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Soyuz launches GLONASS-M No. 53 satellite
Russian military launched a navigation satellite from its northern spaceport in Plesetsk to replenish the country's GLONASS constellation. It was the 54th launch into Russia's dual-use constellation since the beginning of its deployment in 1982.
A Soyuz-2-1b rocket launches GLONASS-M No. 53 satellite on May 29, 2016.
GLONASS M No. 53 mission at a glance:
At the beginning of 2015, the GLONASS constellation functioned so well that in March of that year, Roskosmos decided to cancel a planned replenishment launch of the Proton rocket with a trio of GLONASS satellites No. 52, 53 and 56. The launch of a single GLONASS-M No. 51 satellite on a Soyuz-2-1b rocket from Plesetsk, which was previously planned in the 2nd quarter of 2015, was instead penciled for September. However within a month, the situation turned to the worse.
On April 13, 2015, a relatively new Kosmos-2478, launched on Nov. 28, 2011, failed in orbit, requiring to take out of retirement Kosmos-2419, which had had serious technical problems of its own. Launched on Dec. 25, 2005, with an official operational life span of seven years, Kosmos-2419 outlived its warranty by three years. The largely crippled spacecraft orbited in Plane 3 of the three-plane constellation. Despite all efforts to keep the satellite alive, Kosmos-2419 had to be declared dead on October 17.
Nine days later, on Oct. 26, 2015, ISS Reshetnev, the GLONASS developer, announced that the company had began preparations for the launch of the GLONASS No. 51 satellite.
On January 18, 2016, Roskosmos announced that the GLONASS constellation had consisted of 27 spacecraft, including 23 satellites in operation, two spacecraft undergoing flight testing and two "under investigation by the chief designers." The latter was a known euphemism for all but dead spacecraft. The statement essentially confirmed that the 24-satellite constellation was missing one operational vehicle. Roskosmos promised the launch of a fresh GLONASS-M satellite in February 2016, which would be the first vehicle out of a nine-satellite cache stored at ISS Reshetnev in Zheleznogorsk.
The satellite was successfully launched on February 7, 2016, with up to two more single launches on Soyuz still expected before the end of 2016. In the meantime, a triple launch on Proton was ruled out for at least several months.
According to Roskosmos, a total of eight GLONASS satellites were slated for launch before the end of 2017.
Preparing GLONASS-M No. 53
The GLONASS-M No. 53 satellite was shipped to Plesetsk on April 22, 2016, however, in the first half of May, the launch was postponed from May 21 to May 29.
On May 25, Russian authorities issued a warning to pilots closing an area southeast of Plesetsk. It was associated with the site S21 northeast of the city of Tobolsk.
Liftoff of a Soyuz-2-1b/Fregat-M vehicle was scheduled for May 29, 2016, at 11:44:37 Moscow Time (08:44 GMT, 4:44 a.m. EDT) from Pad 4 at Site 43 in Plesetsk. (After the completion of the flight, industry sources confirmed the launch time as 11:44:35.411 Moscow Time).
After several seconds of vertical ascent, the launch vehicle was to head southeast to reach an orbit with an inclination 64.77 degrees toward the Equator. Four boosters of the first stage were expected to separate around two minutes into the flight and fall at drop zone S-19 in the eastern section of the Arkhangelsk Region. Around a minute later, as the vehicle passes the dense atmosphere, the payload fairing protecting the satellite was to split into two halves and its fragments were likely to impact the ground at the S-20 drop zone in the Komi Republic.
The second (core) stage of the rocket was to continue firing until around 4.7 minutes in flight and was expected to separate moments after the ignition of the RD-0124 engine on the third stage. Shortly thereafter, the cylindrical aft section of the third stage was to split into three segments and to separate as well. The core stage and the fragments of the aft section was expected to fall at the S-21 drop zone in the Omsk Region.
The third stage of the rocket was expected to complete the initial powered ascent less than nine minutes into the flight.
After entering an initial orbit, the Fregat-M upper stage was to be used to deliver the spacecraft to its release orbit more than 19,000 kilometers above the Earth's surface at 15:16 Moscow Time. At 15:36 Moscow Time, Fregat was scheduled to initiate maneuvers to enter a burial orbit at an altitude of around 19,200 kilometers, which were later reported as successful after several engine firings.
NORAD radar detected the latest GLONASS satellite in a 19,148 by 19,491-kilometer orbit with an inclination 64.8 degrees toward the Equator.
According to industry sources, Uragan-M No. 753 was to be deployed at Position 11 within the second plane of the three-plane GLONASS constellation.
Around six minutes after the scheduled launch time, the official Russian media, quoting Ministry of Defense, reported that the liftoff took place at 11:45 Moscow Time. Lt. General Aleksandr Golovko, the Commander of the Space Forces within the Russian Air and Space Forces, oversaw the launch operations in Plesetsk and the Titov Chief Test Space Center began tracking the vehicle, the TASS news agency said.
According to Roskosmos, the launch took place at 11:44 Moscow Time and the payload section separated from the third stage of the Soyuz rocket nine minutes into the flight. The Fregat upper stage then initiated the delivery of the satellite to its prescribed orbit, with the separation of the payload scheduled at 15:16 Moscow Time (12:16 GMT, 8:16 a.m. EDT), Roskosmos said.
The Russian Ministry of Defense also announced that the GLONASS-M No. 53 had established communications with ground control and all systems onboard the satellite had functioned properly. The official Russian monitoring service, SKDM, also listed the launch of GLONASS-M No. 753 as Kosmos-2516 and registered the liftoff time as 11:44:35 Moscow Time.
Within 24 hours after the launch of GLONASS-M No. 53 on May 29, the TASS news agency reported that the RD-0124 engine on the third stage had shut down prematurely during the launch. Fortunately, the flight control system onboard the Fregat space tug detected the problem and compensated for the lack of performance of the third stage with an extended firing of the Fregat's own propulsion system, enabling the stack to reach an initial parking orbit and thus salvaging the mission.
By June 2, sources on the web forum of the Novosti Kosmonavtiki magazine reported that the RD-0124 engine had shut down around five seconds earlier than scheduled as the vehicle had been flying on a ballistic arch just short of orbital speed. However, the flight control system onboard the Fregat space tug, which takes over the powered flight after the separation from the third stage, is designed to measure the actual parameters of the ascent path and to adjust its own engine operation as necessary to reach an initial parking orbit.
Due to premature shutdown of the third stage, computers onboard Fregat received "Avariya" (accident) command from the launch vehicle instead of the GK-3 command (Main Command No. 3), which marks the nominal engine cutoff. As a result, the flight control system onboard Fregat recalculated its first maneuver in near-real time and commanded the main engine to fire 1.5 times longer than planned in order to reach the prescribed parking orbit.
The further orbital insertion apparently went as scheduled.
Design variations in the third stage of the Soyuz rocket.
Read much more about the history of the Russian space program in a richly illustrated, large-format glossy edition:
An artist rendering of the Uragan-M (GLONASS-M) satellite in deployed configuration. Credit: ISS Reshetnev
The Uragan-M No. 53 satellite for the 54th launch into the GLONASS constellation leaves its manfuacturing site in Zheleznogorsk for the Yemelyanovo airfield before its delivery on an Il-76 aircraft to Plesetsk in April 2016. Click to enlarge. Credit: ISS Reshetnev
A Soyuz-2-1b rocket lifts off with GLONASS-M No. 53 satellite on May 29, 2916. Click to enlarge. Credit: ISS Reshetnev