Even before humans first went into orbit, there had been dreams of establishing a permanent presence in space.
For almost the last 25 years, humanity has achieved just that. At least one human being has been in Earth orbit without interruption for almost a quarter century.
What has allowed this to happen is one of the most complex and expensive things ever built.
Learn more about the International Space Station, its history, and its future on this episode of Everything Everywhere Daily.
Even before Yuri Gagarin was launched into space, people began thinking about how we could permanently live in space.
Konstantin Tsiolkovsky, the Russian rocket researcher who is considered to be the father of rocket science, envisioned people living permanently in space at the start of the 20th century. In 1929, the Slovenian theorist Herman Poto?nik was the first to envision a rotating wheel in orbit that could simulate the Earth’s gravity.
Werner von Braun, the head of the German and later American rocket programs, wrote about a Poto?nik style space station in a 1951 magazine article.
So, the idea of having a place to go in Earth orbit was nothing new and even predated actual human space flight.
When humans did final make it to space in the early 1960s, it became obvious they had nowhere to go. Each flight was in a tiny capsule for a short amount of time.
The Americans did eventually find a destination for their space program, the moon.
The Soviets, however, never really made a serious attempt at landing humans on the moon like the Americans did. They perused another strategy of creating space stations.
The first space station in history was Salyut 1, which launched in April 1971. There were only two trips to Salyut 1, and both did not go according to plan. Soyuz 10 failed to dock. Soyuz 11 did manage to dock, and the crew spent 23 days on board, but the three-man crew was killed upon reentry.
The Americans canceled the last three Apollo missions to fund their own space station project called Skylab. Skylab was built out of a modified Saturn V rocket and was launched on Mary 14, 1973. Over the next nine months, it was occupied by three crews for a total of 24 weeks.
After Skylab, all space station activity for almost the next twenty-five years was by the Soviets.
They launched five more Salyut space stations that could host cosmonauts for longer and longer lengths of time.
This culminated in the Mir space station in 1986. Mir, which is the Russian word for peace, was the first modular space station. It consisted of several different sections which were flown to orbit on different missions and then assembled by cosmonauts in orbit.
Mir smashed all previous space station records. Where Salyut 7 had been occupied for a total of 861 days, Mir was occupied for a total of 4,594 days, or over 12.5 years, 3,644 days of which were consecutive.
The Americans during this period had plans for a space station that never materialized. A space station named Freedom was supposed to be the primary destination for the Space Shuttle. It was to have modules built by the European and Japanese space agencies, but the space station never materialized, given the space shuttle nowhere to go.
What changed everything was the end of the Cold War. With the Soviet Union gone, the space race wasn’t so much a rivalry anymore.
Russians and Americans found it easier, and cheaper, for both countries to work together.
The first and most obvious way to cooperate was to have the Space Shuttle dock with the Mir space station. Between 1994 and 1998 there were 10 shuttle flights to Mir, carrying Russian cosmonauts on board.
While having the shuttle fly to Mir was a cheap and obvious solution, it wasn’t a long term solution. Mir was a wholly owned and controlled Russian space station, and it was limited in terms of size and mission life.
When the Shuttle-Mir program was announced in 1993, the Russians and the Americans also announced that they would jointly develop a new space station.
The Americans dusted off the plans for the unbuilt Space Station Freedom and adapted it for a new space station which would be built with international partners. They also had access to the two decades of Russian experience with their multiple space stations.
The new space station was dubbed the International Space Station or ISS, and it would be significantly larger than Mir. Where Mir could host a crew of three, the ISS could host seven and as many as 13 temporarily.
The ISS was to be modular, so each segment of the space station could be built and launched separately, just so long as everything managed to fit and work together in the end. That meant that each international partner in the project could work on and deliver their own segment.
The first module of the ISS was launched in November 1998. It was the Zarya module built by the Russians, also known as the Functional Cargo Block. This module served as the core to build off of as it provided electricity, storage, and propulsion.
Two weeks later, the Americans launched the Unity module. The Unity module allowed the Space Shuttle to dock and has an airlock that allows astronauts to go outside for spacewalks.
This was followed by the Russian-built Zvezda module, which provided crew living quarters and life support systems for the ISS.
These modules serve as the core of the station, and once they were in place, it was possible to start hosting astronauts.
The first mission to the International Space Station was Expedition 1, which was launched from the Baikonur Cosmodrome in Kazakhstan. They arrived at the station on November 2, 2000.
Since their arrival, there has been a continous human presence on the ISS. As of the day I am recording this episode, humans have been on the ISS and in space for 22 years and 185 days straight.
These modules were just the beginning of what the space station would become. The ISS was constructed over a span of eleven years, from 1998 to 2011.
Additions included multiple nodes, modules, habitats, and laboratories. It also included the largest and most visible part of the ISS, the Integrated Truss Structure.
The Integrated Truss Structure is the 110-meter -metal truss system that supports the solar panels and antennas for the space station.
The space station was not just a joint Russian and American effort. There were contributions by other space agencies as well.
The Columbus science laboratory was constructed by the European Space Agency, as was the cupola, which is a windowed observation module.
The Japanese provided the Kib? experiment module. The Canadian Space Agency provided Canadarm2, which is the primary robotic arm on the space station, as well as Dextre, which is a two-armed robot.
While the ISS was declared complete in 2011, it has been constantly maintained, and additional modules have been added as recently as 2021.
The International Space Station holds many superlatives. It is the largest man-made object in history to fly in space. It has a total span that is the size of a football field, regardless of which type of football you consider.
The total mass of the space station is over 450,000 kilograms or 990,000 pounds.
It travels at a speed of 17,500 miles per hour or 28,000 kilometers per hour at an altitude of approximately 250 miles or 400 kilometers.
It also has the distinction of being the most expensive object ever built, with an estimated cost of over $150 billion.
Since the first crew members entered the station in November 2000, 266 people have visited the ISS. There have been 162 Americans, 57 Russians, 11 Japanese, 9 Canadians, 5 Italians, 4 French, 4 German, 2 Emerati, and one from Belgium, Brazil, Denmark, Great Britain, Kazakhstan, Malaysia, the Netherlands, South Africa, South Korea, Spain, Israel, and Sweden.
There is a major problem with a space station of this size and at this altitude.
The ISS is in low Earth orbit. At this altitude, it is almost a total vacuum. Almost, but not quite. There are just enough gas molecules at this altitude to cause a tiny bit of atmospheric drag. Traveling at such incredible speeds, the drag can add up even though it is quite small.
If nothing is done, the ISS would lose 2 kilometers a month in altitude due to atmospheric drag. The lower your altitude, the more drag you experience, dropping your altitude even faster.
The ISS has to regularly boost itself to a higher orbit to compensate for atmospheric drag. These adjustments requires 7.5 tons of fuel per year.
The ISS needs to be constantly resupplied to provide food, water, and fuel for the astronauts. These resupply missions are conducted without passengers on board and are mostly handled by private contractors, in particular SpaceX and Northrop Grumman.
Despite having served far longer than any other spacecraft in history, the International Space Station is nearing the end of its life span. The big question has been what to do with it.
Currently, the ISS is scheduled to operate at least through 2024, although there are plans to extend its mission through 2028 or 2030. Regardless how long its lifespan is extended, this is almost certainly the last decade for the International Space Station.
In addition to the general wear and tear of being in space for a quarter century, the political situation has deteriorated between the main partners, the United States and Russia. It is unlikely that future cooperation is possible or even desired.
Furthermore, technology has changed, in some cases dramatically. Continuing to throw money at something outdated doesn’t make sense after a point, and that point has already arrived.
The big question is, what do you do with it?
One option was to send it to an even higher orbit where it would be safe. The higher the orbit, the less drag, and the longer it takes for an orbit to decay. This would at least allow the option of mothballing the station for use at a later date.
Another option is to just do nothing. Given the drag on the space station, it would deorbit on its own in about 12-18 months. The problem with that is that it is so large that significant pieces of it will probably hit the Earth, which is exactly what happened with both Skylab and Mir.
The most probable fate of the ISS will be a controlled deorbiting. The current plan is to deorbit the ISS in 2031. It would probably require a special module to push the entire space station so that it deorbits at the right time and place.
The final resting place for the International Space Station will be somewhere around Point Nemo, the most isolated place on Earth in the southern Pacific Ocean, of which I’ve done a previous episode.
Will the end of the International Space Station mean the end of a permanent presence of humans in space?
Almost certainly not, but it is possible there could be a gap between the end of the ISS and whatever comes after it. It could be that the gap is filled by a Chinese space station.
NASA’s Artemis program is planning for a space station in lunar orbit, but perhaps not with a permanent crew.
The current thinking is that NASA might just leave the creation of another space station up to private companies who could do it at a much lower cost. Also, instead of one large space station, there might be several smaller ones with different purposes.
Regardless of what the future has in store for the International Space Station, for the last 25 years it has been the focal point of human space exploration and space science. It is the largest and most complex object ever to fly in space and the most expensive thing which has ever been built by humans.