Leonard David's INSIDE OUTER SPACE

Image credit: NASA

On June 5, while pressurizing the Zvezda module’s transfer chamber (Tcha) to International Space Station (ISS) pressure, specialists from the ISS Russian Segment’s lead operations team detected a leak in the Tcha.

During an inspection of the Tcha, the cosmonauts discovered two potential air leaks. The first was quickly sealed with the first layer of Germetal-1, a two-component sealant. The second leak is located on the conical portion of the Tcha. Preparations are underway to seal it.

Stable situation

In an official comment from Russia’s Roscosmos State Corporation, the situation on the ISS has been detailed relating to the detection of leaks in the hardware’s transfer chamber.

“The situation does not pose a threat to the safety of the crew or onboard systems; the pressure on board the ISS is stable and maintained at the calculated level,” explains Roscosmos.

“NASA astronauts, who were transferred to the docked Crew Dragon spacecraft during repairs to the transfer chamber, have returned to the ISS to resume normal operations.”

Image credit: NASA

Root cause

The Zvezda Service Module was the first fully Russian contribution to the ISS. The module provides station living quarters, life support systems, electrical power distribution, data processing systems, flight control systems and propulsion systems. It provides a communications system that includes remote command capabilities from ground flight controllers, and a docking port for Russian Soyuz and Progress spacecraft.

The Zvezda service module’s transfer tunnel has experienced cracks since 2019 that have resulted in small atmosphere leaks and prompted ongoing monitoring and repair efforts by Roscosmos.

NASA and Roscosmos have worked together to identify the root cause while Roscosmos has been applying leak mitigation measures, including temporary and permanent sealants.