NASA inspector general: Air leak in Zvezda module on ISS increased significantly in 2024
Figure 3 from IG report, annotated by me to show Zvezda location.
According to a new report [pdf] from NASA’s inspector general, the air leaks in the Russian Zvezda module on ISS increased significantly in 2024, reaching “the highest level of risk in its risk management system,” and more than six times the normal planned leak rate for the station (see the box in the lower corner of the figure above).
[I]n February 2024 NASA identified an increase in the leak rate, and the Agency and Roscosmos continue to assess the risk that the increase poses to the module’s structure. In May and June 2024, ISS Program and Roscosmos officials met to discuss heightened concerns with the increased leak rate. The ISS Program subsequently elevated the Service Module [Zvezda] Transfer Tunnel leak risk to the highest level of risk in its risk management system. According to NASA, Roscosmos is confident they will be able to monitor and close the hatch to the Service Module prior to the leak rate reaching an untenable level. However, NASA and Roscosmos have not reached an agreement on the point at which the leak rate is untenable.
To mitigate potential impacts from the air leaks, NASA and Roscosmos continuously monitor leak rates and close the hatch to the Service Module when access is not required, sealing the module to minimize air loss while isolating the leak. While it is possible for the ISS to function if the hatch is closed permanently, it could impact cargo delivery because there would be one less cargo delivery port. Closing the hatch permanently would also necessitate additional propellent to maintain the Station’s altitude and attitude. Although the root cause of the leak remains unknown, both agencies have narrowed their focus to internal and external welds. As of June 2024, there was no indication of other leaks on the Station.
The transfer tunnel is the section of Zvezda that connects it to ISS. Though the report is very careful not to say anything specific about the cause of the leak, the evidence strongly suggests it is caused by stress fractures in the module’s hull, fractures that indicate a serious and dangerous long term issue. The tunnel however cannot be replaced without replacing Zvezda, and Zvezda cannot be replaced without detaching the entire Russian section from ISS, something that is likely very difficult and maybe impossible to do. And even if it could be replaced, Russia does not have the capability or the money right now to build a replacement.
The report also noted that keeping the station operating through 2030 faces other challenges, including the lack of redundancy for getting cargo and crew to ISS, the increasing difficulty of obtaining spare parts for the station, the long term damage from micrometeoroids and orbital debris, and finally, the unknown commitment of Russia, which at this point has not yet decided whether it will remain a partner after 2028.
All these issues underline the need for the four American private commercial space stations to reach orbit and get operational before 2028.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
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Figure 3 from IG report, annotated by me to show Zvezda location.
According to a new report [pdf] from NASA’s inspector general, the air leaks in the Russian Zvezda module on ISS increased significantly in 2024, reaching “the highest level of risk in its risk management system,” and more than six times the normal planned leak rate for the station (see the box in the lower corner of the figure above).
[I]n February 2024 NASA identified an increase in the leak rate, and the Agency and Roscosmos continue to assess the risk that the increase poses to the module’s structure. In May and June 2024, ISS Program and Roscosmos officials met to discuss heightened concerns with the increased leak rate. The ISS Program subsequently elevated the Service Module [Zvezda] Transfer Tunnel leak risk to the highest level of risk in its risk management system. According to NASA, Roscosmos is confident they will be able to monitor and close the hatch to the Service Module prior to the leak rate reaching an untenable level. However, NASA and Roscosmos have not reached an agreement on the point at which the leak rate is untenable.
To mitigate potential impacts from the air leaks, NASA and Roscosmos continuously monitor leak rates and close the hatch to the Service Module when access is not required, sealing the module to minimize air loss while isolating the leak. While it is possible for the ISS to function if the hatch is closed permanently, it could impact cargo delivery because there would be one less cargo delivery port. Closing the hatch permanently would also necessitate additional propellent to maintain the Station’s altitude and attitude. Although the root cause of the leak remains unknown, both agencies have narrowed their focus to internal and external welds. As of June 2024, there was no indication of other leaks on the Station.
The transfer tunnel is the section of Zvezda that connects it to ISS. Though the report is very careful not to say anything specific about the cause of the leak, the evidence strongly suggests it is caused by stress fractures in the module’s hull, fractures that indicate a serious and dangerous long term issue. The tunnel however cannot be replaced without replacing Zvezda, and Zvezda cannot be replaced without detaching the entire Russian section from ISS, something that is likely very difficult and maybe impossible to do. And even if it could be replaced, Russia does not have the capability or the money right now to build a replacement.
The report also noted that keeping the station operating through 2030 faces other challenges, including the lack of redundancy for getting cargo and crew to ISS, the increasing difficulty of obtaining spare parts for the station, the long term damage from micrometeoroids and orbital debris, and finally, the unknown commitment of Russia, which at this point has not yet decided whether it will remain a partner after 2028.
All these issues underline the need for the four American private commercial space stations to reach orbit and get operational before 2028.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
2nd to the last paragraph: “space” parts (though I like it!) should probably be “spare” parts.
Michael McNeil: Thank you. Fixed, along with several other typos I myself noticed a few minutes earlier.
Perhaps I’m just old-fashioned, but it seems to me that a report noting a worrisome rise in leak rate from the ISS should have some actual numbers quantifying both past and present leak rates. I couldn’t find any such in the linked PDF. It’s probably on a par with a small child wishing for a pony but it would have been nice if NASA had gone nuts entirely and put such data in the form of a graph. Apparently, that’s too big an ask.
Dick Eagleson: I reference in my post the chart in the lower right of the figure at the top of the post, taken from the IG report. It provides specific numbers.
Obviously, they make those numbers hard to find in order to minimize the issue. This is the government you know.
I wish we could just cut it off and use Zarya, but the engines on that have been disabled and the docking of the other Russian modules are on Zvezda’s ports.
We have talked about this a number of times on this board: well over one hundred dockings have taken place on the aft port of the Zvezda module. There are other leaks as well and not just at the aft. It was around February this year, or late last year, that the Russians claimed they fixed the leaks on the aft port and it looks like those failed or there are new leaks.
“All these issues underline the need for the four American private commercial space stations to reach orbit and get operational before 2028.”
See my comments on the above post re the need to make the intransigence of the FAA a campaign issue. The success of American commercial space stations is also an existential one! Tell the FAA to concentrate on fixing Boeing and get out of the way of the others!
A private company should just make a cheap replacement for that module and come up with a way to replace it.
They could use a second girder attached to the primary girder and use it as an expansion joint or connection.
This would keep the rest of the station stable and in alignment.
ZimmerBob,
Thanks for pointing out what should have been obvious. My mental “dog” was apparently off chasing the “squirrel” of that illustration and missed the far less flashy text box.
Those numbers are worrisome, especially the recent rate trendline. I think it’s now more than fair to posit that there is a real horserace going on between the notional date for dropping ISS into Point Nemo and part or all of the Russian side simply breaking off and drifting away before that can happen.
I also think we need to be making contingency plans for what to do in case that Russian side break-off happens during the ISS de-orbit burn. In that case, neither piece of ISS will likely come down where currently planned and we could be looking at one entirely uncontrolled re-entry and a second that may only be under partial control at best.
It’s cute that NASA reports in pounds.
It appears (to the Intertubes) that cheap-to-orbit is around $4,000/pound; expensive is around $10,000. 4 pounds per day is a rather expensive leak.
Actually those two Soviet Modules are not essential to the station and can be kicked off with little problem.
Whatever they do can be replaced quickly by a single private module.
You place a 6 sided docking module and an inflatable living/working module to replace it. Boom bigger cheaper and faster.
Russia can take their modules and dock to the Chinese station with all our best wishes.
”The transfer tunnel is the section of Zvezda that connects it to ISS.”
From the context in the excerpt you posted, I don’t think that’s true. If it were, closing its hatches would cutoff both the Soyuz and the Russian science lab from the rest of the station, particularly the crew quarters on the RSOS. I thinks it’s referring to the aft hatch, which would ordinarily lead to a Progress cargo module.
”A private company should just make a cheap replacement for that module and come up with a way to replace it.”
I’m sure the Russian government will get right on that. Right after they allow private space companies to exist.
”Actually those two Soviet Modules are not essential to the station and can be kicked off with little problem.”
On the contrary, the Zvezda module is the most important module on the station. It is the only one with a propulsion system and the only one that can do orbital reboost and propulsive attitude control. Without it the whole ISS goes into an uncontrollable spin within a few weeks and falls out of orbit within two years.