The ISS Is Entering Its Final Years. What Did We Learn Up There?
For more than 25 years, people have lived
continuously in orbit. The International Space Station has been a laboratory,
construction site, diplomatic experiment and improvised home all at once. Now,
with retirement planned around 2030, its final chapter is becoming visible.
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| For more than 25 years, the International Space Station has been humanity’s permanent home in orbit — a laboratory, engineering testbed and stepping stone toward deeper space exploration. |
Every 90 minutes, the International Space
Station completes another lap of Earth. Moving at roughly 28,000 kilometers per
hour, it gives the crew about 16 sunrises and 16 sunsets every 24 hours. The
scale is just as strange: a football-field-sized structure, assembled piece by
piece, racing about 400 kilometers above us.
The speed is impressive. The routine is
stranger. Astronauts spend their days troubleshooting stubborn hardware,
exercising, cleaning filters, running experiments, calling home and floating to
a window to photograph a thunderstorm or aurora far below. At this scale,
spaceflight starts to look less like a heroic expedition and more like keeping
a very complicated house alive.
Since the first long-duration crew arrived
in November 2000, someone has always been aboard. The station turned what had
once been short visits to space into something closer to residency — humanity's
first long-lived home away from Earth.
That experiment now has an end date. The
United States, Canada, Japan and the European partners have committed to ISS
operations through 2030, and Russia currently plans to operate its segment
through the same year. NASA is preparing for a controlled deorbit while private
companies race to build the stations that may follow.
That makes this a better moment to ask something larger than 'What is the ISS?' After a quarter-century of living above the planet, what did we actually learn?
A Space Station Built One Launch at a Time
The ISS did not arrive in orbit as a
finished spacecraft. Its first element, Zarya, launched in November 1998. Two
weeks later, the U.S.-built Unity module joined it. Over the following years,
modules, trusses, solar arrays, radiators, laboratories, docking nodes and
robotic systems arrived on dozens of missions. NASA counts 42 assembly flights
— 37 by the Space Shuttle and five by Russian Proton or Soyuz rockets.
That history matters because the station is
not really one spacecraft. It is a patchwork of systems built by different
nations, often at different times, that had to function as one machine. Five
agencies — NASA, Roscosmos, ESA, JAXA and the Canadian Space Agency — operate
it, representing a partnership across 15 countries.
The political symbolism is hard to ignore.
The station grew out of the post-Cold War merger of several earlier concepts
and became an engineering project in which no single partner could simply do
everything alone. It is expensive, imperfect and extraordinarily complicated —
yet it kept operating through major political tensions on Earth.
For the broader story of how the U.S. space
program moved from Apollo to today's Artemis era, see our updated history of NASA. The ISS sits
right in the middle of that transition: after the race to the Moon, before a
sustained return beyond low Earth orbit.
The ISS in Numbers
|
Fact |
ISS |
|
Continuous
human presence |
Since
November 2000 |
|
Orbital speed |
About 28,000
km/h (17,500 mph) |
|
One orbit |
About 90
minutes |
|
Sunrises and
sunsets |
About 16 of
each every 24 hours |
|
End-to-end
length |
109 meters |
|
Mass |
About 420
metric tons |
|
Habitable
volume |
About 388
cubic meters, excluding visiting vehicles |
|
Typical crew |
Around seven;
sometimes more during handovers |
|
Visitors by
2026 |
295 people from 26 countries |
|
Research
legacy |
More than 4,000 investigations involving
researchers from over 100 nations |
What Is It Actually Like to Live on the ISS?
Forget the sleek starships of science
fiction. The ISS feels more like a laboratory, machine room and crowded shared
apartment — except the entire apartment is in continuous free fall around
Earth.
NASA describes the living and working space
as larger than a six-bedroom house. There are sleeping quarters, two bathrooms,
exercise equipment and the Cupola — the famous seven-window observation module
that gives astronauts one of the most extraordinary views available to any
human being.
Yet almost every mundane action becomes
engineering. A glass of water cannot simply sit on a table. Crumbs can become
floating debris. Sweat does not drip normally. Tools need Velcro, tethers or
carefully designed storage. Fire behaves differently because hot air does not
rise in the familiar way. Even going to the bathroom requires airflow to
replace gravity.
Then there is the body. In microgravity,
muscles and bones no longer carry the same loads they do on Earth. Astronauts
exercise at least two hours a day to slow the loss of muscle and bone. The
vestibular system also has to relearn what 'up' means — one reason many people
experience space adaptation syndrome during their first days in orbit.
We explore that short-term disorientation
in more detail in Space Sickness: What to Expect Beyond Earth.
The longer-term effects become even more important when imagining settlements
on Mars, where gravity is only about 38% of Earth's; see How the Human Body Will Change on Mars.
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| The Cupola is both the ISS’s most spectacular viewpoint and a working observation station used for spacecraft monitoring, robotic operations and Earth photography. |
The Weirdest Household in Human History
Some of the best ISS facts sound almost
silly until you imagine living with them for six months. There is no washing
machine. Clothes are worn repeatedly, then packed into disposable cargo
vehicles that burn up during re-entry. That may be workable when resupply
arrives regularly; it makes far less sense on a Mars mission, where every
kilogram of water, detergent and spare clothing matters.
The Cupola, meanwhile, is famous as the
station's best window — but it was not installed simply to give astronauts
somewhere beautiful to sit. Its seven windows let crews monitor approaching
spacecraft, spacewalks and robotic operations. A workstation inside can control
Canadarm2, the Canadian robotic arm used to move equipment and capture visiting
vehicles. The most cinematic room on the ISS is also a serious piece of
industrial infrastructure.
Despite the isolation, the station is
surprisingly connected to the planet below. Its orbital path passes over more
than 90% of Earth's population. Around dawn or dusk, sunlight reflecting from
the station can make it visible to the naked eye as a bright point crossing the
sky. For a few minutes, a place where people are eating dinner, repairing
equipment and running experiments can look like a moving star.
These details are easy to dismiss as
trivia. In reality, they reveal why long-duration spaceflight is hard. A
permanent orbital habitat must solve not only propulsion and life support, but
laundry, exercise, storage, noise, hygiene, sleep, repairs, privacy and
hundreds of other problems that rarely appear in concept art. Space exploration
becomes real when the heroic problems give way to household problems.
The Station Drinks Its Own Water — Almost
One of the most useful technologies aboard
the ISS is also one of the least glamorous: water recycling.
On a mission to Mars, carrying years of
drinking water from Earth would be brutally expensive. The station therefore
serves as a test bed for closed-loop life support. In 2023, NASA reported that
the U.S. segment demonstrated roughly 98% total water recovery. The system
collects moisture from cabin air, wastewater and urine-processing streams, then
purifies it until it is safe to drink again.
The joke that astronauts are drinking
yesterday's coffee tomorrow is not entirely wrong. But that is exactly the
point. A future deep-space crew cannot afford to throw water away. The ISS has
spent decades teaching engineers how to turn a spacecraft from a vehicle
supplied constantly by Earth into something closer to a small artificial
ecosystem.
The Most Important Thing About the ISS Is Not the View
The spectacular photographs are what most
of us see. The real reason the ISS exists, however, is that it provides
something almost impossible to reproduce on Earth for long periods: sustained
microgravity with humans, laboratories and regular access to cargo.
Microgravity does not simply make objects
float. It changes the rules by which fluids move, crystals grow, flames burn,
cells organize and the human body maintains itself. Remove gravity as a
dominant force and processes that look ordinary on Earth can behave in
surprising ways.
That is why the station has hosted
thousands of experiments. NASA reports more than 4,000 investigations over its
history, involving researchers from more than 100 nations. In 2025 alone, crews
supported more than 750 investigations aboard the orbiting laboratory.
1. Human Bodies Become Experiments
Astronauts do not merely operate the
laboratory; they are part of it. Long stays in orbit have revealed changes in
bone density, muscle, vision, immune function, cardiovascular regulation and
fluid distribution. You cannot plan a safe Mars mission without understanding
what months of altered gravity, isolation and radiation do to the human body.
Some of the most valuable station research
therefore looks less like futuristic space science and more like medicine.
Researchers use blood samples, ultrasound, wearable sensors and compact tissue
models to understand how human biology responds when one of its oldest
environmental constants — gravity — is reduced almost to zero.
2. Tiny “Organs” Go to Space
One of the more fascinating approaches uses
tissue chips: small devices containing human cells arranged to mimic aspects of
real organs. In microgravity, some biological processes change in ways that are
difficult to reproduce on Earth, giving researchers another route to study
disease, aging and potential treatments.
The station has also become a test site for
bioprinting. Experiments have printed structures including knee meniscus
material and live human heart tissue. These are not transplant-ready organs —
that distinction matters — but the work tests whether microgravity can help
delicate biological structures form without collapsing under their own weight.
3. The Coldest Laboratory You Have Never Visited
The Cold Atom Laboratory is roughly the
size of a small refrigerator, yet it can cool clouds of atoms to temperatures
extraordinarily close to absolute zero. Under those conditions, atoms begin to
reveal quantum behavior on scales that are easier to study.
In 2018, the facility produced
Bose-Einstein condensates in orbit. In 2026, astronauts installed an upgrade
that expanded what scientists can do with the system. The payoff is not a
consumer gadget tomorrow; it is a better laboratory for testing quantum physics
and developing sensing and navigation techniques that could eventually matter
both on Earth and in deep space.
4. A Machine Shop 400 Kilometers Above Us
In 2014, the ISS produced the first
3D-printed object in space. Soon afterward, engineers uploaded a digital file
from Earth and the printer made a ratchet wrench in orbit. A decade later,
station experiments had moved on to metal printing, electronics repair and
biological printing.
For a Mars crew, that capability could be
more than convenient. If a mission is months or years from Earth, manufacturing
a replacement bracket or tool from a digital design may be more practical than
carrying every spare part that could possibly fail.
In August 2024, an ESA experiment produced
the first metal 3D-printed product aboard the station. In September 2026, crews
were working on cartilage bioprinting and lead-free soldering experiments — a
reminder that even in its final years, the ISS is still testing technologies
that future explorers may depend on.
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| The ISS is not one experiment but thousands: researchers use microgravity to study physics, human biology, plant growth, materials and technologies designed for future missions beyond Earth. |
5. Learning How to Grow Dinner Off Earth
Plants have been part of the station's
research program for years. Astronauts have grown lettuce, zinnias and chile
peppers, while newer experiments examine how crops respond to different
moisture levels, lighting and root environments.
Food is only part of the story. Plants
recycle carbon dioxide, produce oxygen, provide fresh nutrients and can have
psychological value for crews living for months inside a metal habitat. A Mars
greenhouse will not be a decorative garden. It may become part of the
settlement's life-support architecture.
Did ISS Science Actually Help People on Earth?
This is where space-station storytelling
can become too promotional, so it is worth being careful.
Not every ISS experiment produces a
breakthrough. Some results are incremental. Some experiments fail. Others are
useful mainly because they reveal what does not work. And a result obtained in
microgravity does not automatically become a treatment, product or technology
on Earth.
But the station's value is cumulative. It
has improved understanding of osteoporosis-like bone loss, muscle atrophy,
fluid shifts and immune changes. It has tested water-recycling systems,
combustion science, plant growth, remote medical procedures, advanced
materials, 3D manufacturing and hundreds of technologies meant for future
exploration.
Perhaps the station's greatest scientific
contribution is not one spectacular invention. It is the accumulated record of
what happens when humans stop visiting space briefly and start living there
year after year.
The ISS Quietly Became a Bridge to Commercial Spaceflight
For most of its early life, the station was
overwhelmingly a government project. That has changed as commercial
transportation, research and privately organized missions have become part of
everyday ISS operations.
SpaceX Dragon now carries astronauts and
cargo routinely, commercial research hardware operates onboard, and Axiom Space
has flown four privately organized astronaut missions to the ISS. Those crews
have included private individuals as well as government-sponsored astronauts
from countries without their own orbital transport program. Axiom Mission 5 is
targeted no earlier than January 2027.
That is also the economic model NASA wants
after the ISS. Instead of owning and operating the next giant station, the
agency plans to buy services from commercially owned platforms — much as it
already buys transportation from private companies.
That shift connects directly to the broader
emergence of commercial space tourism — although the future
market is likely to be about far more than wealthy passengers. Research,
manufacturing, government missions, national astronaut programs and private
crews may all compete for the same orbital infrastructure.
Why Not Just Keep the ISS Forever?
The simple answer is that the ISS was never
designed to be immortal. Keeping a huge integrated structure alive after three
decades in orbit eventually becomes an engineering and financial problem of its
own.
Its structure has endured decades of
thermal cycling: scorching sunlight, deep shadow, sunlight again — every orbit.
Components age. Micrometeoroids and orbital debris leave scars. Seals,
electronics, radiators, pumps and pressure structures all have finite service
lives. The station can be repaired and upgraded, but maintaining it
indefinitely becomes less practical as the hardware grows older.
There is also a strategic reason. NASA
wants to spend less of its human-spaceflight budget operating a laboratory
close to Earth and more on the Moon, Mars and technologies for deeper
exploration. The plan is not to abandon low Earth orbit. It is to stop being
its primary landlord.
How Do You Dispose of a 420-Ton Space Station?
The answer is not 'let it fall.' A station
this large needs a controlled end.
Atmospheric drag will eventually pull any
low-Earth-orbit spacecraft down, but the ISS is far too large to leave to
chance. NASA and its partners plan a controlled re-entry aimed at an
unpopulated stretch of ocean.
SpaceX was selected to develop the U.S.
Deorbit Vehicle, a purpose-built spacecraft that will provide the propulsive
capability needed for the final maneuver. NASA will own and operate the vehicle
after development. The station and the deorbit spacecraft are expected to break
apart during re-entry; some dense components will survive long enough to reach
the ocean.
It will be a strange ending. One of the
most complex objects humanity has ever built will not be preserved intact in a
museum. Most of it will burn up in the atmosphere; surviving debris will be
steered toward the ocean.
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| From the first modules in 1998 to continuous human occupation, in-space manufacturing and advanced research, the ISS has evolved from a construction project into one of humanity’s most important orbital laboratories. |
What Comes After the ISS? Probably Not Another ISS
There probably will not be a single 'ISS
2.' The post-ISS era may look more like an ecosystem: several smaller stations
competing for government missions, researchers, manufacturers and private
customers.
NASA is already supporting several
commercial station efforts and preparing the next phase of its Commercial Low
Earth Orbit Destinations strategy. The goal is a market in which NASA is one
customer among many rather than the owner of one enormous orbital complex.
Three projects show how different those
models could be.
Vast Haven-1: Start Small
Vast currently targets Haven-1 for launch
in 2027. It is dramatically smaller than the ISS, with room for four people and
missions designed to last roughly two weeks. The company's Haven Demo test
spacecraft launched in 2025 and completed a controlled deorbit in February 2026
after a three-month technology-demonstration mission.
Haven-1 is not a replacement for the entire
ISS. It is a test of whether a private company can build, launch and operate a
crewed orbital habitat on a much tighter scale. Vast's longer-term Haven-2
concept is intended to grow toward continuous occupation around the end of the
decade.
Axiom Station: Grow Out of the ISS
Axiom Space is taking a different route.
Its plan starts with station hardware that can initially connect to the ISS.
Under a revised assembly sequence, a two-module Axiom Station could separate
and operate independently as early as 2028, if the schedule holds.
The concept is almost evolutionary: use the
existing station as a construction and operational bridge, then detach a new
commercial habitat before the old one disappears.
Starlab and the Race to Become the Next Orbital Laboratory
Starlab is another major commercial-station
effort. In February 2026, it completed a NASA-attended Commercial Critical
Design Review, moving the project from design validation toward manufacturing,
integration and testing.
Other concepts, including Orbital Reef,
remain in the broader commercial-station landscape. The larger point is that
NASA does not want the post-ISS era to depend on a single successor.
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| The post-ISS era may look less like one giant replacement station and more like an ecosystem of commercially operated orbital laboratories serving governments, researchers and private customers. |
So, Was the ISS Worth It?
The ISS was never cheap, and it never made
human spaceflight cheap. So whether it was 'worth it' depends on what problem
you think it was supposed to solve.
If the goal was cheap access to space, the
ISS did not deliver it. The station is expensive, complicated and dependent on
frequent logistics from Earth. It is not a self-sustaining colony. It did not
make living in orbit routine in the way science fiction once imagined.
If the goal was to learn whether humans
could build, maintain and continuously inhabit an enormous orbital complex for
decades, the verdict looks very different.
The ISS showed that modules launched by
different rockets and built by different nations can become one working
habitat. It also showed that humans can live in microgravity for months at a
time while doctors study the consequences. Docking, resupply, spacewalking,
orbital maintenance and crew rotation became repeatable operations rather than
one-off stunts.
It also helped create the environment in
which commercial cargo and crew transportation could mature. SpaceX's Dragon
did not emerge in isolation; it grew into a transportation system partly
because NASA had a destination that needed regular service.
The Most Important Legacy May Be What Comes Next
The ISS is often described as a laboratory
in orbit. That is true, but it is only part of the story. The station is also a
prototype for a way of living that humanity has not yet taken beyond low Earth
orbit.
A lunar base will need recycling systems,
repair procedures, exercise hardware, medical protocols, reliable docking
standards and crews who know how to live inside constrained habitats for long
periods. Mars missions will need even more autonomy because help from Earth
will not arrive in hours. The communication delay alone will force crews and
onboard systems to solve more problems themselves.
That is the advantage of learning these
lessons in low Earth orbit: home is still only hours away by spacecraft, and
mission control can respond almost instantly.
That is why the ISS belongs in the same
story as human adaptation to Mars and the broader push
toward long-duration exploration. Before humanity can live comfortably on
another world, it first had to learn how surprisingly difficult it is to live
just 400 kilometers above this one.
The End of the ISS Is Not the End of Humans in Orbit
After operations wind down around 2030, the
International Space Station will begin its last mission: a controlled descent
from orbit. The solar arrays that have crossed the night sky for a generation
will be gone. The Cupola windows will no longer frame hurricanes and city
lights. A structure that hosted hundreds of people and thousands of experiments
will disappear into the atmosphere and the ocean.
It is an ending, but the better analogy may
be a handoff.
The ISS was built in an era when only
governments could realistically construct and operate a permanent human outpost
in orbit. Its successors are being designed for a different market, where
governments, companies, researchers, manufacturers and paying visitors may
share low Earth orbit.
Its deepest legacy may be simple: the ISS
made continuous human life in space feel less like a stunt and more like an
operating model.
For most of human history, every person who
ever lived was on Earth. Since November 2000, that sentence has no longer been
true.
FAQ: International Space Station in 2026
When will the International Space Station retire?
NASA and most ISS partners are planning
operations through 2030. Russia currently also plans to operate its segment
through 2030. The exact final deorbit date will depend on station condition,
logistics and readiness of the deorbit system.
Why is the ISS being retired?
The station is aging, expensive to operate
and was never designed for indefinite use. NASA also wants to move routine
low-Earth-orbit services toward commercial providers while concentrating more
resources on exploration beyond Earth orbit.
Will the ISS crash into Earth?
It will eventually re-enter Earth’s
atmosphere, but the plan is for a controlled deorbit. SpaceX is developing a
U.S. Deorbit Vehicle intended to help direct the station toward an unpopulated
ocean area.
What will replace the ISS?
There may be no single replacement. NASA is
supporting several commercial station projects, including Axiom Station and
Starlab, while Vast is targeting Haven-1 for 2027 and proposing the larger
Haven-2 architecture for the post-ISS era.
How fast does the ISS travel?
About 28,000 km/h (17,500 mph). It circles
Earth roughly every 90 minutes, giving crews about 16 sunrises and sunsets per
day.
Can tourists visit the ISS?
Private astronaut missions have already
visited the ISS through Axiom Space using SpaceX Dragon spacecraft. They
involve extensive training, medical screening and planned research or outreach,
so they are very different from buying a conventional tourist ticket.