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Soyuz MS-18 mission to support ISS expansion lifts off
The first Russian crew exchange aboard the International Space Station, ISS, in 2021, came at a critical junction in the operation of the outpost's Russian Segment. Launching on April 9, the crew members of the Soyuz MS-18 spacecraft are prepared to support the arrival and integration of the MLM Nauka module with the ISS during the 65th and 66th long-duration expeditions on the ISS.
Soyuz MS-18 mission at a glance:
Soyuz MS-18 mission planning
As of 2014, the launch of Soyuz MS-18 was penciled for March 30, 2021, but by early 2020, the start of the mission drifted to April 9, 2021. By that time, Soyuz MS-18 was scheduled to return to Earth with the same crew on September 30, 2021, after 174 days in space.
In the provisional flight manifest prepared by Roskosmos around the end of Summer 2020, the launch of Soyuz MS-18 was moved to April 1, 2021. The mission was then expected to last 195 days and be completed on October 13, 2021.
However, another revision of the ISS flight manifest circa November 2020, settled the launch date for April 9, 2021. In a major change of the flight program, the spacecraft was now scheduled to re-dock from its initial location on the MIM1 Rassvet module to the MIM2 Poisk module on September 25, 2021, to make way for the arrival of the Soyuz MS-19 spacecraft then scheduled for launch on October 5, 2021. After a 12-day overlap with the Soyuz MS-19 mission, Soyuz MS-18 would return to Earth on October 17, 2021, marking the end of Expedition 65 on the ISS.
Finally, according to the February 3, 2021, revision of the ISS manifest (INSIDER CONTENT), the September 25, 2021, re-docking of the Soyuz MS-18 would have the nadir port (INSIDER CONTENT) of the MLM Nauka module as its destination, if the spacecraft arrives before that date. At the time, Nauka's docking with the ISS was scheduled for July 23, 2021. (As of April 2021, the redocking of Soyuz MS-18 from MIM1 to MLM would take place on Sept. 28, 2021.)
The Russian members of the Soyuz MS-18 crew, Oleg Novistky and Petr Dubrov completed training for the manual control of the Nauka module during its final approach to the station should the automated system fail.
Crew changes aboard Soyuz MS-18
As of early 2020, the Soyuz MS-18 crew was expected to include Russian cosmonauts Oleg Novitsky, Petr Dubrov and NASA astronaut Mark T. Vande Hei onboard, but by August 2020, the official plans called for the Russian cosmonaut Andrey Borisenko to replace Vande Hei on the team, as US-built vehicles were expected to take over crew transport operations for the American Segment of the station. Also, around the Fall of 2020, Russian cosmonaut Sergei Korsakov was expected to replace Borisenko on the Soyuz MS-18 crew. However, behind the scene, NASA was negotiating an option with Roskosmos for keeping Vande Hei on the Soyuz MS-18 crew to preserve the principle of having specialists in both segments of the station in each team.
In the meantime, Russian cosmonauts Anton Shkaplerov, Dmitry Petelin and Andrei Babkin comprised the original back-up crew for the mission. However, on January 11, 2021, Roskosmos announced that due to medical reasons, cosmonaut Andrei Babkin had been replaced in the Soyuz MS-18 backup crew with Oleg Artemiev.
On February 9, 2021, NASA announced that it had been "considering obtaining a supplemental seat on the upcoming Spring Soyuz crew rotation mission," (referring to Soyuz MS-18). NASA said it wanted to reserve that seat as a backup for a possible delay or a premature return of the Dragon spacecraft with the second commercial crew scheduled to work aboard the ISS until October 31, 2021, because such situation would leave the American segment of the station unattended. In return, NASA was expected to provide a seat for a Russian crew member aboard one of its commercially procured vehicles. The practice was then expected to continue throughout the ISS project to ensure the presence of mixed crews aboard the outpost at all times.
On March 9, 2021, NASA and Roskosmos officially confirmed that Mark T. Vande Hei would be on the crew as originally planned and NASA astronaut Ann McClain was added to the backup crew, replacing Dmitry Petelin.
In the meantime, the decision by Roskosmos to organize a short trip to the ISS of two non-professional passengers for a movie project with the Soyuz MS-19 mission launching on October 5, 2021, required Dubrov and Vande Hei to give up their seats during the return leg of the Soyuz MS-18 mission on October 17.
After staying in orbit throughout Expedition 66 for almost a year, Dubrov and Vande Hei could return to Earth aboard the Soyuz MS-19 spacecraft. As of February 2021, its landing was scheduled on March 28, 2022.
Preparations for launch
Soyuz MS-18 is being installed on the launch pad at Site 31 on April 6, 2021.
On January 18, 2021, Roskosmos announced that specialists from the Yuzhny space center and RKK Energia had started processing operations with the Progress MS-16 cargo ship and the Soyuz MS-18 crew vehicles. On February 5, radio equipment of Soyuz MS-18's Kurs-NA rendezvous system underwent testing inside the anechoic chamber at Site 254, after which the spacecraft was returned to its processing stand in the same building, Roskosmos said.
The vacuum testing of the Soyuz MS-18 was completed on March 17, 2021, and the checkout of the solar panels with exposure to simulated sunlight was conducted on March 22, 2021.
On March 23, Roskosmos announced that the Soyuz MS-18 would be given the proper name Yu. A. Gagarin to mark the 60th anniversary of the pioneering Vostok mission. A sign with the name Gagarin was added to the exterior of the ship's Habitation Module.
On March 27, members of the primary and backup crews participated in the familiarization training session inside the Soyuz MS-18 spacecraft. On the same day, a meeting of the technical management cleared the Soyuz MS-18 for loading of propellant and pressurized gases, which started on March 29 and was completed on March 30. On the same day, Soyuz MS-18 was returned to the spacecraft processing building at Site 254 and re-installed in its dynamic stand for further operations, which included loading of cargo, the installation of thermal blankets and weighing.
On March 31, the spacecraft was integrated with its launch vehicle adapter serving as an interface with the third stage of the Soyuz-2 rocket. On April 2, 2021, specialists conducted the final visual inspection of the spacecraft, after which it was lowered in horizontal position and rolled inside its payload fairing.
On April 4, the primary and backup crews conducted another familiarization training session inside the Soyuz MS-18 spacecraft, this time in its launch configuration. On the same day, the spacecraft was transferred to the vehicle assembly building at Site 112. Its integration with the Soyuz-2-1a rocket took place on April 5 and on the same day, the State Commission gave the go ahead to the rollout of the vehicle to the launch pad. The rollout operation started on April 6 at 05:30 Moscow Time.
In support of the launch, more than 150 members of the search and rescue team from the Central Military District in Yekaterinburg were deployed in Kazakhstan downrange from the launch site. The force was equipped with more than 20 cars and trucks, including PEM-1, and -2 Sinya Ptitsa all-terrain evacuation vehicles, Mi-8 helicopters, as well as An-26 and An-12 fixed-wing aircraft. In Kazakhstan, rescue teams were stationed at airfields in Karaganda, Baikonur, Zhezkazgan and Arkalyk. Additionally, military rescue teams were activated along the ascent path of the Soyuz MS-18 mission across Russia, at air bases in Uprun, Gorno-Altaisk, Kyzyl and Yekaterinburg.
According to the Russian mission control in Korolev, the Soyuz MS-18 pre-launch operations went according to the following timeline:
Soyuz MS-18 launch profile
Propelled by the simultaneous thrust of the four engines of the first stage and the single engine of the second stage, the rocket headed east to align its ascent trajectory with an orbital plane inclined 51.6 degrees toward the Equator. Slightly less than two minutes into the flight, at an altitude of around 45 kilometers and a velocity of 1.75 kilometers per second, the ship's main emergency escape rocket was jettisoned, immediately followed by the separation of the four boosters of the first stage. Around 35 seconds later, as the vehicle exited the dense atmosphere at an altitude of 79 kilometers and a velocity of 2.2 kilometers per second, the payload fairing protecting the spacecraft split into two halves and fell away.
The second (core) stage of the rocket continued firing until 4.8 minutes into the flight. Moments before the second stage completed its work, the four-chamber engine of the third stage ignited, firing through the lattice structure connecting the two stages. Moments after the separation of the core booster at an altitude of 157 kilometers and a velocity of 3.8 kilometers per second, the tail section of the third stage split into three segments and separated as well.
Following an 8-minute 49-second climb to orbit, the third stage of the rocket released Soyuz MS-18 into an initial parking orbit with an average altitude of 210 kilometers at 10:51:30 Moscow Time.
According to Roskosmos, the parameters of the initial orbit should be as following:
At the time, the ISS was orbiting the Earth at an average altitude of around 419 kilometers.
Soyuz MS-18 followed a two-orbit, 3-hour 25-minute rendezvous profile to reach the International Space Station, ISS. The Russian mission control in Korolev planned a total of six maneuvers with the transport ship's engines, which apparently executed as scheduled:
The timeline of the Soyuz MS-18 rendezvous operations with the ISS on April 9, 2021, was as following:
According to Roskosmos, the spacecraft was scheduled to automatically dock at the MIM1 Rassvet module, a part of the station's Russian Segment, around 14:07:51 Moscow Time (11:07 UTC, 7:07 a.m. EDT) on the day of the launch. The actual docking took place around two minutes earlier, at 14:05:07 Moscow Time, as the two spacecraft were flying over Northern China.
After a series of leak checks, the hatches between the spacecraft and the station were scheduled to be opened according to the following schedule:
In reality, the station side of the hatch was opened around 16:04 Moscow Time, followed by the crew vehicle hatch at 16:20 Moscow Time, as the station was flying over the South Pacific. The arrival of the Soyuz MS-18 crew brought the total population aboard the outpost to 10 people.
Soyuz MS-18 crews:
The official logo of the Soyuz MS-18 mission celebrating the 60th anniversary of Gagarin's mission. Credit: Roskosmos
Soyuz MS-18 is being installed inside the anechoic chamber at Site 254 on February 4, 2021, for radio system tests. Click to enlarge. Credit: Roskosmos
Soyuz MS-18 is being prepared for integration with its launch vehicle adapter. Click to enlarge. Credit: Roskosmos
Soyuz MS-18 is being integrated with its payload fairing on April 2, 2021. Click to enlarge. Credit: Roskosmos
Members of the primary crew (left to right): Mark Vande Hei, Oleg Novistky and Petr Dubrov train inside the space station mockup at Gagarin Cosmonaut Training Center circa March 2021. Click to enlarge. Credit: Roskosmos
Members of the backup crew (left to right): Anne McClain, Anton Shkaplerov and Oleg Artemiev pose in front of the Soyuz MS-18 spacecraft in Baikonur on April 4, 2021. Click to enlarge. Credit: Roskosmos
Final assembly of the Soyuz-2-1a rocket with the Soyuz MS-18 spacecraft on April 5, 2021. Like the spacecraft, the rocket carried an insignia dedicated to the Gagarin's mission. Click to enlarge. Credit: Roskosmos
Soyuz-2-1a launch vehicle with the Soyuz MS-18 spacecraft rolls out to the launch pad at Site 31 in Baikonur on April 6, 2021. Click to enlarge. Credit: Roskosmos
Access gantry are raised around the Soyuz-2-1a launch vehicle with the Soyuz MS-18 spacecraft shortly after their arrival to the launch pad at Site 31 on April 6, 2021. Click to enlarge. Credit: Roskosmos
Crew board Soyuz MS-18. Click to enlarge. Credit: Roskosmos
Soyuz MS-18 lifts off on April 9, 2021. Click to enlarge. Credit: Roskosmos
Separation of the 3rd stage during the launch of the Soyuz MS-18. Credit: Roskosmos
Soyuz MS-18 as seen from the third stage of the launch vehicle during the separation. Click to enlarge. Credit: Roskosmos