Russia is poised to halt major repairs on the leaking PrK transfer tunnel of the International Space Station (ISS) and keep the hatch sealed, a move that would cut air loss but also restrict how astronauts can use the station. This development comes as NASA faces a 2027 deadline to decide if commercial stations can replace the ISS before its planned 2030 retirement—a decision that could reshape funding and timelines for private space station projects.
Current Situation and Repair Plans
On June 5, NASA placed five astronauts into a SpaceX Dragon capsule as Roscosmos prepared to cut a bracket near suspected leak spots. After the operation, the crew resumed normal operations. The leak, which has worsened recently, now causes air loss of about two pounds per day when the Progress 95 cargo ship is docked. Roscosmos has identified new potential leak sites ahead of a deeper inspection.
Instead of dismantling aging equipment, NASA and Roscosmos may simply close the door on the PrK—a small transfer tunnel in Russia's Zvezda service module that connects to an aft docking port. Reports this week indicate the PrK could be decommissioned or left unpressurized. NASA grew concerned after the repair plan on June 5, leading to the U.S. crew moving to a return capsule as a precaution.
NASA's Concerns and Responses
NASA warned that Russia's plan to cut a bracket near the suspected leak source "could have resulted in elevated risk" to other station components. In response, NASA ordered the four SpaceX Crew-12 astronauts and NASA's Chris Williams into the Dragon capsule as a "safe haven," ready to return to Earth if needed. NASA press secretary Bethany Stevens described the step as "out of an abundance of caution." After Roscosmos halted the repair to take new measurements, Stevens emphasized the need for a "collaborative approach."
Roscosmos provided a different account, stating that two leaks exist—one already sealed with a hermetic compound—and work continues on the second. The agency also noted that ISS pressure remains stable, with no immediate danger to the crew or systems.
Broader Implications for Station Operations
The tension extends beyond a single patch. A Progress cargo ship docked at Zvezda's rear port is typically used for reboosts—engine burns that maintain the station's orbit. Sealing the PrK hatch might still allow some fluid transfers, but it would complicate access to cargo and raise questions about load limits. ESA astronaut Andreas Mogensen told The Register last year that if the cracks are isolated to the end chamber, Russia could give up that docking area with limited impact on ISS functions. "You could seal it off," he said, but warned of potential new issues.
Commercial Push and Market Implications
The commercial space station push is intensifying. NASA is in talks with firms like Axiom Space, Blue Origin's Orbital Reef, and Starlab to build private successors to the ISS. However, the U.S. Government Accountability Office (GAO) said NASA has not yet locked in its acquisition plan for the handoff. Clayton Swope, a space analyst at the Center for Strategic and International Studies (CSIS), noted in May that the commercial station business remains almost entirely dependent on NASA demand, calling the agency "nearly the whole market." If the ISS is extended or suffers a sudden loss of capability, it could determine which private stations survive the pause and secure funding.
Technical and Operational Risks
Closing the PrK is not a permanent fix. While air loss may decrease, it remains unclear whether new cracks will appear in Zvezda's aging structure. Options for docking and station-keeping become more constrained as the ISS nears its end. Neither NASA nor Roscosmos has confirmed a permanent shutdown of the PrK. The station remains operational, but the dispute highlights the larger challenge: the ISS must continue until a replacement arrives, and that goal is looking increasingly uncertain.
