22.09.2017

Soyuz rocket delivers the GLONASS-M No. 52 satellite

Approaching the 35th anniversary since the birth of Russia's global navigation network, the nation's military launched the 55th mission to deploy and replenish the GLONASS constellation. The fresh satellite, designated GLONASS-M No. 52, rode a Soyuz-2-1b rocket from the northern spaceport in Plesetsk in the early hours of Sept. 22, 2017.

Previous chapter: Deployment of the GLONASS constellation

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GLONASS M No. 53 mission at a glance:

Preparing GLONASS-M No. 52

Like other spacecraft in the GLONASS constellation, the GLONASS-M No. 52 satellite was developed at ISS Reshetnev based in Zheleznogorsk, Russia. Before being pressed into service in 2017, this particular spacecraft had spent more than two years in storage along with six other satellites serving as spares. In the meantime, the further production of the M-series was winding down to give way to the more advanced GLONASS-K variant.

However the development of the new-generation satellites was severely delayed by Western sanctions introduced after the Russian annexation of Crimea in 2014. As a result, ISS Reshetnev turned to its ground-based spares to replenish the constellation. 

The beginning of the launch campaign for GLONASS-M No. 52 (a.k.a. Vehicle No. 753) immediately followed the retirement of the GLONASS-M No. 715 satellite in orbit. Vehicle No. 715 was launched on Dec. 24, 2006, and after operating for more than a decade was put out of service by ground control on June 26. On July 3, it was declared "under review by the chief designer," which is a euphemism for the end of the satellite's operation. 

At the time, the GLONASS constellation officially listed 27 spacecraft, however two of them were classified as "under review by the chief designer," another one was listed as an orbital spare and one was undergoing testing. As a result, the network had only 23 satellites performing their navigational duties, and was thus one vehicle short of the fully deployed constellation. That number included 12 satellites operating beyond their warranty.

For the routine replenishment of the GLONASS network, a special commission would usually convene to oversee fast-reaction launches of replacement satellites.

On July 5, 2017, the official TASS news agency quoted the head of the ISS Reshetnev Nikolai Testoedov as saying that the new GLONASS-M satellite to replace the retired bird would be launched around the middle of September. According to industry sources, the launch of GLONASS-M No. 52 was first planned for Sept. 6, 2017, but in July 2017, it was postponed until September 22.

On July 27, 2017, a team from NPO Lavochkin, responsible for the processing of the Fregat upper stage before launch, was dispatched to Plesetsk, the company announced in its publication. On July 31, the specialists began electric, pneumatic and other tests of the stage, NPO Lavochkin said.

On Aug. 25, 2017, ISS Reshetnev announced that GLONASS-M No. 52 had been sent to Plesetsk aboard an Il-76 transport plane. At the time, the company said it still had had six GLONASS-M satellites in stand-by mode on the ground for the replenishment of the GLONASS constellation on an "as-needed" basis.

GLONASS-M No. 52 to go to orbit

The liftoff of a Soyuz-2-1b/Fregat-M vehicle took place as scheduled on Sept. 22, 2017, at 03:02:32 Moscow Time from Pad 4 at Site 43 in Plesetsk. The rocket carried a GLONASS-M No. 52 satellite for Russia's GLONASS navigation constellation.

After several seconds of vertical ascent, the launch vehicle headed southeast to reach an orbit with an inclination 64.77 degrees toward the Equator. The four boosters of the first stage separated around two minutes into the flight and fell at drop zone S-19 in the eastern section of the Arkhangelsk Region. Around 45 seconds later, as the vehicle left the dense atmosphere, the payload fairing protecting the satellite split into two halves and its fragments likely impacted the ground at the S-20 drop zone in the Komi Republic. 

The second (core) stage of the rocket continued firing until around 4.7 minutes in flight and it separated moments after the ignition of the RD-0124 engine on the third stage. Moments later, the cylindrical aft section of the third stage split into three segments and separated as well. The core stage and the fragments of the aft section were aimed to fall at the S-21 drop zone in the Omsk Region.

The third stage of the rocket was scheduled to complete its initial powered ascent and separate from the payload section nine minutes and 22 seconds into the ascent. The third stage was then expected to reenter the Earth's atmosphere near the opposite side of the Earth from the launch site and its flaming remnants were to fall into the Pacific Ocean. On September 15, Russian authorities issued a warning to air traffic to avoid a long strip in a remote area of the ocean between New Zealand and Antarctica for the stage impact on Sept. 22 and Sept. 23, 2017.

Several minutes after the scheduled liftoff, the Russian military confirmed that its ground facilities had began tracking the vehicle at 03:06 Moscow Time. According to the Ministry of Defense, the Fregat upper stage and the GLONASS-M satellite successfully separated from the third stage of the launch vehicle at 03:12 Moscow Time on September 22. 

In the meantime, the Fregat-M upper stage used its propulsion system to deliver the spacecraft to its operational circular orbit more than 19,000 kilometers above the Earth's surface. 

Upon the release of the satellite, Fregat was programmed to initiate maneuvers to enter a burial orbit at an altitude of around 19,200 kilometers with several engine firings.

According to industry sources, GLONASS-M No. 52 will be deployed into the second plane of the three-plane GLONASS constellation.

Quelle: RussianSpaceWeb

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Russia’s Soyuz-2.1b rocket takes navigational satellite to designated orbit

The launch took place at 03:03 on Friday from the Plesetsk space center in northern Russia

Russia’s Glonass-M navigational satellite, launched atop the Soyuz-2.1b carrier rocket earlier on Friday, was successfully taken to the designated orbit, the Russian Foreign Ministry’s press service said.

The launch took place at 03:03 on Friday from the Site 43 of the Pad 4 of the Plesetsk space center in northern Russia.

"The medium Soyuz-2.1b carrier rocket took Russia’s Glonass-M navigational satellite to the designated orbit as scheduled," the ministry said.

The launch and orbiting was carried out without any emergency, the ministry said. All systems of the spacecraft operate normally.

Quelle: TASS