Watch a visual history of the ISS: The Station

On November 2, 2000, astronaut Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev arrived at the International Space Station. The moment began a permanent human presence in space.

Over the past two decades, 240 people from 19 countries have stayed in the world’s premiere orbital laboratory. The station is a paragon of space-age cosmopolitanism, but this enduring international cooperation was hard-won. 

The ISS was shaped by the politics of the Cold War, and the difficult decisions made by statesmen, soldiers, and NASA officials, when there were still astronauts bouncing around on the moon. The geopolitical tensions of the last century are baked into the very architecture of the station, which is arguably best described as two stations — one Russian, one American — that are attached at the hip. Even so, the station is more than a technical marvel; it is a triumph of diplomacy and an unprecedented experiment in the use of science and technology as instruments of soft power. 

NASA had wanted a space station ever since it started sending people to space in the late 50s. But it wasn’t until it had boot prints on the moon that the idea was really taken seriously. The original plan was to put a 100-person station called Space Base in low Earth orbit. However, it soon became clear that the cost of using expendable rockets to boost people and supplies to orbit would dwarf the cost of building the station itself. If NASA wanted an orbital outpost, it was going to have to build a reusable spacecraft. 

NASA stood up its shuttle program in the early 1970s and from the start, it was designed to have international contributors. This was a major departure from the Apollo program, which was notable for its deeply nationalistic motivation. Putting a man on the moon was first and foremost about demonstrating American superiority vis-a-vis the Soviet Union. But after Armstrong took that small step, there was a major shift in the official policy of the space program.

The US realized that fostering international collaboration in space was the most effective way to maintain American dominance in the final frontier — and on Earth.

This tension between prioritizing American interests and fostering internationalism could already be seen in the early days of the shuttle program. NASA initially invited Canada, Europe, and Japan to participate, though Japan would deliberate too long and ultimately lose the opportunity. But despite the international enthusiasm for the project, NASA didn’t intend for all countries to be equal participants. The shuttle was an American spacecraft that would primarily serve US interests.

This, understandably, led to some tension on the project, particularly between the US and Europe. When NASA first invited the European countries to collaborate on the shuttle, they spent years — and tens of millions of dollars — figuring out the best way to contribute. There were three main options: Europe could build a tug that took payloads from the shuttle and put them in their proper orbit; it could build certain components of the shuttle, like the bay doors; or it could build a laboratory module that would fly in the shuttle bay.

Europe eventually decided it wanted to contribute a tug, but NASA wasn’t having it. The agency wasn’t thrilled about having to rely on other countries for a critical shuttle component, especially since the spacecraft would sometimes fly sensitive national security missions. 

Instead, NASA tasked Europe with building Spacelab, a laboratory module that could fit inside the shuttle’s payload bay. It wasn’t what Europe wanted to build, but it eventually agreed to the proposal — and only after some hard negotiations. France was particularly resistant to the idea of building Spacelab. It preferred Europe stand up its own spacefaring capabilities, and building Spacelab would mean it wouldn’t have enough money to invest in ambitious European space projects. It was only after the other member states agreed to let France lead the development of the Ariane rocket that it signed on to the US shuttle project. 

By the time the space shuttle flew for the first time in 1981, NASA was itching to put it to use building a space station. In 1982, it enlisted eight major aerospace contractors to draft up concepts for stations that would ultimately inform the agency’s final design. That same year, NASA stood up a Space Station Task Force to determine whether international cooperation on the space station was feasible — or even desirable. 

The question is more complicated than it sounds. NASA wasn’t alone in wanting a permanent base in low Earth orbit. The US Department of Defense had also been pursuing a station of its own for years, and the Reagan administration’s support for the ISS was contingent on its use as a platform for fostering extraterrestrial commerce. This meant that NASA’s space station would have to juggle the requirements of science, industry, and defense, which tended to have very different attitudes toward international cooperation. 

The DOD was particularly resistant to the idea of outsiders snooping around American hardware, or having to trust the reliability of foreign components. “The DOD called a halt to the space station negotiations and tried to torpedo them,” says John Logsdon, a space historian at George Washington University. “The DOD wanted a US-only facility.” The main concern for the military — and the businesses that were supposed to become the main users of the space station — was technology transfer. With people from all these different countries swapping data to build the ISS, it seemed inevitable that some of America’s valuable or classified technical knowledge would leak to its partners.

NASA, on the other hand, was concerned about how other countries would react to American defense payloads being flown on the station; presumably, they wouldn’t be thrilled about the idea of contributing to a project that served to boost America’s military power. “On the one side, NASA had to meet the demands of its international partners, and on the other side, it had to create terms and conditions that were acceptable to the national security community,” says Logsdon.

As NASA grappled with international collaboration issues, the push for a space station gathered momentum at the highest levels of government. In 1984, US President Ronald Reagan officially announced America’s intention to build a space station during his State of the Union address. To the surprise of many, he also invited America’s allies to participate in the program. At that point, NASA hadn’t yet figured out how to make that happen without entirely alienating the DOD or potential commercial users, not to mention the international collaborators themselves. 

Some countries in the ESA still felt a little burned from how NASA had handled international collaboration on the space shuttle. As Logsdon recounts in Together in Orbit: The Origins of International Participation in the Space Station, some members of the European space community described collaborating with the US on the shuttle as a “stupid” mistake because it undermined Europe’s abilities to independently develop its own comparable technologies. 

NASA was well aware of these residual hard feelings, and the agency’s leadership was determined to do things differently with the space station. This time they brought in their international collaborators — Europe, Japan, and Canada — in the earliest stages of planning. Although NASA would still lead the space station program, its partners would influence development from the beginning, to ensure the station met everyone's needs and abilities.

As for the technology transfer problem — and the question of military payloads — this would be handled through the design of the station itself. Because the station was modular, this meant each country could build its piece of the station and limit the amount of data it shared with partners. The interfaces between the modules would be “clean,” meaning they wouldn’t contain any sensitive components.

In short, international politics ultimately influenced the design of the space station at an engineering level. 

By 1987 the space station had a name — Freedom — and the US formally signed agreements with Europe, Japan, and Canada to develop the orbiting outpost a year later. But the agreement turned out to be premature. Ever since Reagan announced the space station in 1984, NASA had struggled to settle on a design that was both practical and affordable.

Space station plans went through seven major redesigns between 1984 and 1993. That was the year the station’s first components were supposed to be flying in space, but by that point NASA had spent 9 billion dollars designing a station it hadn’t even started building yet. Congress was fed up with what many of its members saw as an extravagant and wasteful project. That same year the entire space station program avoided being canceled by a single vote in the US House of Representatives. Clearly, something had to change. 

A few months after that fateful vote, the Clinton administration canceled plans for space station Freedom. Instead, NASA would build an “International Space Station.” This was mostly a way for the US to keep its space station without breaking the bank. But it was also influenced by an invitation to collaborate from an unlikely new partner: Russia. “A faxed letter from the two heads of the Russian space program came more or less out of the blue and suggested merging Russia’s Mir-2 and space station Freedom,” says Logsdon. “And the White House, after debating this for a few months, decides it's a good idea to invite Russia to join this station.”

Space had already proven to be a powerful diplomatic tool in US-Soviet relations. The infamous “handshake in space” between NASA astronauts and Russian cosmonauts in 1975 is generally seen as the beginning of the end of the Cold War. Even though the threat of Soviet dominance in space was used as one of the Reagan administration’s justifications for space station Freedom, by the time the Clinton administration announced the International Space Station the relationship between the US and Russia had been defrosting for years. The Soviet Union dissolved in 1991, and so when Russia reached out to propose merging space stations, the US saw an opportunity to get the post-Cold War world off on the right foot.

In 1993, the US and Russia hosted the first in a series of high-level meetings to discuss collaborating on the International Space Station. As a stepping stone toward the space station, the US and Russia conducted a series of joint shuttle missions to Mir. The shuttle-Mir program ended in 1998, and that same year, the 15 partner nations on the International Space Station officially agreed to a memorandum outlining their contributions and responsibilities for the ISS. Although NASA would still lead the station’s development, Russia would be the de facto second in command. It would contribute a habitation module, a laboratory module, some Soyuz emergency lifeboats to save the station crew in event of an emergency, and a propulsion module to keep the station in a stable orbit.

The first piece of the space station, a Russian cargo module, was boosted into orbit on a Russian Proton rocket a few months later. Almost exactly two years after that, the fledgling International Space Station station would receive its first occupants — two Russian cosmonauts and an American astronaut. It’s been hosting a rotating crew of people from around the world ever since.

The ISS was officially completed in 2011. It’s often presented as a model of international collaboration and harmony, but it hasn’t entirely shed the political baggage that created it. The ISS is, in a way, two different space stations: One’s Russian, the other American. Almost everything you hear and see about the space station is from the American side of the station, which includes the European and Japanese modules; it is relatively rare to get a peek behind the curtain at the Russian side.

This is an artifact of the concerns about technology transfer and makes the ISS feel more like a truce than a partnership. Astronauts and cosmonauts may ride the same rockets to the station (for now) and eat dinner together at the same table, but as far as the countries themselves are concerned, this friendship has well-defined limits. Indeed, the very existence of the ISS depended on making these limits to collaboration explicit to all the countries involved. And despite this soft divide, neither space station could exist without the other. “The reality is that the system we have has become mutually interdependent,” says Logsdon.

The ISS will likely go down in history as the first — and last — space station of its kind. A global resurgence of nationalism coupled with the commercialization of low Earth orbit all but guarantees that the space stations of the future will look more like walled gardens than international commons. China is developing its own space station and multiple American companies have already started rolling out the hardware for the first private space stations in orbit. But the ISS will always serve as a reminder that international collaboration in space for the betterment of the entire species is possible, no matter how unlikely it may sometimes seem from the ground.