregat upper stage performed three engine firings successfully delivering the satellite into its operational orbit around 19,100 kilometers above the Earth's surface. After reaching the orbit, the spacecraft received an official designation Kosmos-2502.
Launch schedule for the GLONASS constellation circa 2014-2015.
Russian military successfully launched a navigation satellite to replace its failed predecessor in the nation's GLONASS navigation network. The Soyuz-2-1b rocket lifted off as scheduled from Pad 4 at Site 43 in Plesetsk on February 7, 2016, at 03:21 Moscow Time (7:21 p.m. EST on February 6), carrying the GLONASS-M-51 satellite.
2016 May 29
A Soyuz-2-1b/Fregat-M launched the GLONASS-M No. 53 navigation satellite from Pad 4 at Site 43 in Plesetsk. It was apparently the second of nine-satellite cache of GLONASS-M satellites remaining on the ground after their production had been discontinued. According to Roskosmos, a total of eight GLONASS satellites were slated for launch before the end of 2017.
As of November 2016, the 24-spacecraft GLONASS constellation had only 23 fully operational satellites, however ground controllers hoped to restore all the functions of the GLONASS-K No. 702 satellite launched in December 2014.
During 2016, a pair of GLONASS-M satellites was decommissioned and several others were operating beyond their official life span, the constellation officials said.
At the time, seven GLONASS-M satellites were still available on the ground. The GLONASS launch manifest called for one Proton launch with three satellites and four Soyuz-2 rockets with single satellites during 2017 and 2018.
A complete list of launches in the GLONASS constellation:
The Proton-K rocket with Block DM upper stage lifts off from Baikonur with a trio of Uragan satellites on Dec. 25, 2006, at 23:28 Moscow Time. Credit: Roskosmos
A Proton-M rocket launches a trio of GLONASS-M satellites on Dec. 14, 2009. Click to enlarge. Credit: Roskosmos
A Proton rocket with GLONASS satellites blasts off on March 2, 2010. Credit: TsENKI
Proton lifts off on an ill-fated mission with GLONASS satellites on Dec. 5, 2010. Credit: Roskosmos
A Proton-M rocket sits on the launch pad in Baikonur on Oct. 31, 2011, in preparation for the 46th GLONASS mission. Credit: Roskosmos
A Proton-M rocket shortly before launch with a trio of GLONASS satellites on Nov. 4, 2011. Credit: TsENKI
The Soyuz-2-1b rocket launches GLONASS-M No. 47 satellite on April 26, 2013. Credit: Zvezda TV channel
A Proton rocket crashes with three GLONASS satellites on July 2, 2013.
A Soyuz-2-1b rocket lifts off from Plesetsk with GLONASS-M No. 55 satellite on June 15, 2014.
A Soyuz-2-1b rocket lifts off with the GLONASS-M-51 satellite on Feb. 7, 2016. Click to enlarge. Credit: Russian Ministry of Defense