What happens if Russia decides to seal off the damaged Zvezda module on the International Space Station (ISS)? It's a critical question that has emerged from a recent tense situation aboard the ISS. NASA's astronauts were instructed to secure themselves in the Dragon capsule, preparing for a potential return to Earth, while their Russian counterparts performed impromptu demolition work on the Zvezda module, a core component of the ISS. This module, in orbit since 2000, has been experiencing persistent leaks that have been venting the station's atmosphere into space for years.
The Zvezda module houses the Transfer Chamber, known as the PrK, which is a small vestibule connecting the module's interior to the rear docking port. Cracks in the PrK's walls have allowed air to leak into an unpressurized equipment bay, despite the external hull remaining intact. The immediate solution is to close the hatch leading into the PrK, which means abandoning the docking port on the other side.
This isn't an ideal situation, but it's a compromise that has become more common as the ISS ages. The Russian section of the station has multiple docking ports, and while losing one is a challenge, it's manageable. The PrK can still be used for resupply activities, as the plumbing for water, oxygen, and propellants is run on the outside and linked through connectors in the docking port.
However, the real concern is reboost maneuvers. Progress spacecraft docked to the rear of the Zvezda module typically use their thrusters to change the velocity of the entire complex, counteracting atmospheric drag. This maneuver is crucial for maintaining the station's orbit. If NASA and Roscosmos determine that continuing these maneuvers from the Zvezda module is unsafe, they may need to switch to the US side, which has been done before with the Space Shuttle and a modified Cargo Dragon.
This situation isn't new. Since 2024, the official procedure has been to keep the PrK hatch closed unless actively loading or unloading a docked vehicle. This reduced air leakage but introduced a risk of catastrophic failure. If the rumors are true and Russia decides to seal off the Zvezda module, it's a temporary fix for an aging station, ensuring the peace with NASA until the ISS's final years.
