NASA reveals that it and Russia disagree about the danger posed by the airleak on ISS
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.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
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.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Should the International Scam Station break up unexpectedly it will be a huge black eye for everyone involved.
An even worse PR outcome might be if the Russian side gradually became uninhabitable, and the Cosmonauts had to either leave or take shelter with the Astronauts, perhaps even unable to reach their own ships to evacuate.
The given leakage rate seems alarmingly high, and a quick run of the numbers suggests concern. I am curious why the data is not given in Metric. I noted the same thing in ‘The Martian’ film. Imperial it is, then.
The habitable volume of Zvezda is given as 1650 ft^3. Leakage rate per 24/hr period looks to be around 3 lbs/day. Atmo in ISS is given as Earth ambient at Standard Temperature and Pressure (STP). Air at STP masses 0.07967 lbs/ft^3. Some arithmetic yields about 37.5 ft^3/day reverting to Space, or a little over 2% of the given volume.
I know that the Russian side has a greater volume than the one module, but even if you cut the volume ratio in half, that’s a lot of difficult-to-replace resource. Other variables constant, loss would likely follow a natural log curve as pressure decreased, perhaps reaching an ‘acceptable’ level, if the atmospheric pressure was not reduced below minimums.
Blair Ivey: The air loss is actually not the main concern. The main concern is the fragility of the Zvezda module itself, caused by stress fractures. It is still used for Progress dockings, and Progress is still used to raise the orbit of the station. There is a growing fear that the module itself could crack catastrophically during those operations.
A Progress launch is scheduled for next week. The Russians quit docking Progress and Soyuz modules directly on Zvezda’s aft port for a few years now. They have been docking to the Poisk module that is at the zenith port on Zvezda, and the Prichall module, which is connected to the Nauka module, which is connected to the nadir port of Zvezda.
” The Russians quit docking Progress and Soyuz modules directly on Zvezda’s aft port for a few years now.”
This is not correct. Progress needs to be attached to the aft port of the Service Module in order to reboost the station. Not coincidently, the Progress on mission ISS-89P is docked there now.
Thanks for the correction mkent, The site I have been looking at has the zenith and nadir dockings listed and updated, but has not updated the aft dockings for some time. I thought the Russians were pumping the propellant from the Progress spacecraft to Zvezda to use it’s engines to boost the orbit. I was wrong.