The desire for a permanent American space station predates the Apollo programme. Wernher von Braun had been advocating for an orbital station since the 1950s — his famous wheel-shaped design appeared on the cover of Collier’s magazine in 1952, seventeen years before Apollo 11. After Skylab demonstrated that humans could live and work in orbit for extended periods, NASA pressed persistently for a follow-on station. The Shuttle, when it finally flew in 1981, was supposed to be the logistics vehicle that made a permanent station possible. The station itself was always the next step.
On 25 January 1984, President Reagan made it official. In his State of the Union address, he directed NASA to develop a permanently crewed space station and to do it within a decade — a deadline that would prove as unrealistic as Kennedy’s had been audacious. The difference was that Kennedy’s programme had clear technical objectives, adequate funding, and unified direction. Freedom had none of these things.
What followed was nine years of institutional paralysis disguised as progress. The programme was structured across four NASA centres — Marshall, Johnson, Lewis, and Goddard — each responsible for a separate work package, each with its own contractors, its own priorities, and its own institutional momentum. The result was a design that grew in cost and complexity with each passing year while simultaneously shrinking in capability. In April 1987, the design Freedom’s creators described as a Dual Keel configuration — a grand structure of perpendicular trusses and pressurised modules — was found to cost at least $14.5 billion in 1984 dollars, triggering a congressional uproar that forced yet another redesign. By 1990, the design had collapsed under its own weight: it was 23% too heavy, over budget, too complicated to assemble, and provided 34% too little power for its users. Seven major redesigns in nine years, each one cutting capability while raising costs, had produced a programme that had spent $11 billion building almost nothing.
The name Freedom, given to the station by Reagan in June 1988, sat with increasing irony over a programme that seemed imprisoned by its own institutional architecture. Congressional patience was exhausted. The incoming Clinton administration was openly sceptical. And then, quite unexpectedly, the solution appeared — from the ruins of the programme Freedom had been designed to compete against.
The Last Soviet Citizen
To understand how the Soviet Union’s collapse saved the space station programme, you need to understand what was happening 400 kilometres above the Earth on 25 December 1991.
Sergei Krikalev had launched to Mir in May 1991 for what was supposed to be a five-month mission. He was a 33-year-old flight engineer, quiet, technically brilliant, the best manual pilot in the cosmonaut corps. He had been up there when the August coup attempt against Gorbachev failed. He had been up there when the Baltic states declared independence. He had been up there, in October, when his crewmates returned to Earth and couldn’t be replaced because Russia had sold the only available Soyuz seat to an Austrian cosmonaut for $7 million. He had been up there when Japan paid $12 million to send a television reporter. There was simply no money to send him a replacement. He stayed.
On Christmas Day 1991, Mikhail Gorbachev resigned and the Soviet Union ceased to exist. The flag above the Kremlin was lowered. The USSR stamp in Krikalev’s passport became, overnight, the identification of a country that no longer existed. His home city had been renamed: Leningrad was now St Petersburg, a place he had never lived. He circled the Earth watching continents drift past his porthole, unable to come home because the country that had sent him had disappeared.
He finally returned on 25 March 1992, after 311 days in space — twice his planned mission duration, a world record he had not sought. Four men helped him stand as he emerged from the Soyuz capsule, pale and unsteady, wearing a spacesuit with the letters USSR on the chest. He landed near Arkalyk, now in the newly independent Republic of Kazakhstan. He asked them to bring him honey. They threw a fur coat over his shoulders in the spring snow. A reporter asked him which of the changes had surprised him most — Gorbachev gone, Yeltsin in power, Leningrad become St Petersburg? He answered with complete literalness: “What surprises me most? That at first the Earth was dark, and now it’s white. Winter has come, and before it was summer. Now it’s beginning to bloom again. That’s the most impressive change you can see from space.”
Krikalev went straight back to training. Within a year he was in Houston, preparing to fly on a Space Shuttle. The first Russian to fly on an American spacecraft. The last Soviet citizen had become the first ambassador of a new relationship.
The Pivot
The strategic calculus that turned the Soviet Union’s collapse into the ISS’s salvation was, at its core, about nuclear weapons and their engineers. The post-Soviet Russian space programme was in existential crisis. Thousands of engineers and scientists who had built the world’s most capable rocket systems were going unpaid, or being paid in factory goods that couldn’t be exchanged for food. The same facilities that had built ICBMs were struggling to meet payroll. The geopolitical fear in Washington was explicit: if these people couldn’t find legitimate employment in Russia, they would find employment elsewhere — in Iran, in North Korea, in any state that wanted their knowledge and could pay for it. Keeping Russian aerospace engineers busy on cooperative space projects was cheaper and safer than any alternative.
NASA administrator Daniel Goldin and Russian Space Agency director Yuri Koptev signed cooperative agreements in October 1992. The Clinton administration, looking at a space station programme that had spent $11 billion and produced nothing flyable, saw the opportunity simultaneously: Russian experience in long-duration spaceflight, Russian hardware that actually worked, and Russian engineers who needed the work. In 1993 Clinton directed NASA to redesign Freedom one more time — this time incorporating Russian participation. The redesign produced a station that was genuinely new: larger, more capable, more sustainable, and crucially, buildable with the resources available.
The June 1993 vote was on the redesigned programme. It survived by one vote. By October, the merger with the Russian programme was formalised. Space Station Alpha — the name that briefly replaced Freedom, which some in the programme had taken to calling “Space Station Fred” in weary irony — eventually became the International Space Station.
The partnership faced immediate scepticism from both sides. American engineers worried about Russian reliability after years of Cold War secrecy. Russian engineers worried about subordinating their hard-won expertise to an American management structure. Congressional opponents raised the valid concern that integrating Russian hardware created a dependency on a geopolitically unreliable partner. All of these concerns would prove prescient at various points over the following three decades. None of them outweighed the alternative, which was no station at all.
The Shuttle-Mir Bridge
Before a single ISS module could be built, the two programmes needed to learn to work together. The Shuttle-Mir programme, running from 1994 to 1998, was the apprenticeship. Seven American astronauts spent extended periods aboard Mir — Shannon Lucid, Jerry Linenger, Michael Foale, and others — living on a Russian space station, learning the systems, learning the language, learning what it meant to trust your life to hardware built by former adversaries.
The experiences were not uniformly comfortable. Jerry Linenger’s stay in early 1997 included a serious fire when a solid-fuel oxygen generator — a Vika canister — caught fire and burned for fourteen minutes, filling the station with smoke and blocking access to one of the two Soyuz emergency return vehicles. The crew managed to extinguish it. Two months later an unmanned Progress cargo spacecraft, during a manual docking test, struck the Spektr module, puncturing its hull and causing a slow depressurisation that forced the crew to seal off the module permanently. Mir was losing pressure. The station had been held together, in the memorable phrase of one NASA official, “with baling wire, duct tape, and healthy doses of WD-40.” It survived both incidents. So did the partnership.
The experience was invaluable precisely because it was difficult. American engineers learned what worked and what didn’t about Russian station systems — not from documents but from lived experience. The trust that was built was not abstract diplomatic trust but the specific, personal trust of people who had shared dangerous situations and come through them together. When ISS assembly began, this foundation mattered enormously.
Building a City in Orbit
On 20 November 1998, a Proton-K rocket lifted off from Baikonur and placed Zarya into orbit. The name means Sunrise — chosen to symbolise a new era of international cooperation, or possibly chosen because its irony was too good to pass up, given that it had been built with mothballed hardware from a cancelled Soviet laser weapons programme. Zarya’s structure traced its lineage to the TKS spacecraft developed for the Salyut programme. It had been funded by $220 million in NASA contracts and built in Moscow by the Khrunichev factory — American money, Russian hardware, in orbit above both their countries simultaneously.
Two weeks later, Space Shuttle Endeavour lifted off from Kennedy Space Center carrying Unity — Node 1, the first American component of the ISS, a six-port connecting hub that would eventually link half a dozen modules together. Commander Bob Cabana manoeuvred Endeavour to within ten metres of the orbiting Zarya. Mission Specialist Nancy Currie reached out with the Canadarm and grappled the Russian module, bringing it to just above Unity’s berthing port. Cabana fired Endeavour’s thrusters. The two modules came together.
On 10 December 1998, Cabana — American — and Sergei Krikalev — the last Soviet citizen, now a Russian cosmonaut — floated through the hatch together and entered the new station side by side. Neither spoke. The gesture was deliberate. The moment was planned. It was also genuinely felt by everyone watching.
What Zarya and Unity contained, between them, was astonishing: Unity alone held over 50,000 mechanical items, 216 fluid and gas lines, and 121 electrical cables running six miles of wire — all installed by hand, carefully matched to the Russian module’s systems, built to tolerances so precise that two components manufactured on opposite sides of the planet, in facilities that had never communicated directly, fitted together on the first attempt without adjustment.
The station sat empty for nearly two years after that, waiting for Zvezda — the Russian service module that would provide habitation, life support, and propulsion control. Zvezda was delayed by Russian financial difficulties and technical issues, its launch slipping from late 1999 to July 2000. Two Shuttle visits kept the fledgling station maintained and outfitted in the meantime. When Zvezda finally launched and docked autonomously, the three-module complex was ready for its first crew.
Expedition 1
On 31 October 2000, Soyuz TM-31 launched from Baikonur carrying Commander William Shepherd, Soyuz Commander Yuri Gidzenko, and Flight Engineer Sergei Krikalev. The last Soviet citizen was going back to space, this time as a crew member of a station that belonged to no single nation and all of them simultaneously.
They docked on 2 November 2000. Shepherd, floating through the hatch first as commander, called the station “a great place to live and work.” It was the beginning of something that hasn’t ended. As of this writing, humans have been continuously present aboard the International Space Station for over twenty-four years without interruption — through the Columbia disaster, through the years when only a Soyuz could get there, through political crises between the partner nations, through a global pandemic on the surface below. The clock has never stopped.
The station the Expedition 1 crew entered was still skeletal. Three modules, a truss segment, and two docked spacecraft. No laboratory. No Canadian robotic arm. No solar arrays beyond Zarya and Zvezda’s own. The US Destiny laboratory wouldn’t arrive until February 2001, carried up by Atlantis and bolted to Unity’s forward port during five hours of spacewalk. The Canadarm2 followed in April. The Quest airlock, allowing spacewalks without the use of a docked spacecraft, came in July. With each Shuttle flight, another piece was added — nodes, trusses, solar arrays, laboratories — each component tested on the ground, launched in a payload bay, and assembled in orbit by crews whose training had prepared them for contingencies their instructors had invented specifically for this purpose.
The Architecture of Assembly
The engineering achievement of ISS assembly deserves to be understood in full. Sixteen pressurised modules were built by six different nations, in six different countries, using different manufacturing standards, different languages, different engineering cultures, and different technical traditions. They were designed to connect to each other using standardised interfaces developed specifically for the programme — Common Berthing Mechanisms on the American side, SSVP docking systems on the Russian side, with adapter nodes bridging the two. The tolerances required for the pressurised seals between modules were measured in fractions of a millimetre. Every component had to work the first time, in the vacuum of space, operated by suited astronauts using tools designed to function with pressurised gloves. No two module connections could be tested together on the ground before flight — the complete station could only exist in orbit.
It took twelve years to complete. Thirty-seven Shuttle missions contributed to assembly. Additional modules arrived on Russian Proton rockets, Soyuz vehicles, and eventually commercial spacecraft. The truss structure that runs the full width of the station — 109 metres from tip to tip, wider than a football pitch — was assembled from eleven segments, each launched separately, each attached during spacewalks that could last eight hours. The solar arrays that power the station, when fully extended, cover an area of 2,500 square metres. The total pressurised volume is 916 cubic metres — larger than a six-bedroom house, permanently occupied, travelling at 28,000 kilometres per hour in a nearly perfect circle 410 kilometres above the surface of the Earth.
The station passed over the launch sites of every rocket that had ever reached orbit. It passed over Baikonur and Kennedy and Kourou and Jiuquan. It passed over Thumba, where Vikram Sarabhai had launched India’s first sounding rocket from a converted church. It passed over White Sands, where Wernher von Braun’s team had first fired a V-2 in the American desert. It passed over all of it, every 92 minutes, indifferent to the boundaries below.
The Science City
The ISS that emerged from assembly was not merely a structure but a laboratory — the only facility in existence capable of sustained microgravity research over periods of months or years, staffed by humans who could make observations, adjust experiments, and respond to unexpected results in real time.
More than 4,000 experiments have been conducted aboard the station. The range is extraordinary. Protein crystals grown in the station’s microgravity environment form larger and more perfect structures than any achievable on Earth, enabling analysis of molecular shapes that has led to drug development programmes targeting cancer, Duchenne muscular dystrophy, and Parkinson’s disease — a treatment based on station research is in clinical trials. The Twins Study, comparing Scott Kelly’s physiology during a year in space with his identical twin brother Mark on the ground, produced a comprehensive dataset on the effects of long-duration spaceflight on gene expression, the immune system, and cognitive function. The Alpha Magnetic Spectrometer, mounted on the station’s truss, has collected over 100 billion cosmic ray readings — the most comprehensive particle physics dataset ever assembled in orbit, hunting for evidence of dark matter and antimatter.
Fire burns differently in microgravity — without convection, flames form perfect spheres rather than elongated plumes, and the combustion chemistry changes in ways that have revealed previously unknown “cool flame” phenomena, where fuel continues to combust without visible flame. The implications for engine design and fire suppression systems are still being explored. Water is recycled aboard the station at 93% efficiency — a closed-loop life support achievement that represents one of the most sophisticated environmental systems ever built, and which is directly relevant to any long-duration deep space mission that cannot resupply from Earth. Astronauts have grown chilli peppers, lettuce, bok choy, radishes, and over fifty other plant species — beginning to answer the question of whether humans can grow food in space, and whether they will want to eat it.
The medical knowledge accumulated across twenty-five years of continuous occupation has transformed the understanding of human physiology in extreme environments. The ocular syndrome that affects up to half of all long-duration astronauts — in which intracranial pressure causes measurable changes to eyeball shape and vision — was discovered on the station and is now one of the most actively researched challenges in space medicine. The countermeasures for bone and muscle loss developed on the station have already been adapted into treatments for osteoporosis patients on Earth. The station has served simultaneously as a laboratory for space exploration, a test facility for Mars mission planning, and a medical research platform for conditions that affect millions of people who will never leave the ground.
The Human Dimension
What the numbers and the science don’t capture is what it is actually like to live there. The station rotates once per orbit to maintain thermal equilibrium, which means the sun rises and sets every 45 minutes — sixteen sunrises per day. The cupola, a seven-windowed observation module added in 2010 at the suggestion of Sergei Krikalev, who had spent long months on Mir looking through a single 43-centimetre porthole and wanted something better for the people who came after him, offers a view of Earth that no photograph fully conveys. Astronauts who have looked through it describe the same involuntary response: silence, and a feeling that cannot quite be named.
The daily routine involves two hours of mandatory exercise — to fight the bone and muscle loss that begins within days of arrival in weightlessness — followed by science operations, maintenance, resupply management, communication with Mission Control, and the ordinary domestic details of a house that has no floor and no ceiling. Meals are taken floating at a table, the food anchored by Velcro and surface tension. Sleep happens in small personal cabins, in sleeping bags fixed to the wall, in a station that is never fully dark and never fully quiet — the life support systems run constantly, the fans and pumps producing a background hum that every crew member learns to sleep through and eventually stops hearing.
The station has hosted 273 people from 21 countries over its operational life. It has been reached by Space Shuttles, Soyuz capsules, SpaceX Crew Dragons, and Boeing Starliner. Its longest-duration resident was Oleg Kononenko, who surpassed 1,000 days in space across multiple missions in 2024. Scott Kelly and Mikhail Kornienko spent a full year aboard together in 2015 and 2016, the most comprehensive single-mission physiological study ever conducted. Peggy Whitson commanded the station three times. Christina Koch spent 328 days on a single mission, the longest by a woman in history.
The relationships forged aboard the station have sometimes outlasted the geopolitical relationships between the nations that sent its crew. American astronauts and Russian cosmonauts who trained together, lived together, and trusted each other with their lives have maintained personal friendships through political crises that froze official cooperation. When Russia’s invasion of Ukraine in 2022 prompted the severance of most US-Russian space cooperation, the astronauts and cosmonauts on the station continued to operate it together, eat meals together, and hand over systems to each other at crew rotation. The partnership that had been built on trust was more durable than the politics.
What It Represents
The International Space Station cost approximately $150 billion to build and operate across its lifetime — the most expensive object ever constructed by human hands. It was saved by a single congressional vote. It was born from the collapse of the Soviet Union. Its first module was built from the hardware of a cancelled laser weapon. Its two halves were manufactured on opposite sides of the Iron Curtain and fitted together in orbit on the first attempt without a gap.
There is a photograph taken from the station that captures something essential about it. The Earth fills the bottom third of the frame. The station’s solar arrays extend across the middle, catching sunlight. In the far distance, a small bright point moves against the stars — a Soyuz or a Shuttle or a Dragon, approaching from below. The photo could have been taken at almost any point in the last twenty-five years. The people inside the frame, and the people in the vehicle approaching it, came from different countries that had once aimed nuclear weapons at each other. They were going to live together in a room the size of a house, 400 kilometres from the nearest ground, travelling at eight kilometres per second, for six months. They had trained for this together. They trusted each other. They would come home changed.
The station is scheduled for deorbit in 2030, when its structure will have reached the end of its engineered lifetime. What replaces it — whether commercial stations, national stations, or a new international partnership — is still being negotiated. The debates are political, financial, and technical simultaneously, which is exactly what they were in 1984 when Reagan first announced the programme that would eventually, by one vote and one cold war’s end, become this.
In 1992, a reporter asked Sergei Krikalev — the last Soviet citizen, floating above a planet that had just reorganised itself beneath him — what surprised him most about everything that had changed. He said the Earth had turned from dark to white, and now it was beginning to bloom again. He meant the seasons. He might have meant something else too.