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Integrating the MLM Nauka with ISS

To support the addition of the MLM Nauka module to the International Space Station, the Russian crew members aboard the outpost had to perform many chores preceding the docking of the 20-ton spacecraft, which would increase the size and mass of the Russian Segment by almost a third. Moreover, once the module is in place, Russian cosmonauts were expected to conduct up to 11 spacewalks to fully plug all the systems of the new room into their home in orbit. The total in-orbit time required to integrate Nauka was expected to reach 2,000 work hours!

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A computer-generated visualization of the MLM module's docked at the ISS.

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The first 12 months of the MLM-U Nauka mission were considered to be a period of flight testing, starting with the launch, the autonomous flight and docking with the station. That period also included the integration of the module with the Russian ISS Segment highlighted by the installation of the Science Airlock, ShK, the Add-on Radiator Panel, RToD, (INSIDER CONTENT) and the Means of Attachment of Large Payloads, SKKO. Additionally, all systems of the module and its interfaces with the Russian Segment would have to be tested. Finally, the module would have to be outfitted with payloads and instuments and various emergency modes and operations aboard the spacecraft had to be tested and put in place. The flight test program for the MLM-U spacecraft was officially approved in 2018.

The complex work to integrate the MLM Nauka module with the rest of the station can be sub-divived into three major phases:

Evolution of Nauka's integration timeline

Due to multiple delays with the preparation of the MLM Nauka for launch during the 2010s, Roskosmos had to work on the "shifting sand" for a number of years constantly re-scheduling the complex process of integration of the module between different ISS flight manifests and from one ISS crew to another. Roskosmos officials also had to take into the account the changing situation on the Russian Segment, for example, the early 2016 decision to reduce the Russian crew aboard the outpost from three to two people due to financial problems.

The reduced crew allowed Russia to save one trip of the Progress cargo ship to the station every year. With three cosmonauts living on the ISS again, Russia would have to send four cargo ships to the station during that year.

On February 12, 2016, RKK Energia officially informed Roskosmos that a three-person Russian crew would be needed aboard the ISS ahead of the MLM arrival.

On September 7, 2016, the State Commission overseeing the project issued the official decision No. 280GK-16 mandating the increase of the Russian crew aboard the ISS back to three ahead of the arrival of the MLM module. At the time, MLM was scheduled for launch in December 2018.

The 2017 launch scenario

On September 22, 2017, RKK Energia also informed Roskosmos that four Progress cargo missions would have to be dispatched to the ISS during 2019, when the MLM was expected to reach the station.

At the time, the schedule prepared by RKK Energia pushed the launch of MLM Nauka to March 21, 2019. According to that plan, after a nine-day autonomous flight, the spacecraft would dock at the nadir (Earth-facing) docking port of the Zvezda Service Module, SM, a part of the Russian Segment of the station, on March 30, 2019.

According to the September 2017 draft documents, the preparations for the addition of the long-awaited module were scheduled to begin on September 8, 2018, with the launch of the three members of Expedition 57 crew aboard the Soyuz MS-10 spacecraft. At the time, the launch was expected to mark the first time since October 2016 that a Soyuz would lift off with more than one Russian cosmonaut. Two Russian cosmonauts, a veteran Aleksei Ovchinin and a rookie Nikolay Tikhonov were to be onboard, according to that schedule. They were to be accompanied by NASA astronaut Nick Hague. The trio was to work on the station until Feb. 24, 2019, and would not actually see the Nauka at the station but would lay the ground work for its arrival.

The same plan also saw the launch of Soyuz MS-11 on November 7, 2018, with Russian cosmonaut Oleg Kononenko, US astronaut Serena Auñón-Chancellor and Canadian David Saint-Jacques onboard. On March 7, 2019, they would be joined in orbit by the crew of Soyuz MS-12 with a yet to be assigned pair of Russian cosmonauts and one US astronaut. These two crews, including three Russians, were to be onboard the ISS during the hectic operations to receive the Nauka.

According to the September 2017 timeline, when Proton rocket would launch the new module from Baikonur Cosmodrome in Kazakhstan, its destination port on the Zvezda Service Module was expected to be occupied by the Pirs Docking Compartment, SO1, which has been located there since 2001. To discard the old module, it was to be undocked along with the Progress MS-10 spacecraft that would have been attached to its free docking port since October 2018. Because Progress vehicles has ability to maneuver, it was to be used to direct Pirs into the Earth's atmosphere to burn up.

According to the scenario considered around October 2017, the launch of the Prichal Node Module along with the Progress-MS-UM spacecraft was set for November 14, 2019. Two days later, the Progress/Node stack was to dock to the nadir (Earth-facing) port of the MLM Nauka module. Around a month later, the propulsion section of the Progress-MS-UM spacecraft was to separate from the Node, making it available for other ships visiting the ISS.

All these plans were yet to be approved by Roskosmos and the by the Russian government, but it had never materialized due to new lengthy delays with the launch of the module.

New 2019 timeline

According to the plans formulated around October 2019 (Insider Content), the arrival of the MLM Nauka module to the ISS was expected in December 2020, during the 64th long-duration expedition aboard the ISS. This time, the responsibility to receive the module aboard the Russian Segment was fallen on three Russian crew members scheduled for launch aboard the Soyuz MS-17 spacecraft on October 14, 2020. As of October 2019, the Soyuz MS-17 crew included the commander Anatoly Ivanishin, flight engineer Ivan Vagner and a yet-to-be selected cosmonaut.

Possibly, Roskosmos delayed the assignment of the third member of the Soyuz MS-17 crew in anticipation of more certainty with the MLM launch date.

Because the Nauka module was expected to replace the Pirs Docking Compartment, SO1, on the nadir port of the Zvezda Service Module, the cosmonauts planned to do a number of removals and re-arragnements aboard SO1 ahead of Nauka's arrival.

Following the docking of Nauka, the Soyuz MS-17 crew would open hatches into the newly arrived spacecraft, conduct its activation and unload the cargo hitchhiked to the station.

The original 2021 launch timeline


Testing of spacewalking techniques with a full-scale mockup of the MLM module and other components of the Russian Segment inside the renovated neutral byouncy facility of the Gagarin Cosmonaut Training Center in May 2020.

The latest timeline in place in June 2021 (Insider Content), called for the launch of the MLM Nauka module on July 15, 2021, at 20:16 Moscow Time, during Expedition 65. In case of the on-time launch, the Progress MS-16 spacecaft would depart the ISS on July 17, 2021, at 17:41 Moscow Time, carrying the Pirs Docking Compartment, SO1, with it. The docking of the MLM Nauka module at the nadir port of the Zvezda Service Module, SM, was scheduled on July 23, 2021, at 19:28 Moscow Time.

Following the successful VKD-48 spacewalk on June 2, 2021, two more spacewalks were planned in September 2021, to configure Nauka for docking with transport ships. The first docking with the module would be tested on Sept. 25, 2021, by moving the Soyuz MS-18 spacecraft from the MIM1 Rassvet module to the Nauka's nadir port (Insider Content).

The crew vehicle would remain there until the departure of Expedition 65 on Oct. 17, 2021. Then, the Progress MS-17 cargo ship would be re-docked to Nauka's nadir port and remain there until the launch of the Prichal node module, UM, on Nov. 24, 2021.

After discarding Prichal's instrument compartment in the second half of December 2021, three more spacewalks — VKD-51, 52 and 53 — could proceed in January 2022 to integrate Prichal and to continue the configuration of Nauka for routine functioning as part of the Russian Segment.

Roskosmos announces new timeline for Nauka launch


Payload section with the MLM module is being transported on the inter-hall trailer at Site 254 on July 5, 2021.

The missing thermal insulation discovered on the Nauka module around July 1 (Insider Content), forced to postpone the mission from July 15 to July 21, 2021, at 17:58:21 Moscow Time. The backup launch opportunities were also available on July 22 and 23, Roskosmos announced on July 8.

On the condition of the successful launch of Nauka on July 21, the undocking of the Progress MS-16 cargo ship with the Pirs Docking Compartment, SO1, from the Zvezda Service Module, SM, was scheduled for July 23, 2021, to free the nadir (Earth-facing) port on the Zvezda for the new module. According to initial information from Roskosmos quoted by NASA, the undocking was scheduled to take place at 16:17 Moscow Time, but by the time of Nauka's launch on July 21, the undocking time was updated to 16:25 Moscow Time. Around four hours after its departure from the station, the Progress/SO1 stack would be deorbited over the remote area of the Pacific Ocean.

If launched on July 21, the Nauka was preliminary scheduled to dock at the Russian Segment of the ISS on July 29, 2021, at 16:26 Moscow Time, the July 8 announcement said.


Spacewalks for integration of the MLM Nauka and UM Prichal modules with the Russian ISS Segment:

Key task
Preparing SO1 Pirs for undocking
2021 June 2
Cleaning nadir port on Zvezda after SO1 Pirs departure (conti)
2021 July (contingency)
Connecting cables between US Segment and Nauka
2021 Sept. 3
Connecting cables between Zvezda and Nauka
2021 Sept. 9
Configuring the Prichal Node Module, UM
2022 Jan. 19
ERA robotic arm initiation
2022 April 18
ERA move to parking position
2022 April 28
ERA lens cover replacement
2022 July 21
ERA cameras (CLUs) installation, launch bracket removal
2022 Aug. 17
Finishing tasks of aborted VKD-54
2022 Sept. 2
Nitrogen drainage from the RTOd radiator (IC)
2022 Nov. 17
RTOd radiator transfer
2023 April 19
Science airlock, ShK, (IC) transfer
2023 May 3
ERA tethers installation
2023 May 12
Equipment replacement, Zvezda SM inspection
2023 June 22
PRM transfer from MIM1 to MLM, MIM1 MMZ installation
2023 Aug. 9
Rakurs radar installation, RTOd leak isolation
2023 October (planned)
2023 December (planned)




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Text, photos and illustrations by Anatoly Zak unless stated otherwise; Last update: October 25, 2023

Page Editor: Alain Chabot; Last edit: October 24, 2017

All rights reserved

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An isolated view of the Russian Segment after the addition of the MLM module. Credit: Roskosmos


Nauka is being prepared for testing in vacuum chamber on April 16, 2021. Click to enlarge. Credit: Roskosmos


Russian cosmonauts Sergei Korsakov and Dmitry Petelin performed spacewalk training at Star City on June 1, 2021. Click to enlarge. Credit: Roskosmos


Petr Dubrov rides Strela boom during the VKD-48 spacewalk on the ISS in preparation for the departure of the Pirs Docking Compartment, SO1, on June 2, 2021, as seen by NASA astronaut Mark Vande Hei from inside the station. Click to enlarge. Credit: NASA