Tag: ISS

Inspector General: The state of NASA’s spacesuits on ISS is becoming critical

1:28 pm

NASA's failed spacesuit
NASA’s failed Moon spacesuits

A new NASA inspector report issued today [pdf] has found that the single contractor NASA uses to maintain the spacesuits on ISS, Collins Aerospace, has increasingly been unable to do the job, and NASA has no alternative contractor to turn to. From the report’s executive summary:

We previously reported on NASA’s spacesuit management in 2017 and 2021, finding that the Agency faced a wide array of risks to sustaining the EMUs [the spacesuits], including design inadequacies, health risks, and low inventories of spacesuit life support systems, ultimately leading to NASA’s efforts to design and develop next-generation suits to replace the existing EMUs. Specifically, the EMU design flaws have increased the chance of and led to unexpected water in helmets, thermal regulation malfunctions, and astronaut injuries. Given that spacesuits are necessary to meet future ISS maintenance needs until its planned decommissioning in 2030, it is critical that NASA effectively manages the contract performance and subsequent safety risks associated with ESOC [the contract with Collins].

…Until the ISS’s planned decommission at the end of the decade, NASA will continue to require spacewalking capabilities to perform upgrades and corrective and preventative maintenance to the Station. However, Collins’ performance on ESOC increases programmatic risks to NASA as it attempts to conduct safe spacewalks outside the ISS and maintain critical EMU life support component inventories. The contractor is experiencing considerable schedule delays, cost overruns, and quality issues that significantly increase the risk to maintaining NASA’s spacewalking capability.

Collins was awarded this five-year cost-plus maintenance contract in 2010 for $324 million. Since then NASA has been repeatedly extending it, so that it now runs through 2027 and has funneled $1.4 billion into Collins’ bank account. Yet Collins has repeatedly failed to deliver necessary repair parts, even as there have been more frequent problems on ISS, including several cases where spacewalks had to be aborted because an astronaut’s life was in danger. Here are just a few examples cited in the report:
» Read more

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NASA cancels Sierra Space’s contract for Dream Chaser cargo missions to ISS

8:01 am

Tenacity grounded in a warehouse
Tenacity grounded in a warehouse, with the
Shooting Star small cargo capsule attached to
its aft port.

NASA today announced it has modified its fixed-price cargo contract with Sierra Space, canceling the planned seven cargo missions as well as a demo docking mission, replacing this with one test flight that will simply go into orbit and then return to Earth.

After a thorough evaluation, NASA and Sierra Space have mutually agreed to modify the contract as the company determined Dream Chaser development is best served by a free flight demonstration, targeted in late 2026. Sierra Space will continue providing insight to NASA into the development of Dream Chaser, including through the flight demonstration. NASA will provide minimal support through the remainder of the development and the flight demonstration. As part of the modification, NASA is no longer obligated for a specific number of resupply missions, however, the agency may order Dream Chaser resupply flights to the space station from Sierra Space following a successful free flight as part of its current contract.

The first launch of Tenacity, the only Dream Chaser so far constructed, has been repeatedly delayed for the past two years, with no explanation from either the company or NASA. Those delays started in 2023 as engineers began the final ground testing before launch, so though we do not know what the issue is it is likely that testing found something fundamentally wrong with the spacecraft that Sierra could not afford to fix.

According to Sierra’s own press release, the company will target a late 2026 launch for that free flyer mission. The company still hopes that mission will make further flights possible, either purchased by NASA or by others wishing to use Tenacity for in-orbit manufacturing, something it first proposed last year.

In the past two years, Sierra has shifted its focus away from commercial manned space and more towards winning military defense contracts. Part of that decision might have come from the problems with Dream Chaser. The decision might have also been fueled by the company’s generally unsatisfactory experience working with Blue Origin on their proposed Orbital Reef space station. While Sierra committed cash to develop and test its LIFE inflatable module, including a full scale prototype, Blue Origin appeared to do nothing at all. As early as September 2023 there were rumors the partnership was falling apart.

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ISS research suggests weightlessness accelerates aging in stem cells

8:58 am

According to a study that flew stem cells on four separate missions to ISS ranging in length from 32 to 45 days, weightlessness appears to age stem cells significantly.

Researchers from University of California San Diego Sanford Stem Cell Institute have discovered that spaceflight accelerates the aging of human hematopoietic stem and progenitor cells (HSPCs), which are vital for blood and immune system health. In a study published in Cell Stem Cell, the team used automated artificial intelligence (AI)-driven stem cell-tracking nanobioreactor systems in four SpaceX Commercial Resupply Services missions to the International Space Station (ISS) to track stem cell changes in real time. The findings show that the cells lost some of their ability to make healthy new cells, became more prone to DNA damage and showed signs of faster aging at the ends of their chromosomes after spaceflight — all signs of accelerated aging.

Upon return to Earth the study also found the cells recovered somewhat.

You can read the peer-reviewed paper here.

In a sense, this study confirms what numerous other research has found, that weightlessness mimics the conditions of old age, and causes the same physical decline seen in the elderly. It also shows that much of that damage in weightlessness is transient, recovering upon return to Earth.

This research once again highlights the imperative need to study the impact on various levels of artificial gravity on the human body. Will producing a 10% g environment — using centrifugal force — mitigate these negative impacts? Or will we have to simulate a full 1 g environment? Or something in between?

The first option is much easier in terms of engineering. The last will be complex and take time to develop.

At the moment almost no research has been done in this area. And it needs to happen soon, if people intend to go to Mars in the near future. Such journeys, six months minimum in weightlessness, are likely to leave the passengers somewhat debilitated upon arrival, no matter how much they exercise along the way. And being debilitated is not a good condition for a pioneer trying to build a new civilization on an alien world.

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NASA and Northrop Grumman work out rendezvous plan to get Cygnus to ISS

11:08 pm

UPDATE: The plan worked and Cygnus is safely berthed at ISS.

According to a press release tonight, NASA and Northrop Grumman have figured out a new rendezvous plan to get Cygnus to ISS after its previous engine burns yesterday cut off prematurely and left it in the wrong orbit.

NASA and Northrop Grumman are targeting the safe arrival of the company’s Cygnus XL at approximately 7:18 a.m. EDT Thursday, Sept. 18, to the International Space Station. The Cygnus XL now will conduct a series of burns to bring the spacecraft to the space station for its robotic capture and installation.

NASA astronaut Jonny Kim is scheduled to capture Cygnus XL using the station’s Canadarm2 robotic arm with backup support from NASA astronaut Zena Cardman. After capture, the spacecraft will be installed on the Unity module’s Earth-facing port and will remain at the space station until March 2026.

The release also added this detail about why that engine burn ended too soon:

Data shared by the spacecraft confirmed that Cygnus XL operated as intended during two planned maneuvers when an early warning system initiated a shutdown command and ended the main engine burn because of a conservative safeguard in the software settings.

Apparently this cause has reassured them that the engine is in good shape for the final rendezvous burns.

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Premature engine cutoff forces postponement of Cygnus berthing to ISS

11:16 pm

During the second of two engine burns today, designed to raise the orbit of Northrop Grumman’s Cygnus freighter to match ISS’s, the burn ended prematurely, placing the capsule in the wrong orbit.

Early Tuesday morning, Cygnus XL’s main engine stopped earlier than planned during two burns designed to raise the orbit of the spacecraft for rendezvous with the space station, where it will deliver 11,000 pounds of scientific investigations and cargo to the orbiting laboratory for NASA. All other Cygnus XL systems are performing normally.

The berthing, using one of the robot arms on ISS, had been planned for early tomorrow, Wednesday, but will not occur until both NASA and Northrop Grumman engineers have analyzed the issues and come up with “an alternate burn plan”.

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Progress docks safely with Zvezda module at ISS

9:24 am

ISS as of today
ISS as of today. Click for original.

In what is increasingly a worrisome procedure, Russia’s just launched Progress freighter successfully docked with the aft port of the Zvezda module at ISS this past weekend, bringing with it more than 5,000 pounds of supplies and research equipment.

The image to the right, annotated additionally by me, shows the present configuration of spacecraft at ISS. The concerns center on the stress fractures that have been found in the Zvezda hull, fractures that have caused the air leak on ISS and are believed attributable to the many dockings to the module since its launch in the late ’90s, as well as the module’s age. It was first built in the late ’80s, making it almost four decades old.

For recent dockings, NASA now closes the hatch between the Russian and American halves of the stations, just in case Zvezda experiences a catastrophic failure. The Russians seem less concerned, but nonetheless they also take extra care during dockings. It is my understanding their astronauts prepare their Soyuz capsule as a lifeboat and immediately escape during these operations.

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SpaceX launches Northrop Grumman’s Cygnus freighter to ISS

8:13 pm

SpaceX today successfully launched Northrop Grumman’s Cygnus freighter with more than five tons of cargo, its Falcon 9 rocket lifting off from Cape Canaveral in Florida.

The first stage completed its fourth flight, landing back at Cape Canaveral. The two fairing halves completed their 3rd and 6th flights respectively. Cygnus is expected to be berthed to ISS using the robot arm on September 24, 2025. This is also the first flight of the stretched version of Cygnus, capable of carrying more cargo.

The leaders in the 2025 launch race:

118 SpaceX
53 China
13 Russia
12 Rocket Lab

SpaceX now leads the rest of the world in successful launches, 118 to 92. China also had its own launch scheduled for this evening, but no information about it has yet been released.

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Russia launches Progress to ISS

9:24 am

Russia today successfully launched a Progress freighter to ISS, its Soyuz-2 rocket lifting off from the Baikonur spaceport in Kazakhstan.

The freighter will dock with the aft port of the Zvezda module in two days. When it does so, expect NASA to require its astronauts to close the hatch between the American and Russia parts of ISS. The agency has real concerns about the stress fractures in Zvezda’s hull that are the cause of the station’s air leaks, and fears it could at some point fail catastrophically during a docking. The odds of this happening are small, but they are larger than they should be.

The leaders in the 2025 launch race:

115 SpaceX
53 China
12 Rocket Lab
12 Russia

SpaceX still leads the rest of the world in successful launches, 115 to 91. The company has another launch scheduled for later today.

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Cargo Dragon completes test burn to raise ISS’s orbit

8:51 am

The cargo Dragon that docked with ISS in late August successfully completed yesterday an engine burn lasting more than five minutes to see if it could raise ISS’s orbit.

On Wednesday, Sept. 3, SpaceX’s Dragon completed an initial burn to test the spacecraft’s new capability to help maintain the altitude of the International Space Station. Two Draco engines located in the trunk of Dragon, which contains an independent propellant system, were used to adjust the space station’s orbit through a maneuver lasting five minutes, three seconds. The initial test burn increased the station’s altitude by around one mile at perigee, or low point of station’s orbit, leaving the station in an orbit of 260.9 x 256.3 miles. The new boost kit in Dragon will help sustain the orbiting lab’s altitude through a series of longer burns planned periodically throughout the fall of 2025.

The Dragon will remain docked with ISS until December. It is expected it will do additional test burns during that time.

NASA wishes to get this capability from its own spacecraft so as to no longer have to rely entirely on the Russians, who have traditionally done these orbital adjustments using its Progress cargo freighters. SpaceX likely also wants to do these tests as an adjunct to its contract to build the de-orbit vehicle that will bring ISS down, after it is retired.

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Texas brewery tries brewing beer and growing barley on ISS

1:19 pm

A Texas brewery dubbed Starbase Brewing (no connection to SpaceX) has just completed an experiment on ISS where it tried to brew beer in weightlessness as well as grow barley in simulated Martian soil.

Starbase Brewing — unrelated to Elon Musk’s space company or its South Texas city of Starbase — sent its MicroBrew-1 and OASIS experiments to the International Space Station aboard a SpaceX mission Aug. 1. They came back aboard a SpaceX Dragon spacecraft that splashed down eight days later off the coast of California.

…OASIS, short for “Optimizing Agriculture in Simulated Interplanetary Soils,” is the result of a partnership between the beer maker, Texas A&M AgriLife and Jaguar Space, a Colorado bioastronautics firm. According to Argroves, who launched the company in 2020, the goal was to grow barley in a mixture of Martian soil simulant with a byproduct of beermaking called Brewer’s Spent Grain and microbes.

The MicroBrew-1 experiment attempted to ferment beer, mixing “eight containers loaded with half wort — the sugary liquid extracted from malted grains — and half yeast.”

The company is far from manufacturing space-grown beer, but its founder seems focused on being the first brewery selling beer on Mars.

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Endurance capsule splashes down safely, returning four astronauts from ISS

8:56 am

SpaceX’s Endurance Dragon capsule successfully splashed down off the coast of California this morning, returning four astronauts from ISS after a five month mission.

I have embedded the live stream below. As of posting the capsule was about to be lifted from the water and placed in its nest on the recovery ship.

Once again it is important to note that this recovery is being done entirely by a private company and its employees. Once Endurance undocked from ISS NASA had no part to play. It purchased the ride from SpaceX, and SpaceX is providing the service.
» Read more

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Russia desperately lobbies the U.S. to continue and expand its space partnership

10:06 am

Roscosmos: a paper tiger
Roscosmos: a paper tiger

A string of short articles in Russia’s state-run press today, describing the meetings between the head of Roscosmos, Dmitry Bakanov, and interim NASA administrator Sean Duffy, suggest strongly that Russia is desperate to link itself with someone in order to continue its generally bankrupt space program.

Bakanov is making his first visit to the U.S. He and Duffy are also conducting the first face-to-face talks by the heads of their respective agencies in eight years. While the U.S. press has been entirely uninterested in these discussions, mostly because it knows little of substance will come of them other than an agreement to maintain the partnership at ISS through its planned retirement in 2030, the reaction by Russia’s press has been remarkably fawning, repeatedly proposing the U.S. and Russia expand their partnership beyond ISS:

Very clearly, Bakanov was trying to convince Duffy to consider a greater partnership, whereby Roscosmos and NASA do other space projects together. He might have even been offering to join NASA’s Artemis program to explore the Moon.

It appears from the other Russian state-run reports, however, that Duffy’s response was diplomatic but unenthused by such a proposal. All he apparently agreed to was to continue the ISS partnership, until the station’s retirement.
» Read more

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Endeavour launched successfully, carrying four astronauts to ISS

9:03 am

SpaceX’s Endeavour Dragon capsule has been successfully placed in orbit carrying four astronauts to ISS, its Falcon 9 rocket lifting off from Kennedy in Florida.

This is Endeavour’s sixth flight. It will dock at ISS in the early hours tomorrow. The first stage completed third flight, landing back in Florida.

The leaders in the 2025 launch race:

96 SpaceX
41 China
10 Rocket Lab
9 Russia

SpaceX now leads the rest of the world in successful launches, 96 to 71.

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Russians: Air leak on ISS reduced but still on going

9:48 am

According to a report in Russia’s state-run press today, the repairs to the air leak in the Russian Zvezda module on ISS have reduced the rate of air lose significantly, but have failed to eliminate it.

Long-term observations have shown that the leak in the interstitial chamber of the Zvezda module of the International Space Station, which was reported to have been fixed in June, is still ongoing, though its rate has slowed significantly, Roscosmos Executive Director of Manned Space Programs, special presidential envoy for international space cooperation Sergey Krikalyov said.

“The leak is ongoing. We continue our efforts to find and fix it, with the recent repairs having seriously reduced the rate of air leakage. For some time we even thought that we had found the last crack and sealed it, though long-term observations have shown that it (air loss – TASS) continues,” he told a press conference ahead of the launch of the Crew Dragon Endeavour spacecraft carrying the Crew-11 mission crew.

Even if Russia succeeds eventually in sealing the leak entirely, this does not solve a more fundamental problem, the existence of stress fractures in the hull of Zvezda that have caused the leaks. That module, built in the 1990s and the second oldest module on ISS, remains at serious risk of catastrophic failure due to these fractures. That the leak has not yet been sealed suggests that new cracks are steadily forming even as Russian astronauts patch older cracks.

Though they do not say so, officials at both Roscosmos, NASA, and their partners in Europe and Japan are all praying that the station can last until 2030, when they plan to retire and de-orbit it. They all know however that there is a great risk that Zvezda will not cooperate, and cause an unplanned shut down much earlier.

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Update on eye research at ISS

10:03 am

Link here. The NASA update provides a nice overview of the research, beginning with this overview:

When astronauts began spending six months and more aboard the International Space Station, they started to notice changes in their vision. For example, many found that, as their mission progressed, they needed stronger reading glasses. Researchers studying this phenomenon identified swelling in the optic disc, which is where the optic nerve enters the retina, and flattening of the eye shape. These symptoms became known as Space-Associated Neuro-Ocular Syndrome (SANS).

The research suspects the changes are due to the fluid shifts in the body that take place due to weightlessness, with blood shifting from the legs to the head. Various projects have studied a number of solutions, including wearing leg cuffs, administering vitamin B, and possibly using centrifuge-created artificial gravity to mitigate the condition. The problem has also generated new work in developing better equipment for to studying the eye, including improved imaging and techniques for measuring the eye’s stiffness.

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Axiom’s ticket price for India’s astronaut on Ax-4 mission: $59 million

10:38 am

According to reports today in the India press, the price Axiom charged India’s space agency ISRO for training and then flying its astronaut on the just completed Ax-4 two-week mission to ISS was $59 million.

The expenditure by ISRO includes cost of [Shubhanshu] Shukla’s training for the mission as well as that of a seat on SpaceX’s Dragon spacecraft for the 20-day trip that launched Shukla, and three others — Peggy Whitson from the US, Slawosz Uznanski-Wisniewski of Poland and Tibor Kapu of Hungary — to space.

Earlier reports had suggested Axiom was charging $70 million per ticket. If the $59 million is accurate and applies to the charges Poland and Hungary paid, then Axiom’s revenue for the flight was $177 million. From that it would have to pay SpaceX (for the launch and the use of its Grace capsule) and NASA (for the use of ISS). Based on past history, SpaceX likely charged around $70 million for the launch. The cost for using Grace is unknown. NASA’s fees for a two-week visit to ISS were probably around $10 million plus.

My guess, based on this very limited information, is that Axiom made some profit from the flight, ranging from $20 to $50 million.

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Axiom’s commercial manned mission to ISS splashes down safely

8:56 am

Axiom’s fourth commercial manned mission to ISS successfully splashed down off the coast of California early this morning, returning its astronaut commander, employed by Axiom, and three government passengers from India, Poland, and Hungary after spending two weeks at the space station and eighteen days total in space.

For all three nations this was their second manned flight, and the first in more than four decades. All three had previously flown astronauts on Soviet era Soyuz missions, with Poland and Hungary’s astronauts visiting the Salyut 6 station in 1978 and 1980 respectively, and India’s astronaut visiting the Salyut 7 station in 1984.

The mission also marked the inaugural flight of SpaceX’s new Grace reusable manned Dragon capsule, the fifth such spacecraft in its fleet. SpaceX’s fleet is now larger that NASA’s space shuttle fleet ever was.

If you watch the live stream at the link, it is once again important to note that everyone you see on the screen, except for these three government astronauts, are employees of SpaceX or Axiom. There is no government involvement at all in the splash down procedure. It is entirely commercial and private affair.

In other words, who needs NASA for spaceflight? It clearly is not required.

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Dragon capsule undocks from ISS carrying four Axiom’s passengers

8:47 am

After spending 18 days in space, 14 on ISS, the Dragon capsule early this morning undocked from ISS with a splashdown scheduled for early tomorrow.

The mission was financed by the space station company Axiom, and was commanded by former NASA astronaut Peggy Whitson, now employed by Axiom as a professional astronaut. The three paying passengers were all government astronauts from India, Poland, and Hungary.

The capsule, dubbed Grace, is the newest addition to SpaceX’s fleet of five manned reusable capsules, flying on its first mission.

Splashdown is scheduled for the wee hours of July 15th tomorrow off the coast of California. The live stream can be found here.

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Russia launches Progress freighter to ISS

1:04 pm

Russia today (July 4th in Kazakhstan) successfully launched a new Progress freighter to ISS, its Soyuz-2 rocket lifting off from the Baikonur spaceport in Kazakhstan.

The freighter will dock to ISS in two days, bringing with it almost three tons of cargo and more than a half done of hardware and equipment. Expect NASA to order its astronauts to shut the hatch between the American and Russian sections of ISS due its fear that a docking to the Zvezda module could cause a catastrophic failure because of the stress fractures in that module’s hull. That docking will however not be directly to Zvezda, but to the Poisk module that is itself docked to Zvezda.

The lower stages and strap-on boosters crashed inside Kazakhstan in the normal drop zones that Russia has used for decades.

The leaders in the 2025 launch race:

84 SpaceX
36 China
10 Rocket Lab
8 Russia

SpaceX still leads the rest of the world in successful launches, 84 to 63.

Russia’s launch pace this year is its lowest pace in decades. At this rate Russia might only get about 15-17 launches off in 2025, a count more comparable to what it did in the very early 1960s. This decline can be directly linked to the Russian invasion of the Ukraine. That invasion caused Russia to lose billions in contracts in the international launch market. And it continues to prevent Russia from winning any new international contracts as well. Except for its government launches (which are limited due to government cash shortages), the only other missions Russia flies are those to ISS, and those number about four per year.

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SpaceX launches Axiom’s fourth commercial manned mission to ISS

8:45 am

SpaceX last night successfully launched Axiom’s fourth commercial manned mission to ISS, dubbed Ax-4, its Falcon 9 rocket lifting off from the Kennedy Space Center in Florida.

The first stage completed its second flight, landing back at Cape Canaveral. The Dragon capsule, the newest and fifth ship in SpaceX’s fleet of manned capsule, was dubbed “Grace,” as announced by Axiom mission commander and former NASA astronaut Peggy Whitson. The three paying passengers are government astronauts from India, Hungary, and Poland.

The capsule will dock with ISS tomorrow (Thursday) at 7 am (Eastern), where it and its crew will spend about one to two weeks before returning to Earth.

The leaders in the 2025 launch race:

79 SpaceX
35 China
8 Rocket Lab
7 Russia

SpaceX now leads the rest of the world in successful launches, 79 to 58.

The overall lack of excitement about this manned space mission speaks directly to how successful SpaceX has become as a private commercial rocket company. Its rockets and capsules work routinely well, with almost no problems, making these manned space missions seem as boring as an airline trip from New York to Washington.

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NASA sets another new date for Axiom’s Ax-4 commercial manned mission to ISS

9:21 am

NASA today announced a new launch date of June 25, 2025 for Axiom’s Ax-4 commercial manned mission to ISS carrying a three passengers from India, Poland, and Hungary respectively and commanded by former NASA astronaut Peggy Whitson (now working for Axiom).

As with previous announcements, the information provided was sparse:

NASA, Axiom Space, and SpaceX are targeting 2:31 a.m. EDT, Wednesday, June 25, for launch of the fourth private astronaut mission to the International Space Station, Axiom Mission 4.

The mission will lift off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. The crew will travel to the orbiting laboratory on a new SpaceX Dragon spacecraft after launching on the company’s Falcon 9 rocket. The targeted docking time is approximately 7 a.m. Thursday, June 26. NASA will provide more details and its coverage information shortly.

The launch had previously been delayed several times because NASA and Russia wanted to first assess the repair work on the leaks in the Russian Zvezda module before allowing another docking at the station. No information however has been released so far detailing that assessment. Though there have been indications that the loss of air in ISS was stopped by the repair, neither NASA nor Roscosmos have provided any specific data.

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NASA delays Axiom manned mission again

9:11 am

Without providing any specific details, NASA today announced that it has once again scrubbed the June 22, 2025 launch of Axiom’s Ax-4 manned mission to ISS as it assesses the Russian repairs to the air leaks in the Russian Zvezda module.

The space agency needs additional time to continue evaluating International Space Station operations after recent repair work in the aft (back) most segment of the orbital laboratory’s Zvezda service module. Because of the space station’s interconnected and interdependent systems, NASA wants to ensure the station is ready for additional crew members, and the agency is taking the time necessary to review data.

No new launch date has been set. Because the agency provides so little specific information, we don’t know if the air leak repairs are working, are failing, or have indicated even more serious problems that make any station docking a greater risk. Almost certainly, this latter fear is unfounded and the repairs have succeeded in stopping or slowing the loss of air, but the paucity of information from NASA allows for wild speculations. It would be better if the agency told us what it has so far learned, and exactly why that knowledge requires it to extend the data-gathering time period.

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NASA/Axiom announce another four-day launch delay for Axiom’s fourth manned mission

8:55 am

NASA and Axiom today announced that they have rescheduled the launch of Axiom’s fourth manned mission to ISS, dubbed Ax-4, to June 22, 2025 in order to give Russian and American engineers more time to assess the leak repairs in the station’s Russian Zvezda module.

The press announcement provided little information, simply stating that:

The change in a targeted launch date provides NASA time to continue evaluating space station operations after recent repair work in the aft (back) most segment of the International Space Station’s Zvezda service module.

It would be nice if the agency would release some actual data. Earlier reports had suggested that the repairs had completely sealed the leaks and that the station was no longer losing air. The vagueness of today’s report suggests that the repairs might not have been as successful as hoped. It could also be engineers simply want more data for a longer period to prove the repairs have worked.

The lack of detailed information causes unnecessary speculation.

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Axiom manned flight to ISS rescheduled; NASA attempts to clarify ISS leak situation

9:26 am

In a NASA update today, it announced a new launch date of June 19, 2025 for Axiom’s fourth manned flight to ISS while also attempting to clarify ISS leak situation that caused this last and more extended delay.

On June 12, NASA and Axiom Space delayed the mission as the agency continued to work with Roscosmos to understand the most recent repair efforts to seal small leaks. The leaks, located in the aft (back) most segment of the International Space Station’s Zvezda service module, have been monitored by flight controllers for the past few years.

Following the most-recent repair, pressure in the transfer tunnel has been stable. Previously, pressure in this area would have dropped. This could indicate the small leaks have been sealed. Teams are also considering the stable pressure could be the result of a small amount of air flowing into the transfer tunnel across the hatch seal from the main part of space station. By changing pressure in the transfer tunnel and monitoring over time, teams are evaluating the condition of the transfer tunnel and the hatch seal between the space station and the back of Zvezda.

It appears, though NASA doesn’t say so directly, that the Russians did not wish to change the situation at ISS with another docking — even if it was a docking on the American half of the station — while it was evaluating these leak repairs. It now appears they have gotten enough data to allow NASA to set a new launch date later this week.

If the repairs have managed to stop the leaks this is excellent news. At the same time, it doesn’t reduce the risks of a catastrophic failure of Zvezda, since the existence of these numerous stress fractures in its hull suggest a chronic long term failure that can only worsen with time.

The sudden delay of Axiom’s AX-4 last week also indicates poor coordination between NASA and Roscosmos. It was as if NASA had no idea the repair work was occurring, either because it wasn’t paying attention to what the Russians were doing or because the Russians had kept this work secret until it was completed. In either case, this is not how such a partnership should operate.

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Axiom manned mission delayed further because of new Zvezda leaks on ISS

8:58 am

Figure 3 from September Inspector General report
Figure 3 from September Inspector General report, showing Zvezda’s location on ISS.

According to a press update today by NASA, the launch of the commercial Ax-4 manned mission to ISS has been further delayed due to work by the Russians attempting to seal new leaks in the station’s Zvezda module.

NASA and Axiom Space are postponing the launch of Axiom Mission 4 to the International Space Station. As part of an ongoing investigation, NASA is working with Roscosmos to understand a new pressure signature, after the recent post-repair effort in the aft most segment of the International Space Station’s Zvezda service module.

Cosmonauts aboard the space station recently performed inspections of the pressurized module’s interior surfaces, sealed some additional areas of interest, and measured the current leak rate. Following this effort, the segment now is holding pressure.

In other words, the Russians had recently detected an increase in leakage in the module, identified several more cracks inside Zvezda, and have been working to seal them.

The graphic above comes from a 2024 NASA inspector general report, which at that time noted a significant increase in the leak rate in 2024 (see the data in the lower right). Since then it has been NASA policy to close the hatch that connects the American and Russian sections of the station whenever anything docks with Zvezda, due to risk that the docking could cause the module to fail entirely.

Zvezda is one of the oldest modules on ISS, built in the late 1980s and launched in 2000. It is believed the leaks are due to stress fractures in its hull due to the many dockings and undockings that have occurred at its aft docking port.

If the NASA press release can be believed, the situation is under control and the repairs have been successful. If so, expect the Axiom mission to be rescheduled shortly.

If not, we could be witnessing the beginning of the end of ISS, five years earlier than planned by bureaucrats in Washington and Moscow.

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Axiom’s fourth commercial manned mission scrubbed due to leak

8:04 pm

Axiom and SpaceX have scrubbed the launch tomorrow of Axiom’s fourth commercial manned mission to ISS due to an oxygen leak detected during the standard prelaunch static fire test.

NASA, Axiom Space, and SpaceX are standing down from the launch opportunity on Wednesday, June 11, of Axiom Mission 4 to the International Space Station to allow additional time for SpaceX teams to repair a liquid oxygen leak identified during post-static fire Falcon 9 rocket inspections. A new launch date for the fourth private astronaut mission will be provided once repair work is complete, pending range availability.

There a number of launches already scheduled for Florida in the next few days, so it could be that the launch of Ax-4 could be delayed by more than a few days.

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Axiom charges $70 million per ticket to fly to ISS

9:08 am

Axiom's new module assembly sequence
Axiom’s assembly sequence for its planned station, initially attached to ISS but subsequently detached

According to this article today about Axiom’s tourist flights to ISS, the company now charges $70 million per ticket, which means that for the AX-4 flight scheduled for launch tomorrow, the revenues from India, Poland, and Hungary total about $210 million.

That money of course doesn’t all end up in Axiom’s pockets. It has to pay SpaceX for the launch and use of the Dragon capsule. It also has to pay NASA some recently imposed high fees to use its astronaut training facilities as well as lease time on ISS.

All told, I suspect Axiom’s profits for these flights is relatively small. The company however has other reasons to fly these missions. It is attempting to win NASA’s big space station construction contract, and these flights to ISS demonstrate the company’s ability to manage such operations while working with NASA. Of the other three space station projects competing for that contract, only Vast is planning to do the same.

This effort by these two companies is part of the reason I rank them first and second for winning that contract.

  • Haven-1, being built by Vast, with no NASA funds. The company is moving fast, with Haven-1 to launch and be occupied in 2026 for an estimated 30 days total. It hopes this actual hardware and manned mission will put it in the lead to win NASA’s phase 2 contract, from which it will build its much larger mult-module Haven-2 station..
  • Axiom, being built by Axiom, has launched three tourist flights to ISS, with a fourth scheduled for tomorrow, carrying passengers from India, Hungary, and Poland. Though there have been rumors it has cash flow issues, development of its first module has been proceeding more or less as planned.
  • Orbital Reef, being built by a consortium led by Blue Origin and Sierra Space. Overall, Blue Origin has built almost nothing, while Sierra Space has successfully tested its inflatable modules, including a full scale version, and appears ready to start building its module for launch.
  • Starlab, being built by a consortium led by Voyager Space, Airbus, and Northrop Grumman, with an extensive partnership agreement with the European Space Agency. It recently had its station design approved by NASA, but it has built nothing. This might change once it obtains several hundred million dollars from its initial public offering of stock.
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Axiom’s fourth commercial passenger flight to ISS delayed another two days

9:45 am

NASA, Axiom, and SpaceX yesterday announced that the launch of Axiom’s fourth commercial passenger flight to ISS, dubbed Ax-4, has been delayed two days to June 10, 2025.

NASA, Axiom Space, and SpaceX are targeting no earlier than 8:22 a.m. EDT on Tuesday, June 10, for launch of the fourth private astronaut mission to the International Space Station, Axiom Mission 4. This shift allows teams to account for predicted inclement weather during the SpaceX Falcon 9 rocket and Dragon spacecraft transport in addition to completing final processing of the spacecraft ahead of launch.

The Dragon capsule for this mission is new, and there had been delays in getting it built. Though weather is likely the biggest reason for this delay, it also sounds as if SpaceX has needed just a little bit of extra time to finalize the capsule’s construction.

The mission will fly one Axiom astronaut plus three passengers, each a government astronaut from India, Poland, and Hungary. It will spend about a week docked at ISS.

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Cargo Dragon splashes down and is recovered successfully

2:29 pm

A SpaceX cargo Dragon capsule was recovered successfully earlier today after it splashed down off the coast of California.

The spacecraft carried back to Earth about 6,700 pounds of supplies and scientific experiments designed to take advantage of the space station’s microgravity environment after undocking at 12:05 p.m., May 23, from the zenith port of the space station’s Harmony module.

Some of the scientific hardware and samples Dragon will return to Earth include MISSE-20 (Multipurpose International Space Station Experiment), which exposed various materials to space, including radiation shielding and detection materials, solar sails and reflective coatings, ceramic composites for reentry spacecraft studies, and resins for potential use in heat shields. Samples were retrieved on the exterior of the station and can improve knowledge of how these materials respond to ultraviolet radiation, atomic oxygen, charged particles, thermal cycling, and other factors.

Other cargo returned included a robot hand that tested its grasping and handling capabilities in weightlessness, as well as other experiments.

The capsule itself spent three months in orbit after launching at the end of April.

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