The International Space Station has been continuously occupied since November 2000. Credit: NASA
On June 5, 2026, NASA ordered five astronauts aboard the International Space Station (ISS) to shelter in place in a docked spacecraft and prepare to abandon ship. The cause was a long-standing but worsening air leak in the Russian part of the station.
An hour and a half later, the alert was lifted, allowing the crew to resume their work. But this episode reminds us that humanity’s most expensive science experiment – and a remarkable symbol of international cooperation – is showing its age.
The ISS was born out of the deterioration in relations between Washington and Moscow in the immediate aftermath of the Cold War. In the early 1990s, the countries decided to merge the separate space station projects that each country was working on.
The air leak in an older part of the ISS, known as the Zvezda PRK Transfer Tunnel, is a dose of engineering reality. This is caused by fine cracks in the structure of the tunnel, which provides access to the spacecraft docking port. There is no permanent solution and the cracks have already been patched using sealant.
NASA and Russia’s space agency Roscosmos dispute the severity of the problem. Roscosmos says the slow leak poses no threat, while the US space agency views it as an increased security risk. Not only is the structure under stress, but also the fabric of the agreement that keeps the ISS running.
In 2024, ISS Advisory Committee Chairman Bob Cabana said: “NASA has expressed concerns about the structural integrity of the PRK and the possibility of a catastrophic failure.”
As early as June 2026, new cracks appeared and the leakage rate increased. This prompted Roscosmos to propose a solution. According to a report in technology magazine Ars Technica, the Russians wanted to repair the hull using a drill.
NASA balked at the plan and Roscosmos later abandoned it, only to come up with a new plan. Under this second proposal, Russian astronauts would use a saw to remove load-bearing brackets in the tunnel.
When NASA heard this, agency officials ordered the five astronauts to shelter in SpaceX’s Crew Dragon capsule, ready to separate from the space station if an accident occurred.
Roscosmos also abandoned another plan, forcing NASA to call the astronauts back to the ship. Since the incident, Roscosmos has told NASA that it will close the PRK tunnel from the rest of the station, in order to draw a line under the problem.
a professional future
The ISS was never intended to be immortal. The plan was always to let the competitive commercial market take over privately built space stations. After this, NASA will send its astronauts to these new orbiting outposts, where private astronauts will also come frequently.
West Haven-1 is currently at the forefront of the race to reach low Earth orbit. It has about one eighth of the ISS’s living space and is designed for short stays of up to a month. It also relies heavily on docked SpaceX capsules for air and power. Haven-1 is a test bed, not a replacement for similar ones, and despite optimistic estimates of launch in 2026, it is now unlikely to fly before 2027.
Stations that could completely replace the ISS are even further away. Vaast’s modular Haven-2 aims to have its first module built in 2028 and be completed in 2032, the same year the ISS is now scheduled to leave service. This leaves no scope for regular delays in these programmes.
Two other companies, Axiom and Starlab Space, are also planning larger orbiting outposts. However, these are still in development, and Axiom has recently faced financial troubles.
The problem is that companies and the people who finance them are unwilling to step up. The extent to which ISS replacements will be market-led has been consistently overstated. Government space agencies are going to be the main tenants and payers, making this a commercial sector that the US is paying to bring into existence.
Faced with less-than-ideal private sector involvement and delays, US lawmakers have extended the life of the ISS. NASA was to operate the ISS until 2030. Recent legislation, which is awaiting approval, would delay decommissioning the ISS until 2032.
This is, in part, a response to NASA’s stalled procurement of commercial replacements for the ISS. Recent legislation recognizes this, linking any retirement of the ISS to being ready for a replacement and warning against a scenario where China is the only country with a continuing human presence in low Earth orbit.
how does iss end
And as the ISS nears the end of its life, there’s a messy legal landscape looming. To close the outpost, NASA will push the 420-tonne space station into Earth’s atmosphere using a customized SpaceX Dragon vehicle – at a cost of about US$840 million (£638 million).
This controlled re-entry will take place at Point Nemo, the farthest part of the Pacific Ocean. This significantly reduces the risk of debris landing in populated areas.
Yet the space station would be the largest orbiting object ever sent through the atmosphere and pieces as large as a small family car could survive the descent. Who will be responsible if something goes wrong?
Under the United Nations Liability Convention, a 1972 treaty, the nation that launches a space object is liable for any damage it causes. But the ISS was built from modules launched by more than one country, primarily the US and Russia.
Where two or more States launch together they are jointly and severally liable, the latter term meaning that only one of them can be held responsible for the whole of the loss. ISS partners include the United States, Russia, Japan, Canada, and participating member states of the European Space Agency.
If a piece of the station falls where it shouldn’t, causing damage, liability is absolute – there is no need to prove fault. If the de-orbiting process causes damage to a satellite in orbit, liability depends on fault. Proving fault in a complex scenario such as ISS decommissioning can be extremely difficult.
The ISS air leak is a reminder that space stations will require constant maintenance. Private companies will not be able to escape the “sell and forget” mentality when launching their outposts.
With no obvious paying customers other than space agencies, investors are reluctant to rush into expensive commitments. Extending the life of the ISS provides a temporary patch, but it does not address the fundamental problem of who pays to replace it.
Christopher Newman, Professor of Space Law and Policy, Northumbria University, Newcastle
This article is republished from The Conversation under a Creative Commons license. Read the original article.
