Tag: Zvezda

NASA reveals that it and Russia disagree about the danger posed by the airleak on ISS

8:54 am

Figure 3 from IG report
Figure 3 from September Inspector General report, annotated by me to show Zvezda location.

In a public session yesterday by a NASA commission focused on accessing the safety condition of ISS, officials revealed that the commission and Russia disagree about the root causes behind the airleak and cracks in the docking section of the Zvezda module on the Russian half of ISS, as well as the risk of a catastrophic failure. According to the commission’s head, former astronaut Bob Cabana.

The Russian position is that the most probable cause of the PrK cracks is high cyclic fatigue caused by micro vibrations. NASA believes the PrK cracks are likely multi-causal including pressure and mechanical stress, residual stress, material properties and environmental exposures.

The Russians believe that continued operations are safe, but they can’t prove that to our satisfaction. The U.S. believes that it’s not safe, but we can’t prove that to Russian satisfaction that that’s the case. So while the Russian team continues to search for and seal the leaks, it does not believe catastrophic disintegration of the PrK is realistic and NASA has expressed concerns about structural integrity of the PrK and the possibility of a catastrophic failure.

Because of this disagreement American astronauts now close the hatch between the Russian and American halves of ISS whenever a docking to Zvezda is taking place, and apparently keep that hatch closed until unloading of the docked spacecraft is complete. The Russians in turn only open the hatch to the docking section of Zvezda when they need to load or unload material into the freighter docked there, and coordinate with American astronauts whenever they do so.

Engineers from the two nations continue to discuss the issue, and hope to result their disagreement and come up with a joint plan.

Ultimately, this issue indicates the certain end of ISS in the near future, and adds ugency to the need to get some of those commercial space stations operating in orbit.

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NASA inspector general: Air leak in Zvezda module on ISS increased significantly in 2024

12:14 pm

Figure 3 from IG report
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.

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Air leak in Russia’s half of ISS continues and has increased slightly

9:34 am

Zvezda module of ISS
The Zvezda module, with aft section indicated
where the cracks have been found.

The leak in the Russia half of ISS continues to bleed air from the space station and has even increased slightly in recent months, though both NASA and Roscosmos say the rate of loss is tiny and poses no danger to the station’s inhabitants.

“There is no threat to the crew or the station itself,” [Roscosmos] said in a statement carried by Russian news agencies. Roscosmos’ statement followed comments by Joel Montalbano, NASA’s station project manager, who noted Wednesday that the leak in the Russian segment has increased but emphasized that it remains small and poses no threat to the crew’s safety or vehicle operations.

As indicated by the graphic to the right, the air loss is suspected to come from stress fractures in the Zvezda module, the station’s second oldest and one in which many dockings have occurred over the past two decades. Russia had suspended dockings in this port shortly after the leaks and cracks were detected, but have apparently resumed those dockings recently. One wonders if this new activity is contributing to the increase in loss of air.

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NASA and Russian engineers meeting to discuss status of leaks on ISS’s Zvezda module

9:40 am

According to Russia’s state-run press, NASA and Russian engineers have been reviewing the status of the repairs on the cracks in the Zvezda module on ISS.

Repairs to the various cracks in Zvezda’s hull, done by Russian astronauts in ’20 and ’21, have reduced the leakage from 1,140 grams per day to 300 grams per day. Normally ISS is expected to lose 325 grams per day, across the entire station, so the Zvezda leak doubled this loss, even after the repair. Thus, the hatch to Zvezda is kept closed in order to maintain the atmosphere of ISS at its normal levels, and opened only when there is need to enter it. In addition, its port is no longer used for dockings.

The engineering review is also looking into the cause of the cracks, which are believed to be stress fractures caused by the age of Zvezda (ISS’s second oldest module) combined with the many dockings that had occurred at its port. The review is also discussing ways to reduce the problem, until ISS’s retirement in 2030.

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Russian astronauts locate another leak on Zvezda

8:44 am

According to Russia’s state-run TASS press, Russian astronauts have located what it calls “the last air leak” on the Zvezda module of ISS.

Russian cosmonauts Anton Shkaplerov and Pyotr Dubrov discovered the last air leak location in the International Space Station’s Zvezda module, Roscosmos spokesman Dmitry Strugovets said Tuesday, adding that the leak will be eliminated after special equipment is delivered to the station.

Like most of the other leaks previously found, this one was located in the aft transition chamber where the Zvezda docking port is located, once again suggesting that these leaks are the result of stress fractures caused by age and the more than a hundred dockings that have occurred there since Zvezda was launched more than twenty years ago.

The Russians’ belief that no more leaks will be found is probably based on their decision to reduce, even cease the use of this port. The new Prichal docking hub, which two Russians today are doing a spacewalk to finalize its integration with the station, makes the shuttering of Zvezda’s port possible.

At the same time, the existence of numerous stress fractures in an ISS module is not something to be dismissed lightly, as the TASS article attempts to do. It is akin to cracks in the hull of a submarine, and I don’t know anyone who would be willing to send such a vessel deep underwater.

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Biden administration commits to operating ISS through 2030

5:46 pm

The Biden administration yesterday announced that it has committed NASA to operating the International Space Station (ISS) through 2030, a six year extension to the previous end date of 2024.

Today’s abrupt announcement on a federal holiday comes one day after Biden and Putin had a “serious and substantive” telephone conversation about the situation in Ukraine where Russian troops are massed at the border. Biden has said that if Russia invades Ukraine the United States and its allies will respond with more economic sanctions. A Russian official told reporters later that Putin warned Biden that any such sanctions “could result in a ‘complete rupture’ of relations” between the two countries, according to the New York Times.

…Asked why the ISS extension was announced today and if it is related to the Biden-Putin call, a NASA spokesperson told SpacePolicyOnline.com only that it has “been in the works for months.”

A White House commitment to 2030 falls short of setting the date in law, but demonstrates U.S. intentions at least as long as Biden is President. Whether the other partners, especially Russia, agree will be interesting to watch. ESA’s Director General, Josef Aschbacher, welcomed the news, but it will be the 11 ESA members who participate in the program who make the decision.

The article gives a good overview of the political issues, and notes accurately that it will be very difficult to operate the station if Russia and the U.S. part ways and Russia leaves the partnership.

What the article did not mention is the fragile state of some of Russia’s modules. Both Roscosmos and NASA know that the Zvezda module, the second oldest on ISS, is showing very worrisome signs of aging, including many stress fractures that have caused small airleaks. The Russians themselves have admitted that the module is failing, and have added that because of this fact the Putin government has begun work on a new and independent Russian station.

It is unclear if ISS could function if Zvezda became unusable. At a minimum its capabilities will be reduced. At worst it might not be safe to occupy.

The Biden administration and NASA can extend ISS on paper as much as they want, but reality suggests that it will be a dangerous challenge to keep the station running until 2030. The real solution is to get as many private commercial American stations launched in the next few years, so that when Zvezda fails, there will be viable options to ISS.

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Russian astronaut id’s possible leak location in Zvezda

9:50 am

A Russian astronaut today told mission control that he thinks he has located another leak in the Zvezda module of ISS.

Roscosmos cosmonaut Pyotr Dubrov detected a possible air leak spot in the intermediate chamber of the Zvezda module aboard the International Space Station (ISS), the cosmonaut told the Flight Control Center during a communications session on Monday.

The Russian cosmonaut said he had traced the possible spot of the continued air leak while inspecting the Zvezda module’s intermediate chamber at the weekend. “I began preparing a perimeter for laying a cord today. I detected a suspicious spot and started to examine it,” the cosmonaut said, replying to a question about the work in the intermediate compartment in a live broadcast by NASA.

As the Russian cosmonaut said, he made a photo of the detected spot using a microscope with magnifying lens. He did not make video footage of the works, he said. [emphasis mine]

The highlighted words are significant. Up until now all leaks that the Russians have identified have been in Zvezda’s aft section, the part where the docking port is located. That pattern suggested that the many dockings over the module’s two decade-plus lifespan could have led to stress fractures in that module.

That they might have now found an air leak in intermediate section of the module suggests that the age-caused stress fractures are occurring in a more widespread manner. This is very concerning.

On a positive note, when the astronauts sealed the earlier leaks in the aft module, the loss of air dropped significantly. If the leak stops entirely when they seal this leak, we will have some confidence that the problem is under some control, for the time being.

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Russia launches Progress freighter to ISS

9:54 pm

Using its Soyuz-2 rocket, Russia today successfully launched a Progress freighter to ISS, carrying more than 5,000 pounds of cargo.

The freighter is scheduled to dock with ISS Friday evening at 9:34 pm (Eastern). It will dock with the port on the 20-year-old Zvezda module, which has remained unused for the past six months because of concerns that the docking and undocking at the port was causing stress fractures in the sections of Zvezda closest to the port. The Russians have decided to do this docking for the express purpose of studying its impact on the module.

The Progress MS-18 spacecraft will link up with the rear docking port on Zvezda. With the help of cosmonauts on the station, Russian engineers have traced a small air leak on the station to the transfer compartment leading to Zvezda’s rear port. The compartment has been sealed from the rest of the space station since the departure of a previous Progress spacecraft from the rear docking port in April. But cosmonauts will re-open the compartment to unload cargo delivered by the Progress MS-18 spacecraft.

The leaders in the 2021 launch race:

38 China
23 SpaceX
18 Russia
4 Northrop Grumman
4 ULA
4 Arianespace (Europe)

China remains ahead of the U.S. 38 to 36 in the national rankings.

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Russian engineers to dock next Progress to Zvezda to test it

8:25 am

Russian engineers have decided that they will dock the next Progress freighter flying to ISS and scheduled to launch tomorrow to the Zvezda module in order to find out if the stress of that docking will cause more cracks in the module’s aft section.

Scheduled for launch in early hours of October 28, 2021, the Progress MS-18 cargo ship will be on a two-day trip to the International Space Station, aiming to dock at the aft port of the Zvezda Service Module, ISS. That particular docking mechanism was unoccupied for half a year, because it is connected to the rest of the outpost via the PrK transfer compartment, which had been leaking air despite all efforts to seal tiny cracks in its walls. Progress MS-18 should confirm that the PrK chamber could be used safely.

This is not crazy, it actually makes a great deal of sense. The engineers need to know if a docking results in more cracks. If so, it will confirm the cause and also provide them the data they need to prevent such things on future manned space vessels.

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Due to cracks, Russia will no longer use Zvezda’s docking port

9:39 am

Russian officials today revealed that they will no longer use the docking port on its Zvezda module on ISS because of the stress fracture cracks they have found in the section where that port is located.

Russia is unable to use one of the docking ports of the ISS to its full extent due to cracks in the transitional chamber of the Zvezda module, the general designer of Russia’s Energia corporation, associate member of the Russian Academy of Sciences Vladimir Solovyov said on Monday. “The transitional chamber’s loss of airtightness is often mentioned these days. We are very fortunate the cracks are at the end. We shut down that compartment, thus losing one docking port, which narrows our opportunities somewhat. The crack is very insignificant, though,”

In other words, they have sealed the aft section of Zvezda to reduce further air leaks, thus also closing off access to the port.

The Russian portion of ISS presently has two docking ports on two different modules. When Roscosmos launches its Prichal docking hub in November, to be attached to Nauka’s port, they will then add four more ports.

This decision underlines the impending end to ISS’s life span. Zvezda is not the only old Russian module on ISS where stress fractures have been found. “In August they found cracks in the module Zarya, the oldest module on ISS.

Though the U.S. part of ISS shows no such problem, it is designed to rely on the Russian half for its operations. If Russia must shut down its modules then the station will not be able to function for much longer.

The U.S. will likely overcome some of these issues with the planned launch in ’24 of Axiom’s private commercial module to ISS, which will eventually evolve into an complete space station separate from ISS. For the Russians the pressure to design and launch their own new station has become more critical. Whether they can do it however is unknown. Russia has not built a new space station module in decades. Their new ISS module, Nauka, was built in the 1990s.

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Smoke and fire alarms in Russian ISS module Zvezda

8:54 am

In the middle of the night prior to a successful spacewalk by two Russian astronauts to begin the outfitting of the new Nauka module on ISS, fire alarms sounded in the Zvezda module, and both astronauts smelled smoke.

The incident, which the Russian space agency Roscosmos said happened at 1:55 a.m. GMT (9:55 p.m. EDT Wednesday) ahead of a scheduled spacewalk, is the latest in a string of problems to spur safety concerns over conditions on the Russian segment. “A smoke detector was triggered in the Zvezda service module of the Russian segment of the International Space Station during automatic battery charging, and an alarm went off,” Roscosmos said in a statement.

French astronaut Thomas Pesquet said “the smell of burning plastic or electronic equipment” wafted to the US segment of the station, Russian state news agency RIA Novosti reported, citing a NASA broadcast.

The Russian crew turned on a filter and, after the air was cleaned up, the astronauts went back to sleep, Roscosmos said.

It appears that because all the systems on the Russia portion of ISS continued to function normally, the Russians did no investigation. Or if they did, they have not revealed what they found. Nor has NASA provided any information.

In their history the Russians have experienced a number of fires on their various space stations. Some burned out without consequence (as it appears this recent one did). Others required aggressive action to bring them under control, as occurred on Mir several times. This history has apparently made the Russians somewhat nonchalant about such things.

That the issue was in Zvezda, however, which has a serious structural stress fracture problem in its hull, should be cause for a greater concern. Is this burn event related to the stress fractures? If I was an astronaut on board ISS I would surely want to know.

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New cracks discovered on a different Russian ISS module

12:38 am

Russian officials revealed today that their astronauts have discovered new cracks on a different Russian ISS module, dubbed Zarya.

“Superficial fissures have been found in some places on the Zarya module,” Vladimir Solovyov, chief engineer of rocket and space corporation Energia, told RIA news agency, according to Reuters. “This is bad and suggests that the fissures will begin to spread over time.” The Zarya module, also called the Functional Cargo Block, was the first component of the ISS ever launched, having blasted into orbit on Nov. 20, 1998, according to NASA.

Russians have now found what appear to be age stress fractures on both Zarya and Zvezda, the two oldest modules of ISS. More important, the Russians are finally admitting that the cracks are stress fractures, something they had earlier denied.

The need to launch new commercial American modules to ISS as quickly as possible has now become even more urgent. Axiom plans to do so, but its first module is not scheduled to arrive before ’24. It now looks increasingly that the Russian modules might not make it till then.

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More leaks found in Russian Zvezda module on ISS

10:34 am

Earlier this week Russian astronauts located and patched three more leaks in the 20+ year old Russian Zvezda module on ISS.

Prior to this week’s discovery, the recent patching done by Russian astronauts had reduced the air loss by about half. They need to do another seal test of Zvezda to see if these newer patches have reduced it further.

The report at the link from Russia is as usual very vague. No photos of any of the leaks have been released, by either Russia or NASA. No cause either has been described. This lack of information suggests that the leaks represent a more systemic problem, possibly related to stress fractures from age and wear. If so, it also suggests that Zvezda is nearing its pull-date. How this central module will be replaced from the station remains a major mystery.

Above all, this puts some urgency to the launch of newer modules, such as those being built by the private company Axiom.

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Air leak continues despite repairs on Zvezda module of ISS

9:48 am

According to a report today in the Russian press, the air in the Zvezda module of ISS continued to leak away slowly during a test, following this week’s repair of two cracks in the module’s hull.

At about 07:00 GMT on Saturday, ISS cosmonaut Sergei Ryzhikov told a specialist at the Mission Control Center, located near Moscow, that the pressure in the intermediate chamber of the Zvezda module was 678 millimetres of mercury. The pressure stood at 730 millimetres of mercury on Friday evening, right after the hatch of the compartment was closed. Thus, the pressure in the chamber decreased by 52 millimetres of mercury over 11.5 hours.

Based on the thorough nature of the two repairs, this leak must be coming from another very tiny leak that has not yet been detected. Though the leak is very slow and thus not an immediate threat to the astronauts on board, it suggests once again that the leaks are coming from stress fractures resulting from Zvezda’s 20-plus years in orbit. If so, the problem is very serious indeed. Zvezda is the central module for ISS. Replacing it will not be simple or easy.

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Russia: Air leaks fixed on Zvezda

9:30 am

According to the Russian state-run press, Russian astronauts have completed their repair work on the ISS module Zvezda and are about to seal the module to test their work.

“The crew of the International Space Station has completed the repair and recovery work on the hull of the Zvezda module. In the coming days, Sergei Ryzhikov and Sergei Kud-Sverchkov will close the hatches in the Zvezda module to check the atmospheric level,” the press office said.

Previous reports suggested the astronauts had located a total of two cracks, both now sealed.

The larger question however remains. Are the cracks stress fractures, and if so do they suggest that Zvezda’s 20-year-old hull is beginning to fail? The Russians have been very silent about these questions, though they have admitted the possibility once or twice, almost as an aside.

Nor has NASA been forthcoming. The American space agency has apparently joined the Russians in keeping this problem out of the news, at all costs. Once, the employees at NASA were Americans who demanded openness from Russia and from themselves. No more. Increasingly our government workers are indistinguishable from Soviet apparatchiks, whose main goal was to protect the government from bad press.

If Zvezda’s hull is failing then ISS faces some very serious engineering issues. They can be solved, but not by silence and sticking one’s head in the sand.

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Russian astronauts begin work to seal 2nd Zvezda leak on ISS

9:27 am

After successfully sealing the largest crack on the twenty-year-old Zvezda module on ISS, Russian astronauts have now begun work on sealing a second such crack.

The report, from Russia’s state-run news service TASS, is not very informative. It does not report the size of the leaks, their nature, and any other important conclusions the Russians have gathered about Zvezda’s overall condition and future, based on these cracks.

Nor has state-run NASA been very transparent on this subject, releasing little further information. The silence from these government entities about the cracks is very worrisome, as it suggests these fixes are merely bandaids on a more serious issue with Zvezda’s structure, and our dishonest and bureaucratic governments do not wish to reveal this fact to the public.

I hope I am wrong, but suspect I am not. If Russia follows its pattern for the past half century, they will provide a more detailed report only after the problem has been completely solved. If these patches are merely temporary fixes over a more serious problem, don’t expect that detailed report for some time.

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First air leak crack on ISS has not grown

9:25 am

A inspection of the first air leak crack that had been found and patched in the Zvezda module on ISS last year has found that it apparently not increased in size since then.

The size of a crack in the intermediate chamber of the Russian Zvezda module aboard the International Space Station (ISS) remains unchanged, cosmonaut Sergei Ryzhikov reported to Russia’s Flight Control Center on Wednesday. “It [the length] has not changed. As in the previous measurements, I do not see any changes,” Ryzhikov said during his talks with Mission Control broadcast on NASA’s website.

On February 23, the cosmonaut carried out work with a microscope to trace another possible air leak. The photos of the work were transmitted to Earth and the video from GoPro cameras will be sent via the Russian broadband communications system. After completing the work, the cosmonaut reinstalled the patch in the area of the crack.

This Russian report is decidedly unclear about some details. Though it appears the astronaut was using the microscope to inspect another leak, he also apparently removed the patch on the first leak to check the crack for any changes, then replaced it. How one removes and replaces such a patch is a puzzle however. Such things are generally not removable.

No matter. The important detail is that the crack has not grown. If it was a stress fracture the recent dockings of spacecraft to the nearby port might cause it to grow. That it has not is good news.

The bad news is that the inspection did not find the second small leak that is thought to be in this same Zvezda module.

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New leak located in Zvezda on ISS

5:57 pm

Russian astronauts have located the suspected new leak location in the Zvezda module on ISS, and also think there might be another, as yet unlocated.

The specialists have discovered one more crack at the International Space Station and suspect that yet another one exists, ISS Russian Segment head Vladimir Solovyov told Rossiya-24. “So far, we have found one place and suspect another, where as some kind of leak exists. We must bring a powerful microscope on a cargo spacecraft and use to examine this place. We are not totally certain so far,” Solovyov said.

These two leaks are in addition to the one inch crack that caused last year’s leak and has been sealed.

All are pointing strongly to stress fractures in this section of Zvezda, one of the station’s oldest modules at twenty-plus years. The leaks are apparently located in the aft section where ships dock to Zvezda, with over a 100 dockings there since launch.

If the cracks and leaks are caused by stress fractures, the life span of Zvezda is now quite limited. It might be possible to seal the cracks and protect the module from further breaks by ending dockings at its port, but I suspect that will not work. Moreover, if I remember correctly Zvezda has the engines that are used to periodically raise ISS’s orbits. If the stress of firing those engines is too risky than another way must be found to maintain the station’s orbit.

In a few years the private company Axiom will be launching its own modules to ISS, designed in the long run to separate from the station and function independently. If NASA and Axiom are smart, they will make sure this new module matches Zvezda’s capabilities, thus making the Russian module redundant and actually superfluous.

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Air leak in Russian section of ISS continues

8:27 am

Dmitri Rogozon, the head of Roscosmos, yesterday announced that they will be sending to ISS special equipment for investigating a new air leak in the Russia section of ISS.

This apparently is not the 1-2 inch long crack in the Zvezda module that leaked previously and was found and sealed. Moreover, the article at the link admits that their astronauts found no sign of damage on the outside of Zvezda when they did a space walk in November, suggesting that this first leak was not caused by a micrometeorite hit.

All the known facts so far strongly suggest that the leaks are because of Zvezda’s 20-year-old age, and might be stress fractures caused by the three dozen or so dockings and undockings that have occurred there since its launch.

That the Russians are being so vague about the entire matter reinforces that conclusion. They have never released an image of the first leak, and provided no details about the equipment being sent to the station.

And if Zvezda is beginning to crack due to age, I am not sure what repairs they can do to stop it.

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Russian company proposes new Russian space station post-ISS

9:27 am

Energia, the division in Roscosmos that manages the Russian manned program, including its share of ISS, has proposed that Russia build its own space station after 2025, and the reasons it gives strongly suggest they are worried about the condition of their 20-year-old and leaking Zvezda module.

The International Space Station’s systems are likely to keep breaking down after 2025, Energia company, which manages the Russian module, said and suggested building a national station instead. “Russia has commitments regarding the ISS through 2025. Several elements are already seriously damaged and about to stop functioning. Many of them are impossible to replace. After 2025, we expect many ISS elements to start breaking down en masse,” the deputy director-general of Energia, Vladimir Soloviev, said at a meeting of the Russian Academy of Sciences. [emphasis mine]

They don’t mention Zvezda by name, but the highlighted words point to it. Assuming the persistent leaks in the module are related to stress damage and age, this statement is recognizing publicly that replacing Zvezda is very difficult, or impossible, and that it is on the verge of complete failure.

Whether Russia has the money or resources to get another station built soon after 2025 is questionable, however. If they do decide to go it alone, I doubt they could launch a replacement before 2030, at the earliest, and likely much later than that.

If they do end the partnership with the U.S., it is unclear what happens to ISS. If the Russians choose to undock their portion of the station it will leave ISS somewhat crippled. It has been my impression that without all of the environmental systems in the Russian half, ISS cannot function. This might no longer be true, and will likely not be true with the planned arrival of Axiom’s private modules by the mid-20s. Timing however of all this remains critical.

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Despite permanent repair of crack, air still leaking from Zvezda

10:11 am

According to a Russian news report yesterday, air is still leaking from the Zvezda module of ISS, despite the permanent repair of the crack earlier this week.

Earlier, the crew locked the hatches into the intermediate chamber. The Mission Control asked whether the crew had measured the pressure before the hatch into that chamber was opened. The crew reported that the pressure went down considerably in the smaller part of the compartment while it remained isolated from the rest of the station by an airtight hatch. “The pressure in the intermediate chamber went down from 723 mm of the mercury column to 685 millimeters,” Ryzhikov said.

The report is poorly written, and is unclear on the exact date this air test was done. It is therefore possible the test was done prior to the permanent repair.

If however the air is still leaking, this suggests there might be more than one leak point in that part of Zvezda. According to this same story, the two Russian astronauts during their spacewalk on November 18th took pictures of the exterior area of Zvezda where the leak is located, and noted no exterior damage.

All these facts point to a very serious problem. If there was no exterior damage, it means the leak was probably not caused by a micrometeorite hit (though closer more extensive observations as well as a review of the photos might still conclude otherwise). The fact that the leak is continuing after the permanent repair suggests there is another leak, in the same part of Zvezda. That section is also a docking port, and would have experienced the most stress during the several dozen dockings that have occurred since Zvezda was launched in 2000.

These facts therefore suggest stress damage and aging as the cause, which means the problem will only get worse no matter what method is used to seal any future leaks.

One quick solution that would work, at least for awhile, would be to close the hatch on this intermediate chamber, and do no more dockings to it. This at least would seal the station from atmosphere loss, and reduce the stress on this section of Zvezda. Whether Progress freighters, which use this port, can use another port, or will have a more limited ability to dock, is not clear, however.

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Russian spacewalk to inspect leak in Zvezda

8:13 am

The Russian spacewalk to inspect the outside location of the air leak in the Zvezda module on ISS has now been scheduled for November 18, 2020, and NASA will be providing a live stream.

Live coverage of the Russian spacewalk will begin at 8:30 a.m. EST on NASA Television and the agency’s website. The spacewalk is expected to begin about 9:30 a.m.

Ryzhikov, designated extravehicular crew member 1 (EV1), will wear a Russian Orlan spacesuit with red stripes, and Kud-Sverchkov will wear a spacesuit with blue stripes as extravehicular crew member 2 (EV2). This will be the 47th Russian spacewalk for assembly and maintenance of the station.

During the spacewalk, Ryzhikov and Kud-Sverchkov will first conduct leak inspections outside the hatch, as this will be the first spacewalk using the Poisk module for its purpose as an airlock. Next, they will relocate an antenna from another module, the Pirs docking compartment, to Poisk, the first in a series of tasks over the course of several spacewalks that will prepare Pirs for decommissioning, undocking, and disposal. The Earth-facing Pirs will be replaced by the new Russian Multipurpose Laboratory Module, named “Nauka,” Russian for “science,” which is being prepared for launch at the Baikonur Cosmodrome in Kazakhstan.

What they find could have a significant impact on the future of the space station.

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Russians aim for Dec for fixing ISS leak permanently

8:23 am

The Russians announced yesterday that they plan the full and permanent repair of the small inch-long crack leaking air on ISS to occur in December, after required material is shipped to the station.

According to the official, the crack was the width of a hair and located in a hard-to-reach spot of Zvezda’s shell.

Solovyov did not specify the spacecraft that will deliver the sealing materials to the ISS, but the only one scheduled to fly in December is Cargo Dragon, a reusable freight spaceship of US private company SpaceX. The soonest flight of a Russian cargo spacecraft — Progress MS-16 — has been postponed until December 2021.

They also plan a spacewalk in the next two weeks to inspect the exterior of the Zvezda module where the crack is located.

I have yet to see an image of the crack itself. Why none has been made easily available is somewhat puzzling.

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Russian astronaut: Crack on ISS could be from “external impact”

10:48 am

Russian astronaut, Sergei Ryzhikov, today noted that to him the 1-inch crack causing the leak on ISS appeared to have been caused by an “external impact.”

Speaking with Flight Director of the Russian segment of the ISS Vladimir Solovyov, Russian cosmonaut Sergei Ryzhikov said: “If you take a closer look at the picture, there are changes of color in the middle of the crack.”

“We suspect an external impact,” Ryzhikov said adding that the place of the suspected impact should be examined during the crew’s next spacewalk, which is scheduled for November 18.

This conclusion is different than that expressed yesterday by another Russian astronaut, who suggested the crack was from age and wear and tear of the twenty-year-old Zvezda module.

Either way, an inspection of the exterior point of the crack is essential in order to permanently seal it, and that inspection will tell us one way or the other the cause of the crack.

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Russian astronaut: ISS crack could be result of Zvezda module’s age

7:31 am

A Russian astronaut just returned from ISS admitted during a press conference that the recently located crack on the 20-year-old Zvezda module that was the source of the long-term slow leak could be the result of the module’s age.

“Twenty years are actually an absolute record for all space stations now. And we see now that something is changing and something requires greater [attention]. Again, if we go back to the leak, the hull is already beginning to give cracks and scratches somewhere, that is, we see the limits [of the ISS structure’s service life],” [cosmonaut Ivan Vagner] said.

The crack has been sealed temporarily, with a more permanent seal put in place after the nearby docking port is cleared and the hatches closed and out of the way.

If Russian astronauts are noticing wear and tear in Zvezda that is bad enough to cause “cracks”, this raises some very serious issues for ISS’s future, as replacing that module on ISS will be complicated and expensive, and at this point no one has even begun planning such an replacement.

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Leak on ISS still leaking even after being temporarily sealed with tape

9:27 am

Even though Russian astronauts have now patched with Kapton tape the 1-inch crack where they thought the leak in the Zvezda module on ISS was located, the loss of air has continued, and even increased.

The pressure in the Zvezda module of the International Space Station (ISS) keeps lowering, although the fissure was patched with Kapton tape, and even faster than before the fix, the crew told the ground control on Tuesday, as broadcast by NASA.

They are going to add more tape to the patch and see if this seals the leak.

Meanwhile, there has been little discussion about the nature of this 1-inch crack. Was it caused by a micrometeorite, or is it a stress fracture? And where exactly is it, and does that location help explain it?

Inquiring minds need to know!

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Russian astronauts repair oxygen regeneration unit

10:26 am

Russian astronauts on ISS have successfully repaired the oxygen regeneration unit on the Zvezda module.

From the TASS article was this additional information:

The Elektron-VM oxygen supply system developed by Russia’s Research and Design Institute of Chemical Machine-Building (NIIChimMash) has been operational aboard the space station since its creation. The system can generate from 25 to 160 liters of oxygen per hour and additionally from 50 to 320 liters of hydrogen per hour. In April 2010, it took the ISS crew several days to fix the broken system.

No word yet on any new information on the “fracture” that is causing the slow leak.

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Leak on ISS traced to “fracture”

9:43 am

Not good news: According the Russian news source TASS, Russian astronauts have pinpointed the location of the slow leak on ISS to ” a fracture in the intersection compartment of the Russian Zvezda module.”

The astronaut also called it a “scratch,” which means the fracture is not yet confirmed. They will do more testing to find out if this is the leak source in the coming days.

If it is a fracture, the ramifications could be very serious. It appears the “intersection compartment” is the area where the aft docking port is located, which is also the area where many Progress freighters have docked in the twenty years since Zvezda was launched. Thus, this could be a stress fracture that can only get bigger with time. Its location might also preclude further dockings at this port, limiting arrivals of future Progress cargo ships.

Fun fact: They pinpointed this location using a floating tea bag.

The tea bag’s sway in zero gravity conditions towards the air leak overboard the space station was registered by cameras, the cosmonaut said. “We believe that we have really identified the probable leakage area. We have distributed a tea bag [in the Zvezda module] before closing the transfer chamber,” Ivanishin said.

The tea bag’s movement was recorded, the Russian cosmonaut said.

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Zvezda both leaking and heating up

9:23 am

A Russian news source today reported that the temperature in the ISS module Zvezda has been increasing even as air has been leaking slowly from it.

The article provides little additional detail, other than saying that “normal temperature should be restored” by today.

Why the module should be warming as it slowly leaks air is puzzling. Either way, as this is a module that has been in space for twenty years and is also a key component in the station’s operations, locating the leak is crucial. It might simply be caused by a micrometeorite hit, which can be easily patched. Or it could be caused by something more fundamental, caused by the module’s age, and thus more difficult, possibly even impossible, to fix. If so, the sooner engineers know the better.

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