The Wrist That Broke
On a January morning in 2026, Chris Williams floated outside the International Space Station, tethered to nothing but protocol and a safety line, staring at a broken joint. The Canadarm2—17 metres of Canadian engineering that had assembled, maintained, and upgraded the orbital laboratory for more than two decades—could no longer bend its wrist . The joint had seized. Without it, the station's primary means of manipulating cargo spacecraft, moving equipment, and assisting spacewalkers was effectively paralysed.
Williams and his crewmate Jessica Meir would spend seven hours and twenty minutes outside the station that day, replacing the failed wrist mechanism in what amounted to surgery on a patient that could not be anaesthetised, only isolated . The repair was textbook—methodical, successful—but it arrived at the end of a month that had already forced NASA to postpone one spacewalk due to a medical concern with a crew member, and at the beginning of a year that would see Expedition 74 become a case study in operating a research laboratory when everything that can go wrong does .
This is the story of that expedition: not a catastrophe, but a slow accumulation of friction. A medical situation that remained unspecified but serious enough to cut short an entire crew rotation. A robotic arm that failed at precisely the wrong moment. A parade of cargo ships arriving and departing, each one a logistical puzzle. And through it all, a rotating cast of astronauts and cosmonauts who kept the station running, not because the plan held, but because the plan never does.
The Medical Question
The first crack in the schedule came in early January. NASA announced that it would postpone a planned spacewalk on 8 January 2026, citing 'a medical concern with a crew member on the International Space Station' . The agency provided no further details. Privacy protocols for astronauts are strict, and NASA's public affairs apparatus is calibrated to share only what it must.
What followed was unusual. Within days, NASA announced that it would return the four-member SpaceX Crew-11 mission to Earth earlier than originally planned . The crew undocked from the station at 5:20 p.m. EST on 13 January 2026, cutting short a mission that had been slated to run for months . Again, the agency declined to specify which crew member was affected, what the medical concern was, or whether the situation was urgent or merely prudent .
Multiple sources confirmed that the crew member in question was stable . NASA considered but ultimately did not pursue an emergency evacuation, opting instead for an early but controlled return . The decision suggests a medical situation serious enough to warrant curtailing a mission, but not so acute as to require the kind of high-risk, short-notice departure that the station's Soyuz and Crew Dragon capsules are designed to execute in extremis.
The opacity is deliberate. NASA does not publicly discuss crew medical issues unless the individuals involved choose to do so, a policy rooted in both legal privacy protections and the practicalities of recruitment. If every ailment or injury became a headline, fewer people would sign up for a job that already involves strapping oneself to a controlled explosion. But the silence also creates a vacuum, and vacuums fill with speculation. Was it a cardiac event? A psychological crisis? An infection that terrestrial antibiotics could manage but orbital medicine could not? The agency's refusal to clarify left those questions unanswered, and they remain so.
The Arm That Couldn't Reach
The Canadarm2 is not, strictly speaking, essential to life aboard the station. It does not generate oxygen, regulate temperature, or shield the crew from radiation. But it is essential to almost everything else . The 17-metre robotic manipulator, built by the Canadian Space Agency and delivered to the ISS in 2001, functions as the station's primary means of capturing visiting cargo spacecraft, repositioning modules, and moving equipment too large or unwieldy for astronauts to handle manually .
When its wrist joint failed, the timing could not have been worse. The station was in the middle of a logistics surge. The Cygnus XL cargo craft had recently been installed on the Unity module by Canadarm2, delivering tonnes of supplies, experiments, and hardware . Japan's HTV spacecraft was preparing for departure, another task requiring the arm's precision . And NASA had scheduled a pair of spacewalks in March to prepare the station's power channels for the installation of new roll-out solar arrays, work that would require the arm to position equipment and provide a stable platform for the astronauts .
The repair itself was a study in incremental risk. Williams and Meir began their spacewalk at 8:52 a.m. EDT, exiting the station into the kind of silence that only vacuum provides . The wrist joint—a complex assembly of motors, gears, and sensors encased in a housing designed to survive temperature swings of more than 250 degrees Celsius—had to be removed and replaced in situ. There was no bringing it inside for a workbench repair. The astronauts worked methodically, following procedures developed on the ground and rehearsed in the Neutral Buoyancy Laboratory, a massive pool in Houston where spacewalks are simulated in painstaking detail .
Seven hours and twenty minutes later, they re-entered the station. The arm was whole again . Within days, it was back to work, releasing the Cygnus XL spacecraft to end its cargo mission and manoeuvring Japan's HTV for departure . The repair had held. But it was a reminder of how fragile the station's operational capacity is, and how much depends on machines that were never designed to be serviced in space.
The Parade of Departures
Expedition 74 began officially on 7 December 2026, when outgoing commander Sergey Ryzhikov handed over control of the station to NASA astronaut Mike Fincke in a brief ceremony . Command changes aboard the ISS are low-key affairs—a handshake, a few words, a symbolic passing of authority—but they mark the rhythm of life in orbit. Every few months, a new expedition begins. Some are uneventful. This one was not.
The crew rotations came in waves. Soyuz MS-27 undocked from the station on 11 February 2026, carrying its crew back to Earth after a mission that had overlapped with the early days of Expedition 74 . Less than two weeks later, an unpiloted SpaceX Dragon spacecraft undocked from the forward-facing port of the Harmony module at 12:05 p.m. EST on 26 February, packed with scientific samples and hardware returning from orbit . By the time that Dragon splashed down, Fincke had already handed over command to Roscosmos cosmonaut Sergey Kud-Sverchkov, a transition that underscored the international and rotational nature of station leadership .
Each departure is a minor logistical triumph. Spacecraft must be loaded with precision: cargo manifests are planned months in advance, and every kilogramme matters. Samples must be packed in temperature-controlled containers. Hardware must be secured. Hatches must be sealed, leak-checked, and sealed again. The crew works to checklists that run to hundreds of pages, and every step is monitored from the ground. When the Roscosmos Progress 93 cargo spacecraft undocked on 17 April 2026, it marked the end of another supply mission, another cycle of delivery and disposal .
But the departures also meant upheaval. Crew-11's early return had disrupted the planned rotation schedule, and NASA was forced to adjust. The agency announced crew assignments for SpaceX Crew-12, including ESA astronaut Sophie Adenot and Roscosmos cosmonaut Andrey Fedyaev as mission specialists, part of the constant effort to maintain a multinational presence aboard the station . The ISS is a political project as much as a scientific one, and the choreography of who launches when, on whose rocket, and under whose flag is negotiated years in advance.
The Spacewalks That Couldn't Wait
By March, the station's power situation had become pressing. The ISS generates electricity through eight solar arrays, each the size of a tennis court, that convert sunlight into the kilowatts needed to keep the laboratory running. But the arrays degrade over time—radiation, micrometeorite impacts, and simple age all take their toll. NASA's solution is a programme of augmentation: new roll-out solar arrays, smaller but more efficient than the originals, designed to be installed over the existing panels and boost power output .
The work required preparation. On 18 March, Jessica Meir and Chris Williams began a spacewalk at 8:52 a.m. EDT to prepare the 2A power channel for the future installation of one of the new arrays . It was the first of a pair of planned extravehicular activities, part of a carefully sequenced effort to upgrade the station's electrical infrastructure without interrupting operations. The astronauts worked outside for hours, routing cables, installing brackets, and verifying connections. Every task had been rehearsed on the ground, but in orbit, the margin for error is narrower. A dropped tool becomes a piece of orbital debris. A torn glove can end a spacewalk.
The second spacewalk followed days later, another sortie to continue the installation work . Meanwhile, Russian cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev conducted their own extravehicular activity, completing a six-hour, five-minute spacewalk focused on science hardware and maintenance tasks on the Russian segment of the station . The dual-track nature of ISS operations—American and Russian crews working in parallel, sometimes in coordination, sometimes independently—is a legacy of the station's design and the geopolitical compromises that made it possible.
'The station is a machine, but it's also a negotiation. Every spacewalk, every cargo ship, every crew rotation is the result of agreements made years earlier, and adjusted constantly.'
The spacewalks were not without cost. Each one places wear on spacesuits that are themselves ageing pieces of equipment, some of them decades old. Each one exposes astronauts to radiation levels higher than those inside the station's shielded modules. And each one requires ground teams in Houston, Moscow, and elsewhere to monitor every moment, ready to troubleshoot or abort if something goes wrong. The fact that none of Expedition 74's spacewalks ended in disaster is not luck. It is the product of exhaustive planning, rigorous training, and a tolerance for risk that most people would find unacceptable.
The Cargo That Kept Coming
Amid the medical concerns and the repair work, the station's logistics pipeline never stopped. The Cygnus XL cargo craft arrived and was installed on the Unity module by Canadarm2, delivering supplies and experiments . Weeks later, after the arm had been repaired, it released the Cygnus to end its mission, sending the spacecraft to burn up in the atmosphere . Japan's HTV cargo vehicle followed a similar arc: arrival, berthing, unloading, and release, with Canadarm2 manoeuvring it through each stage .
The Progress 93 spacecraft, a Russian cargo vehicle, undocked on 17 April 2026, carrying trash and no-longer-needed equipment to a fiery end over the Pacific . The rhythm is relentless: every few weeks, a new cargo ship arrives. Every few weeks, an old one departs. The station consumes supplies—food, water, spare parts, scientific equipment—at a rate that requires constant replenishment. Without the cargo pipeline, the ISS would be uninhabitable within months.
But the pipeline is fragile. It depends on rockets that must launch on time, spacecraft that must dock without error, and robotic systems that must function flawlessly. When Canadarm2's wrist joint failed, it threatened to disrupt the entire sequence. The repair bought time, but it also highlighted a deeper problem: the ISS is ageing, and its systems are reaching the end of their design lives. NASA and its partners have committed to operating the station through at least 2030, but every year brings new challenges, new failures, new repairs.
The Expedition That Endured
Expedition 74 did not fail. The crew returned safely. The science continued. The station remained operational. But it was a near-run thing, a reminder that orbital operations exist on the edge of controlled chaos. A medical situation that could have become an emergency but didn't. A robotic arm that could have crippled logistics but was repaired in time. A series of spacewalks that went according to plan, mostly.
The ISS is often described as a triumph of international cooperation, and it is. But it is also a machine held together by constant improvisation, by crews who troubleshoot in real time and ground teams who rewrite procedures on the fly. Expedition 74 succeeded not because everything went right, but because when things went wrong, the people involved found ways to keep going.
Mike Fincke handed over command. Sergey Kud-Sverchkov took it. Crews rotated. Cargo ships came and went. Spacewalkers ventured outside and came back in. The station, as always, kept turning, a bright dot moving across the night sky, 400 kilometres up, crewed by people who have learned to expect the unexpected and respond with something that looks, from the ground, like calm.
It is not calm. It is competence under pressure, rehearsed a thousand times and executed when it matters. Expedition 74 was not the smoothest mission in the station's history, but it may have been one of the most instructive. It showed what happens when the plan breaks down and the backup plan has to be written on the spot. It showed that the ISS, 26 years into its operational life, is still flying—but only just, and only because the people aboard it and on the ground refuse to let it fall.