NASA is increasingly concerned about leaks in the ISS’s Russian segment tunnel, with the root cause still unknown. The leaks have worsened, releasing 3.7 pounds of atmosphere daily by April. NASA and Roscosmos are investigating, focusing on internal and external welds. Supply chain issues complicate repairs. In June, NASA elevated the issue to its highest concern level. If unresolved, the hatch may be permanently closed, limiting docking ports. NASA and Roscosmos have yet to agree on an untenable leak rate, complicating ISS operations before its planned 2030 deorbit.