International Space Station (ISS / Alpha)

GW Johnson · 2024-10-17 08:38:33

More on the leak in the ISS:

From the Space.com article summarized in AIAA’s “Daily Launch” for 10-17-2024:

ISS leaks among 50 'areas of concern' for astronaut safety: report
News
By Elizabeth Howell
published yesterday

NASA and Russia are working together on addressing the situation in the wake of an Office of the Inspector General report last month.

NASA and its Russian counterpart have identified 50 "areas of concern" related to a long-running leak aboard the space station, a media report states.

The leak has been ongoing since 2019 in the Russian segment of the International Space Station (ISS) and was the focus of a new report from NASA's Office of the Inspector General (OIG) published in September. While NASA and Roscosmos are addressing the leak, it remains a top "safety risk" for astronauts on board, the OIG report stated.

NASA officials, speaking in an exclusive with the Washington Post, said they are tracking four cracks and 50 other "areas of concern" on the ISS. The cracks have "all been covered with a combination of sealant and patches" by Roscosmos, NASA noted in a statement to the newspaper, and fixes are ongoing. Still, the leaking area is the top risk, at a 5 on a scale of 5, in NASA's internal risk assessments, the OIG stated.

"We have conveyed the seriousness of the leaks multiple times, including when I was in Russia earlier this year," associate administrator Jim Free added in an interview with the Post. Since the leaks are adjacent to a hatch, Free added that Roscosmos acquiesced to a NASA request to close the hatch as much as possible: “We've come to a compromise that they close it in the evening."

NASA astronauts also remain on the U.S. side of the orbiting complex to be close to their escape vehicles, in case of the need of evacuation, the agency noted in its statement to the news outlet. That said, NASA has stressed repeatedly that the leak poses no immediate threat to astronauts.

"Not an impact right now on the crew safety or vehicle operations, but something for everybody to be aware of," ISS program manager Joel Montalbano said in a news conference in February 2024 when the leak temporarily increased to 2.4 pounds per day, up from a historic low of 0.2 pounds per day.

The leak has been ongoing for five years and patches have been ongoing since it was first uncovered; agency officials noted in a Sept. 27 livestreamed briefing that repair work reduced the high leak observed in April 2024 by roughly a third.

The escaping air originated in a service module transfer tunnel in Russia's Zvezda module that launched in 2000. Zvezda, along with the rest of the ISS, is aging and requires maintenance to keep going in orbit. The ISS is supposed to last until 2030 to serve both NASA's staffing needs, and also to provide commercial low Earth orbit research. In the following decade, NASA hopes to have a set of commercial space stations ready to take over operations.

NASA's OIG is tracking several other risks that could imperil keeping the ISS going that long, ranging from a sudden micrometeoroid strike to supply chain issues.

SpaceX has been tasked to build a large Dragon-type spacecraft to remove the ISS from orbit, in a contract awarded by NASA earlier this year. The OIG stated it will be looking to learn more about the schedule, costs and risks associated with the new vehicle and the deorbiting plan.

My take on it:

The description of treating the 5 cracks says sealant and patches have been applied. That is NOT the way to fix cracks originating from cyclic loading. The critical step of crack stress relief presumably got left out, because there is no mention of it anywhere in the article. That step is to find and to drill-out the tip ends (plural! there are two ends to every crack!) to relieve the stress. Then (and only then) do you apply sealants and/or patches. Otherwise, the crack just keeps growing longer with time, right out from under your sealants and patches.

This "fix" for fatigue cracks has been known in aircraft design since the early 1950's. It was actually applied (and it worked) to the wing spars of the Lockheed Electra-II airliners, long before they ever became the Navy's P-3 fleet. Somebody (a reporter?) ignorant of this "fix" questioned the technician doing it. The technician replied "did you ever see toilet paper tear on the dotted line?" And THAT is the true origin of that old tale!

So, either both NASA and Roscosmos are ignorant of design practices for dealing with fatigue in duralumin alloys that date back almost 7 decades (which I doubt), or Roscosmos just wants to limp along risking a blowout rather than spending what it takes to fix the trouble. Which is either drill out the cracks or replace the module. What's truly disappointing is that NASA is not calling them out over this.

And y'all already bloody well know I am right about this! Any pressure vessel with growing holes in it, will eventually burst suddenly. Y'all know that, too. The risk here is a dead crew from a sudden explosive decompression that sucks all the air out of the station in only several seconds! Close the damned hatch, and keep it closed! Or fix the bloody problem, but do it right!

I hope someone at NASA reads this post!

GW

Update 10-18-2024:

If you don't believe the Zvezda module cracking apart would depressurize the station suddenly, killing the entire crew, then consider this. Think about the "PA kick load" that happens like an impact force when two sections of a pressure vessel part from each other. ISS operates at about 1 std atm internal pressure, which in US units is 2116 lb/sq.ft. I don't know the diameter in Zvezda where the cracks are located, but let's just presume it to be about 6 feet. If circular, the cross sectional area is near 28.3 sq.ft. The PA kick load is pressure x area upon which it acts, or some 59,830 lb = 27.1 metric tons-force. Bigger diameter, bigger force, proportional to diameter squared! Twice the diameter is a 4 times bigger force!

The effect that load has upon adjacent structures is a sudden impact, not a gently-applied steady load, so you must at least double that value for estimating stresses in related structures, to around 120,000 lb or 54.3 metric tons-force! A sudden impact that large will break up much of the station, tearing module from module, and letting all the air out of them, pretty much all at once! No one in the crew will have time to shelter anywhere!

And THAT is why I think the risk of these propagating cracks is so severe! And so urgent to address!

Last edited by GW Johnson (2024-10-18 08:34:29)

GW Johnson · 2024-10-18 08:36:01

For you skeptics about the leaking cracks in the Zvezda module, I just added a couple of paragraphs to post 726 just above, describing the consequences if that module busts open.

GW

tahanson43206 · 2024-10-18 09:11:21

For GW Johnson!

There is an opportunity for you to clarify if the leak is in the Zvezda module, or in a separate part that could be cut off.

Air leaks
Since September 2019, the Zvezda module has been experiencing a worsening air leak. The source appears to be microscopic structural cracks within the small tunnel connecting Zvezda to a docking port used by Progress cargo spacecraft. The leak rate has increased from initially less than 1 pound (0.45 kg) per day to 3.7 pounds (1.7 kg) per day as of April 2024. While both NASA and Roscosmos suspect internal or external welds, the root cause of the leaks remains unknown. The agencies have said that if the leaks reach an untenable level, they plan to close the hatch leading to the tunnel, however that would result in the loss of the docking port. Internally, NASA has classified the leaks as a high-risk threat to spaceflight activities, potentially leading to "catastrophic failure." However, Roscosmos has expressed confidence in their ability to monitor the leak and close the hatch before it becomes unmanageable.[30][31]
Interior

My reading of the Wikipedia update is that the Russians would like to keep their docking port.

My question is: Can the tunnel be severed from Zvezda?

I understand there is a hatch to the tunnel that can be closed.

If the hatch to the tunnel is closed and the tunnel is severed from the hatch, then the opportunity (presumably) exists to connect a replacement tunnel and re-install the docking port.

(th)

GW Johnson · 2024-10-18 14:15:58

Here's a quote from the article I quoted in post 726: "The escaping air originated in a service module transfer tunnel in Russia's Zvezda module that launched in 2000."

I do not know details, but the words would indicate the transfer tunnel is part of the Zvezda module.

Yes, there is a hatch to the Zvezda module that can be closed. Closing it eliminates access to a docking port that is currently often used. The kick force happens whether that hatch is open or closed, if the module is pressurized.

As I understand it, the Russians have agreed with NASA to close that hatch, but only "at night".

GW

kbd512 · 2024-10-18 21:24:22

Someone needs to tell the Russians that it's time to set Condition Zebra before the entire station is lost to an explosive decompression event. Now that we know where the source of the problem is, it would be stupid to kill everyone aboard because it's "inconvenient" to dog all hatches.

tahanson43206 · 2024-10-19 04:41:45

There are Russians and there are Russians....

The situation is far more difficult to solve than it needed to be from a technical point of view.

The decision by Mr. Putin to invade Ukraine has made it far more difficult to solve this problem as just humans.

If part of the problem is cash flow in Russia (and it may well be due to allocation of resources for military purposes) the the US might be able to pay for a replacement tunnel. If we were still in the Yeltsin days such a cooperative effort might be possible.

Such a cooperative undertaking may still be possible, if the right human personalities are available.

This is 5% a technical issue, and 95% a human relationships problem.

(th)

GW Johnson · 2024-10-19 13:37:16

It's a problem driven by money and politics, pure and simple! Neither of which is a proper basis for making space crew safety decisions, as we already know from two dead shuttle crews.

GW

tahanson43206 · 2024-10-19 14:24:47

For GW Johnson re #732

To say that human relationships are based upon money and politics is to over simplify a complex set of currents in "human space"

It appears to me that some people are motivated by money, but many are motivated by other interests.

A scientist who invests a lifetime learning everything there is to know about a species of insect is NOT motivated by money.

A mother who cares for a child (or any family member) is NOT motivated by money.

There are certainly humans who are motivated by emotions that get translated into politics.

However, I expect that neither the Americans nor the Russians on the ISS are motivated by either of these.

Human society appears (to me) to include individuals who operate under a wide range of motivations.

In the case of the problem we seem to see at the ISS, of Russians wanting to keep using a dangerous piece of equipment, it seems to me that the services of a true diplomat are called for.

Whatever the motivations of the players may be, the (hypothetical) diplomat we need would be able to find solutions that meet the needs of the participants, and if some investment on one side or the other is needed, so be it.

I would imagine that the Russians in the ISS community are reluctant to experience total decompression, but whatever their feelings may be are ruled by superiors on the ground, and ** there ** the motivations become more complex.

If the need is to keep a docking port working as long as the Russians need it, then a solution that might work for them would be finding a way to replace a failing docking port with a new one. It might even turn out that a liner through the existing tunnel would solve the leak problem. My assumption here is that this is a human relations problem primarily, with about 5% technical issue to be solved, if good will can be mustered to allow effective thinking.

Update:
The proposed liner for the interior of the tunnel might be fabricated in 120 degree sections so they can fit through the existing docking port. the liner section could then be bolted together as a first step in installation, and then welded to each other, and to the tunnel.

The tunnel need not bear the stress of the 90 minute temperature swings, if the existing tunnel remains in place outside the liner.

(th)

GW Johnson · 2024-10-20 10:07:29

I cannot argue with the long list of human motivations in the previous post (733). I would only add that all the different people to which those motivations ascribe are not the people who make decisions in the space business. Those are politicians and corporate executives.

And the dominant motivations for those two types of people who do make the decisions are exactly the politics and money that mentioned in my earlier post (732) as the root cause of the current ISS problems.

GW

GW Johnson · 2024-11-06 09:19:43

From the 11-6-2024 “Daily Launch”:

ARS TECHNICA

After 31 cargo missions, NASA finds Dragon still has some new tricks

As space missions go, the latest Cargo Dragon one was fairly routine, ferrying about 6,000 pounds (2,700 kg) of cargo and science experiments to the space station. However, there is one characteristic of this flight that may prove significant for NASA and the future of the space station. As early as Friday, NASA and SpaceX have scheduled a "reboost and attitude control demonstration," during which the Dragon spacecraft will use some of the thrusters at the base of the capsule. This is the first time the Dragon spacecraft will be used to move the space station.

My take on it:

If Dragon can be used for re-boost and debris avoidance, docked to an American-style docking port, then there is an alternative to the Russian-style docking port on the leaking Zvezda module. Soyuz craft on the Russian docking port have so far has been the only means of re-boost and debris avoidance. If this works, there is no excuse not to close the hatch into the leaking tunnel in Zvezda, and letting the cracked tunnel depressurize.

Problem: doing that then deprives the station of its ability to receive Soyuz and Progress craft.

NASA and Roscosmos will need to send up some kind of adapter to fit Soyuz and Progress craft to the American-style docking ports. Otherwise, they lose the crew transport capability of Soyuz, and the cargo transport of Progress. That deprivation and docking compatibility problem is why the Russians have so far resisted closing that hatch.

GW

GW Johnson · 2025-06-13 09:16:08

I just saw news reports that the next private crew launch to be sent to the ISS has been delayed yet again, this time by renewed concern about the chronic air leak in the Zvezda module that has the Soyuz docking port.

They've been patching again, and said they have the leak rate stabilized (at about a kg of air lost every day), and want to watch it for a while, before they let that Axiom crew come to the station. The implication, unstated in the news reports, is that the leak rate got worse, prompting more repair attempts. NASA and Roscosmos cannot agree on what caused this, or on the decompression threat it poses, but the reports do say they keep the hatch to this module closed unless there really is a docking operation going on.

Here's the kicker: when they are using the module, the hatch between the Russian side and the rest of the station is kept closed. THAT ought to speak VOLUMES about the risk of using over-age modules in space. I would infer that new cracks keep appearing, and getting patched after they are found by the greatly-increased air leaks they produce. Sooner or later, this module is going to suddenly split wide open. You literally do not want spreading cracks in pressure vessels.

GW

Last edited by GW Johnson (2025-06-13 09:17:24)

SpaceNut · 2025-09-24 14:57:49

NASA will say goodbye to the International Space Station in 2030, and welcome in the age of commercial space stations

In 2030, the International Space Station will be deorbited: driven into a remote area of the Pacific Ocean.
I'm an aerospace engineer who has helped build a range of hardware and experiments for the ISS. As a member of the spaceflight community for over 30 years and a 17-year member of the NASA community, it will be hard for me to see the ISS come to an end.
Astronauts performing research inside the space station and payload experiments attached to the station's exterior have generated many publications in peer-reviewed science journals. Some of them have advanced our understanding of thunderstorms, led to improvements in the crystallization processes of key cancer-fighting drugs, detailed how to grow artificial retinas in space, explored the processing of ultrapure optical fibers and explained how to sequence DNA in orbit.
In total, more than 4,000 experiments have been conducted aboard the ISS, resulting in more than 4,400 research publications dedicated to advancing and improving life on Earth and helping forge a path for future space exploration activities.
The ISS has proven the value of conducting research in the unique environment of spaceflight—which has very low gravity, a vacuum, extreme temperature cycles and radiation—to advance scientists' understanding of a wide range of important physical, chemical and biological processes.
Keeping a presence in orbit
But in the wake of the station's retirement, NASA and its international partners are not abandoning their outpost in low-Earth orbit. Instead, they are looking for alternatives to continue to take advantage of low Earth orbit's promise as a unique research laboratory and to extend the continuous, 25-year human presence some 250 miles (402 kilometers) above Earth's surface.
In December 2021, NASA announced three awards to help develop privately owned, commercially operated space stations in low-Earth orbit.
For years, NASA has successfully sent supplies to the International Space Station using commercial partners, and the agency recently began similar business arrangements with SpaceX and Boeing for transporting crew aboard the Dragon and Starliner spacecraft, respectively.
While these stations are being built, Chinese astronauts will continue to live and work aboard their Tiangong space station, a three-person, permanently crewed facility orbiting approximately 250 miles (402 km) above Earth's surface. Consequently, if the ISS's occupied streak comes to an end, China and Tiangong will take over as the longest continually inhabited space station in operation: It's been occupied for approximately four years and counting.
It will be several years before any of these new commercial space stations circle Earth at around 17,500 miles per hour (28,000 kilometers per hour) and several years before the ISS is deorbited in 2030.
So while you have a chance, take a look up and enjoy the view. On most nights when the ISS flies over, it is simply magnificent: a brilliant blue-white point of light, usually the brightest object in the sky, silently executing a graceful arc across the sky.
Our ancestors could hardly have imagined that one day, one of the brightest objects in the night sky would have been conceived by the human mind and built by human hands.

SpaceNut · 2025-09-25 14:47:52

https://www.nasa.gov/wp-content/uploads … 90ad510f08

Approximately 2.5 year mission
 Earth‐to‐Mars transit: ~6 months
 Mars surface stay: ~18 months
 Mars‐to‐Earth transit: ~6 months
 A 5‐yr shelf life requirement is expected
 Food prepositioning may be required to accommodate high mass and volume
of food
 Production and stowage will take time due to volume
 The current food system would become unacceptable before the mission
ended
 No refrigerators or freezers available for food preservation

GW Johnson · 2025-09-26 09:12:55

From the AIAA email newsletter “Daily Launch” for Friday 9-26-2025.

AEROSPACE AMERICA
NASA says it’s ‘no longer obligated’ to use Dream Chaser for ISS resupply

NASA announced Thursday it is “no longer obligated” to use the Dream Chaser spaceplane in development by Colorado company Sierra Space for cargo resupply missions to the International Space Station. Both NASA and Sierra said testing and development of the first Dream Chaser, known as Tenacity, would continue toward a test flight planned for 2026, but that flight would be a “free-flyer, demonstration mission.”

----
My take on it: from a technical viewpoint, this was a stupid decision on NASA’s part, driven by the current politically-driven chaos all across our government. NASA needs Dreamchaser, because Starliner is not going to go anywhere. That only leaves them Dragon!

Boeing would just as soon kill Starliner as the money-loser it has been. The only thing holding them back is the costs imposed if they fail to deliver at least one “certified” flight on their contract.

ISS is due to end sometime in 2030. That’s only about 4 to 5 years away. At a crew flight every 6 months, that’s only 8 to 10 more crew flights, and about half of those will fly on the Russian craft. So that’s 4 to 5 flights left for the US to ISS, and Starliner would have only a piece of that (1 or 2 flights), because SpaceX’s Dragon is doing such a good job already.

Even if the Russians never flew another flight, that’s still only 8 to 10 more flights to ISS by the US, with the majority going to the well-proven Dragon. So it’s still only maybe 3-4 flights for Starliner. There is just no money to be made there for Boeing.

As for the follow-on stations, there is Dragon, and Sierra Space will want to offer Dreamchaser for some of those. Why would Boeing want to offer Starliner for that follow-on market, even if they successfully fix it? Especially with the tarnished reputation it already has? Nobody is going to want to ride in it!

GW

Last edited by GW Johnson (2025-09-26 09:13:54)

SpaceNut · 2025-09-26 16:36:55

here is another https://www.sierraspace.com/commercial- … e-habitat/

https://www.forbes.com/sites/brucedormi … prototype/

GW Johnson · 2025-09-28 13:59:28

I have not kept up with everything that has been going on. Is Sierra Space the inheritor of the Bigelow inflatable technology? Those designs on the site via your link surely do look like it! Right down to the apparent 1 m thickness around the window openings. Which is not only thermal insulation and meteoroid/debris protection, but also some degree of protection against solar flare radiation.

If you put such a station into Earth orbit somewhere below the Van Allen belts, you are still largely protected from too much solar flare radiation by the Earth's magnetic field. If you want to explore the effects of the radiation and how effective your design is at protecting against it, Van Allen belt radiation is a fair-to-middling surrogate for solar flare radiation. Just put your experimental station (or at least a module) into an orbit that takes it inside the belts. Excepting the South Atlantic anomaly, the nominal lower "edge" of the Van Allen belts is about 900 statute miles = 1600 km altitude. It's a very fuzzy boundary.

I also see that nobody but me is yet proposing to couple a linear stick of such modules together, into a "baton", and then spin it end-over-end for artificial gravity. You can build the decks into the cores of the inflatables as fold-out items. But in baton mode, you can explore the effects of multiple levels of partial gee gravity, all the way up to (and beyond) 1 full gee at the outer 2 modules' outermost decks. That is an experimental answer that we must have for long duration manned missions. And we have ZERO in the way of an answer yet! Which is an unconscionable lack! Traceable directly to nearly all of NASA's significant projects being pork-barrel items dictated by Congress. Since Apollo, actually!

GW

Last edited by GW Johnson (2025-09-28 14:07:35)

SpaceNut · 2025-09-29 10:06:53

Nasa is ready to throw it away and yet we have no replacement or even growth of such a network of orbiting habbitats to make use of.

The ability to loft goods to the station for the astronaut scientists seems to almost skipped a beat, Carrying Supplies For ISS Astronauts, NASA's Cygnus XL Spacecraft Suffers Engine Malfunction

Cygnus XL spacecraft experienced engine trouble during its journey. The mishap temporarily delayed the delivery of more than 11,000 pounds of supplies to astronauts aboard the ISS. When the spacecraft's main engine shut down earlier but the Cygnus XL and its nearly five tons of supplies made it to ISS
What did those 11,000 pounds of supplies contain? Essential materials for research, maintaining the ISS, and various other provisions to support the ISS crew through early 2026. This stuff is priceless to those ISS astronauts, and the loss of it would have been a major blow.
Malfunctions are an inevitable part of supply chain logistics in space
For now, the ISS crew is no doubt happy to have all that cargo, which includes food, oxygen, and nitrogen, plus spare parts for the station's waste filtering system that gives them their fresh drinking water.

GW Johnson · 2025-09-29 14:25:09

It's worn out, Spacenut. Particularly the Zvezda module, which keeps cracking and leaking. Sooner or later, something is going to split wide open, and decompress the entire station, killing the entire crew.

It's not pressurization / depressurization cycles like an airplane, but hot-to-cold thermal cycling every orbit. Sunlight vs shadow. That's roughly 4000 cycles per year, for over 2 decades now. 80,000 + cycles? A lot of airplanes were only designed for 40,000 cycles. Same aluminum structures! Unlike most other metals, aluminum does not seem to have a low stress value below which fatigue life is infinite. Or if it does, that value is very low indeed.

You are correct in pointing out that NASA has no valid follow-on space station plan of any credibility! The powerful senators that dominate what NASA's big projects are, are simply too stupid to understand what is really needed next. We do not elect our best and brightest to Congress. Or had you not noticed that?

Myself, I think it is way past time we-the-people got Congress out of the business of micromanaging NASA projects for pork barrel outcomes instead of real space program outcomes. Congress has been doing that to NASA since Apollo. We have NOT seen a logical next-project-notion for NASA, since John F. Kennedy set the moon-landing-objective-before-1970, way back in 1961.

As for this last Cygnus cargo flight, word has it that the trouble was in the flight control software, not the actual engine system hardware. Still, that kind of nonsense is no longer tolerable. Starliner showed that lesson for certain and for true, plus the other lesson about not being so damned cheap.

GW

Last edited by GW Johnson (2025-09-29 14:38:53)

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#726 2024-10-17 08:38:33

Re: International Space Station (ISS / Alpha)

#727 2024-10-18 08:36:01

Re: International Space Station (ISS / Alpha)

#728 2024-10-18 09:11:21

Re: International Space Station (ISS / Alpha)

#729 2024-10-18 14:15:58

Re: International Space Station (ISS / Alpha)

#730 2024-10-18 21:24:22

Re: International Space Station (ISS / Alpha)

#731 2024-10-19 04:41:45

Re: International Space Station (ISS / Alpha)

#732 2024-10-19 13:37:16

Re: International Space Station (ISS / Alpha)

#733 2024-10-19 14:24:47

Re: International Space Station (ISS / Alpha)

#734 2024-10-20 10:07:29

Re: International Space Station (ISS / Alpha)

#735 2024-11-06 09:19:43

Re: International Space Station (ISS / Alpha)

#736 2025-06-13 09:16:08

Re: International Space Station (ISS / Alpha)

#737 2025-09-24 14:57:49

Re: International Space Station (ISS / Alpha)

#738 2025-09-25 14:47:52

Re: International Space Station (ISS / Alpha)

#739 2025-09-26 09:12:55

Re: International Space Station (ISS / Alpha)

#740 2025-09-26 16:36:55

Re: International Space Station (ISS / Alpha)

#741 2025-09-28 13:59:28

Re: International Space Station (ISS / Alpha)

#742 2025-09-29 10:06:53

Re: International Space Station (ISS / Alpha)

#743 2025-09-29 14:25:09

Re: International Space Station (ISS / Alpha)

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