Russian Space Station Module Springs a Coolant Leak

Russia’s newest International Space Station module, Nauka, began leaking coolant from a radiator today. This is third Russian radiator to spring a leak in less than a year. The Nauka radiator actually has been in space for over a decade waiting for Nauka to arrive so whether there is any commonality to the failures is difficult to assess. Roscosmos acknowledged the leak, but said the module itself is working fine and there is no cause for concern.

Reports of the leak came first from U.S. space reporters monitoring communications between NASA’s Mission Control in Houston and astronauts aboard the ISS.

In early afternoon, CBS News’ Bill Harwood, based at Kennedy Space Center, posted on X (formerly Twitter) that Mission Control asked the ISS crew to look out the windows in the cupola to see if there were signs of flakes. NASA astronaut Jasmin Moghbeli replied yes.

ISS: In the last few minutes, MCC-Houston asked the ISS crew to go to the cupola and look for any signs of “flakes” toward the aft of station; Jasmin Moghbeli reported “yeah, there’s a leak coming from the radiator on MLM;” the MLM is the Russian Nauka multi-purpose lab module

— William Harwood (@cbs_spacenews) October 9, 2023

Spaceflight Now then reported that NASA directed the astronauts to close the shutters over the windows to protect them from contamination.

A leak from a radiator on the Russian Nauka laboratory module has been confirmed by the space station crew. NASA mission control has asked for the station’s window shutters to be closed. You can listen to live audio in our Launch Pad Live Stream: https://t.co/FVz8ZF6Z63

— Spaceflight Now (@SpaceflightNow) October 9, 2023

In a post on the social media platform Telegram, Roscosmos confirmed the leak, but downplayed its significance. As translated by Google, the agency said it is a backup circuit and the main thermal control loop is fine.

On the Science module of the Russian segment of the ISS, a coolant leak occurred from the external (backup) radiator circuit, which was delivered to the station in 2012.

The main thermal control circuit of the module operates normally and provides comfortable conditions in the living area of the module.

The crew and the station are not in danger.

The work of the main operational management group continues to analyze the current situation.

t.me/roscosmos_gk/11130  26.2K views edited Oct 9 at 14:49  — Roscosmos

Nauka (Science), also known as the Multipurpose Laboratory Module (MLM), was finally launched in 2021 after years and years of delay. Anatoly Zak of RussianSpaceWeb.com traces the tortuous history of the 20.2 Metric Ton module, the largest built by Russia since the Zarya and Zvezda modules launched at the beginning of ISS assembly in 1998 and 2000.

Nauka was supposed to be launched a decade earlier and some of the equipment to be placed on the module’s exterior was sent to ISS in advance. Roscosmos said the radiator that leaked today has been at ISS since 2012, but a radiator for Nauka was delivered in 2010 on a U.S. space shuttle flight (STS-132) as part of Russia’s Mini Research Module-1, also known as Rassvet.

Zak’s illustration of Nauka as it was designed in 2016 shows both a radiator panel and body-mounted radiators. He told SpacePolicyOnline.com today it’s not clear at this moment where the leak is.

All that is known is “Roskosmos’ claim that it is ‘external (backup)’ which is too general. Yes, the RTOd panel and its interface has been in space since 2010 on Rassvet, but it now connects to a supply system which came with Nauka,” Zak told us.

Nauka’s docking with the ISS on July 29, 2021 did not go as planned when its engines suddenly sprang back to life and changed the space station’s orientation, but it since has settled in as a standard component of the 420 MT facility.

Today’s leak was Russia’s third since December 2022 when the Soyuz MS-22 spacecraft lost its coolant just as two Russian cosmonauts were about to exit a nearby hatch to conduct a spacewalk.

Soyuz transports crews to and from ISS. Roscosmos determined Soyuz MS-22 was not safe to bring its three crewmembers home — Russian cosmonauts Sergey Prokopyev and Dmitri Petelin and NASA astronaut Frank Rubio. The trio ended up staying on ISS for 371 days instead of six months as the crew rotation schedule was revised so the Soyuz MS-23 spacecraft could be launched empty to serve as their ride home. They landed last week after their replacements, now on Soyuz MS-24, arrived.

Soyuz spacecraft have three compartments, one of which houses the crew and is designed to survive reentry. The other two burn up in the atmosphere, including the portion where the leak occurred so it may never be known what caused the leak.

Roscosmos concluded the most likely culprit was impact from a micrometeoroid or space debris, but in February 2023, Progress MS-21 also lost its coolant. Progress and Soyuz are very similar in design, but Progress is for cargo and Soyuz for crew. Roscosmos said that also was likely due to an “external impact.” No part of Progress survives reentry so it is not possible to study what happened.

In a post on the ISS blog late today, NASA said “Teams on the ground will continue to investigate the cause of the leak” and reiterated that the “primary radiator on Nauka is working normally, providing full cooling to the module with no impacts to the crew or to space station operations.”