Soyuz-2 rocket completes the 57th GLONASS mission
The Russian military successfully launched a fresh satellite to replenish the nation's orbital navigation network. The 57th mission to deploy and maintain the GLONASS constellation lifted off from Plesetsk on a Soyuz-2-1b/Fregat rocket on Nov. 3, 2018, at 23:17 Moscow Time. Slightly more than three and half hours later, the GLONASS M-57 satellite was released into its planned circular orbit around 19,000 kilometers above the Earth's surface.
GLONASS-M No. 57 mission at a glance:
Preparing GLONASS-M No. 57
According to Head of ISS Reshetnev Nikolai Testoedov, the status of the GLONASS M-57 mission was discussed during a meeting on Aug. 30, 2018, but the Ministry of Defense had not made an immediate decision on the launch date at the time.
The spacecraft was delivered to the launch site by the beginning of October 2018 and its launch was set for November 3.
Following the launch accident with the Soyuz MS-10 spacecraft on October 11, the GLONASS-M mission remained on schedule for liftoff on November 3.
As of October 30, the launch vehicle was fully assembled and ready for the rollout to the launch pad, which took place on the morning of October 31. On November 1, the rocket and the spacecraft went through the routine integrated tests without major problems. The third work day on the pad was reserved for the closure of any opened issues should they come up in the pre-launch processing. The active preparations for the liftoff would then resume on November 3.
How GLONASS-M No. 57 was launched
The liftoff of a Soyuz-2-1b/Fregat-M vehicle took place on Nov. 3, 2018, at 03:15:17 Moscow Time from Pad 4 at Site 43 in Plesetsk. The rocket carried the GLONASS-M No. 57 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 of 64.77 degrees toward the Equator. The four boosters of the first stage separated around two minutes into the flight and were expected to fall 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 were likely to impact 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 to complete its 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 projected to fall into the Pacific Ocean.
Several minutes after the planned liftoff, the official Russian media confirmed that the mission had been under way. The Russian Ministry of Defense announced that ground assets of the Titov Main Test Center had began tracking the rocket at 23:21 Moscow Time.
Space tug maneuvers
Following the separation from the third stage, the Fregat-M upper stage used its own propulsion system to deliver the spacecraft to the operational circular orbit more than 19,000 kilometers above the Earth's surface.
The first Fregat's maneuver, lasting just around 20 seconds, inserted the stack into an initial parking orbit and after a less-than-half-an-hour passive flight, the Fregat fired again, this time for around 9.5 minutes. The second maneuver stretched the orbit to a target altitude of more than 19,000 kilometers, which the Fregat/GLONASS stack was climbing for more than 2.5 hours before firing again. The third Fregat maneuver in apogee, lasting just under four minutes, made the orbit circular, followed by the separation of the satellite around 30 seconds later.
Upon the release of the satellite, Fregat is usually programmed to conduct two maneuvers with its thrusters to enter a burial orbit above its former satellite passenger. On the morning of Nov. 4, 2018, the Russian Ministry of Defense confirmed that this operation had been successfully completed with two firings of the propulsion system, which had placed the rocket stage in an orbit with an altitude exceeding 19,200 kilometers.
The Russian military also announced that the GLONASS-M satellite had been delivered to the target orbit as scheduled and it had been under control of the ground assets of the Space Forces.
In the meantime, the NORAD listed two objects associated with the launch in the 19,122 by 19,163-kilometer orbit with an inclination 64.8 degrees toward the Equator.
An artist rendering of the Uragan-M (GLONASS-M) satellite in deployed configuration. Credit: ISS Reshetnev
GLONASS-M satellites in various stages of assembly. Credit: ISS Reshetnev
Soyuz-2-1b is being fueled for launch on Nov. 3, 2018. Click to enlarge. Credit: Russian Ministry of Defense
Soyuz-2-1b is ready for liftoff on Nov. 3, 2018. Click to enlarge. Credit: Russian Ministry of Defense
Soyuz-2-1b lifts off on Nov. 3, 2018, with GLONASS M-57 satellite. Click to enlarge. Credit: Russian Ministry of Defense