Soyuz-2 rocket launches the 58th GLONASS mission
The Russian military successfully delivered a fresh satellite to replenish the nation's orbital navigation network, despite a lightning strike on the launch vehicle. The 58th mission to deploy and maintain the GLONASS constellation lifted off into rainy skies over Plesetsk Cosmodrome on the Soyuz-2-1b/Fregat rocket on May 27, 2019, at 09:23 Moscow Time (2:23 a.m. EDT). Slightly more than three and a half hours later, the GLONASS M-58 satellite was released into its circular orbit about 19,000 kilometers above the Earth's surface.
GLONASS-M No. 58 mission at a glance:
Preparing the mission
At the start of 2019, Roskosmos and the Russian Ministry of Defense began planning the launch of a Soyuz-2-1b rocket with a Fregat-M upper stage to replace an ailing satellite GLONASS M No. 723 in Russia's GLONASS orbital constellation. According to original plans for the deployment of the GLONASS system, it was expected that one of three missions in the course of the year would deliver previously manufactured Uragan-M satellites for the network, along with two more launches carrying new-generation GLONASS-K and GLONASS-K2 satellites.
A single Uragan-M satellite (a.k.a. 14F113) for the 58th GLONASS mission arrived at Russia's military launch site in Plesetsk from a storage facility of its developer — ISS Reshetnev — on April 13, Roskosmos announced two days after the fact. According to the State Corporation, at the time, a joint team from ISS Reshetnev and Plesetsk was processing the satellite and its separation system from the upper stage. The operations included the installation of the spacecraft on the separation adapter, its integration with the upper stage, followed by autonomous and integrated tests, Roskosmos said.
The delivery of the satellite to Plesetsk marked the start of the launch campaign, which normally lasts around a month, but in the final week of April, the liftoff of the mission was reported to have been postponed from May 13 to May 27.
According to a standard launch campaign with the Soyuz-2-1b/Fregat-M vehicle carrying the GLONASS-M satellites, on-pad operations normally last for three days, including backup time to resolve unforeseen issues. The fueling of the rocket with propellant components normally begins around three hours before the scheduled liftoff time. In case of a delay, a second launch attempt can usually be made within around 24 hours, before a postponement for a longer period is be required.
How GLONASS-M No. 58 was launched
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 were to separate 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 was leaving 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 was to continue firing until around 4.7 minutes in flight, separating moments after the ignition of the RD-0124 engine on the third stage. Moments later, the cylindrical aft section of the third stage was to split into three segments and separate as well. The core stage and the fragments of the aft section 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 southern section of the Pacific Ocean. A warning to air traffic for the area was issued on May 24.
A lightning strike
Several minutes after the planned liftoff time, the official TASS news agency confirmed the fact of the launch. Quoting a Ministry of Defense representative, the announcement said that all pre-launch operations and the liftoff of the Soyuz-2-1b rocket had gone as planned. The assets of the Titov Chief Test Space Center of the Space Forces within the Russian Air and Space Forces, VKS, began tracking the launch vehicle at 09:26 Moscow Time, the Ministry of Defense said. The separation of the payload section, including the Fregat upper stage and a GLONASS-M satellite was confirmed as taking place at 09:32 Moscow Time.
Shortly thereafter, the military TV channel also reported that around 10 seconds after liftoff of the rocket into a rainy and cloudy sky, the vehicle was hit with a lightning strike, but, apparently, suffered no damage. According to a military TV announcer, the rain started around five minutes before the liftoff. Video footage released after the launch showed lightning striking the ascending rocket and the tip of the lightning pole on the launch pad, from which the vehicle had lifted off a few seconds earlier.
Space tug maneuvers
Following the separation from the third stage, the Fregat-M upper stage will use its own propulsion system to deliver the spacecraft to its operational circular orbit more than 19,000 kilometers above the Earth's surface.
The first Fregat's maneuver, lasting just around 20 seconds, will insert the stack into an initial parking orbit and, after a less-than-half-an-hour passive flight, the Fregat will fire its main engine again, this time for around 9.5 minutes. The second maneuver will stretch the orbit to a target altitude of more than 19,000 kilometers, which the Fregat/GLONASS stack will climb for more than 2.5 hours before firing again. The third Fregat maneuver in apogee, lasting just under four minutes, will make the orbit circular, and will be followed by the separation of the satellite around 30 seconds later.
Shortly after the planned separation of the satellite, the Russian Ministry of Defense confirmed that the Fregat upper stage had successfully delivered GLONASS-M satellite into orbit and that ground control had established and maintained stable telemetry link with the spacecraft, whose onboard systems functioned normally. According to the Ministry of Defense, with the launch of the 58th mission, Russian GLONASS constellation included 27 satellites.
Upon the release of the satellite, Fregat is usually programmed to conduct two maneuvers with its attitude-control thrusters, SOZ, to enter a burial orbit above its former satellite passenger.
Within hours after the launch, the NORAD listed two objects associated with the launch in orbit with an inclination around 64.8 degrees toward the Equator. The first appeared to be a satellite in a 19,126 by 19,155-kilometer orbit, while the second object in a 19,152 by 19,509-kilometer orbit could be a Fregat upper stage detected after it had maneuvered away from the satellite:
An artist rendering of the Uragan-M (GLONASS-M) satellite in deployed configuration. Credit: ISS Reshetnev
GLONASS-M satellite. Credit: ISS Reshetnev
Click to enlarge. Credit: Rossiya TV
Soyuz-2-1b rocket with GLONASS M-58 lifts off into rainy sky on May 27, 2019. Click to enlarge. Credit: Russian Ministry of Defense
Click to enlarge. Credit: Rossiya TV
Around 10 seconds after liftoff, the lightning was seen striking the rocket and the launch pad. Click to enlarge. Credit: Novosti Kosmonavtiki
Fregat upper stage boosts Uragan (GLONASS-M) satellite into orbit. Click to enlarge. Copyright © 2017 Anatoly Zak
Fregat and GLONASS-M satellite approach the release orbit. Click to enlarge. Copyright © 2017 Anatoly Zak