ISS Leak Standoff Exposes Aging Hardware and Repair Risks
Not only did a brief shelter order on the International Space Station on June 5 interrupt work in space, but it also highlighted the challenging nature of any old spacecraft aging structure, repair options, and coordination between operators can make the situation go from localized to much bigger.
In particular, it became known that a part of the PrK transfer tunnel, connecting the Russian service module Zvezda with the station’s aft docking port, was experiencing leaks since 2019. As NASA reported, Roscosmos has noticed an increased leak rate during cargo operations a week prior to the order and decided on further measurements and repair of the new leak spots.
NASA press secretary Bethany Stevens said that five astronauts took shelter in a docked Dragon spacecraft “out of an abundance of caution” due to the Russian “mitigation measures” aimed at repairing “cracks.” Later, NASA said that after Roscosmos suspended the work on the structural repairs and started measurements and data analysis, the crew returned to station’s normal operations.
What’s the point of such detailed timeline? The problem was not just an air leak. The suggested repair plan included a cut of a bracket to get to the leaking area. According to NASA, the chosen procedure could add structural risks to the already damaged part. In other words, the first question here was not only how to fix the leaking spot, but whether it is better to avoid increasing structural risks in that area.
This is the general public’s main take-away from this case. Maintenance of spacecraft is usually limited by access, materials, and the simple fact that space equipment cannot be taken apart easily like it can be done on Earth. A tunnel with recurring leaks is an engineering challenge. A tunnel which additionally serves as a docking area is another challenge as the pressure, access, and structural work decisions can impact the whole station and not only the tunnel itself.
The importance of PrK is connected with the fact that the tunnel leads to the docking port used by Progress cargo spacecrafts. Even in case of the PrK isolation or unpressurization, the station will remain operable, but the range of options will be limited. ESA astronaut Andreas Mogensen said last year that in case of the most unfavorable situation, the module could be sealed off and the station would remain operable, but there were other potential challenges. This is a good practical description of what will happen in that situation: it is still possible to operate, but with reduced margins and options.
But this is also an American-relevant issue even though the hardware in question belongs to the Russian segment of the station. Space station operations require great interdependence. NASA ordered four Crew-12 crew members and NASA astronaut Chris Williams to shelter in the Dragon spacecraft because of the proposed repair activity. Thus, a maintenance decision in one part of the station impacted directly the crew configuration, emergency readiness, and utilization of the American spacecraft in another part of it.
And finally, there is a management-related aspect of the case. For years NASA and Roscosmos have cooperated in order to find the source of the leaks and use temporary and permanent seals. But June 5 showed that even in case of the shared problem, a quick change of mind can occur if one party feels uncomfortable with the solution.
But some information about the more aggressive repair approaches was published anonymously. The facts confirmed by both sides include the leak area being problematic since 2019, increased leak rate, the preparation of the extended structural repair by Roscosmos, the assessment of NASA that the suggested way of repair is dangerous enough to send astronauts to shelter, and the suspension of the work in favor of the measurements by Roscosmos.
Also, there are rumors about PrK section being decommissioned and unpressurized, thus limiting the use of the dock connected to it. In this case, it will be the classic decision for a long-life space station: retire the problematic hardware to lower the structural risks and accept the consequences of this action.
As for the station which provided support to astronauts during more than twenty years, the main conclusion should be drawn. The longevity of spacecraft in space is not only about the maintenance of old hardware, but the understanding of the time when the repair itself can become a risk. And it is about isolation of a problem and preservation of crew safety and mission continuity in such conditions.
By David Whitaker — Associate editor for AMI’s aerospace and drone systems desk, translating flight systems, aircraft programs, spaceflight, and UAV developments into accessible technical stories.
