US space officials do not like to talk about the perils of flying astronauts on the aging International Space Station, elements of which are now more than a quarter of a century old.
However, a new report confirms that NASA managers responsible for operating the space station are seriously concerned about a small Russian part of the station, essentially a tunnel that connects a larger module to a docking port, which is leaking.
Russian and US officials have known that this small PrK module, which lies between a Progress spacecraft airlock and the Zvezda module, has been leaking since September 2019. A new report, published Thursday by NASA’s inspector general, provides details not previously released by the space agency that underline the severity of the problem.
New details about the leak
For example, in February of this year NASA identified an increase in the leak rate from less than 1 pound of atmosphere a day to 2.4 pounds a day, and in April this rate increased to 3.7 pounds a day. Despite years of investigation, neither Russian nor US officials have identified the underlying cause of the leak.
“Although the root cause of the leak remains unknown, both agencies have narrowed their focus to internal and external welds,” the report, signed by Deputy Inspector General George A. Scott, states.
The plan to mitigate the risk is to keep the hatch on the Zvezda module leading to the PrK tunnel closed. Eventually, if the leak worsens further, this hatch might need to be closed permanently, reducing the number of Russian docking ports on the space station from four to three.
Publicly, NASA has sought to minimize concerns about the cracking issue because it remains, to date, confined to the PrK tunnel and has not spread to other parts of the station. Nevertheless, Ars reported in June that the cracking issue has reached the highest level of concern on the space agency’s 5×5 “risk matrix” to classify the likelihood and consequence of risks to spaceflight activities. The Russian leaks are now classified as a “5” both in terms of high likelihood and high consequence.
