25 Years of Scientific Discovery Aboard the International Space Station
November 2023 marks a significant milestone in space exploration: 25 years of continuous human presence aboard the International Space Station (ISS). Since the arrival of the first crew on November 2, 2000, the ISS has served as a platform for groundbreaking scientific research and technological innovation, enabling thousands of experiments that advance our understanding of space and benefit life on Earth. NASA, along with its international partners, has harnessed the unique microgravity environment of the ISS to explore a wide range of scientific questions and develop technologies essential for future missions to the Moon and Mars.
Over the past quarter-century, more than 4,000 experiments have been conducted aboard the ISS, leading to pivotal breakthroughs in various fields. For instance, researchers have explored how microgravity affects biological processes, leading to advancements in medical treatments for diseases like cancer and Alzheimer’s. The ISS has also been a proving ground for technologies crucial for deep space exploration, such as 3D printing tools and autonomous robotic systems that will aid astronauts in future missions. Notably, astronauts have successfully grown over 50 species of plants in space, which is vital for sustaining life during long-duration missions beyond Earth. This research not only prepares us for future exploration but also has implications for agriculture and food security on our home planet.
In addition to advancing space exploration, the ISS has become a hub for international collaboration and education, inspiring a new generation of scientists and engineers. With over 285 crew members from more than 25 countries having visited the station, it symbolizes global cooperation in space. The ISS has also played a crucial role in the burgeoning commercial space economy, enabling private companies to conduct research and develop technologies in low Earth orbit. As we celebrate 25 years of the ISS, it is clear that this remarkable laboratory has not only expanded our understanding of the universe but has also laid the groundwork for humanity’s future in space, bringing us closer to living and thriving beyond our planet.
8 Min Read
25 Years of Scientific Discovery Aboard the International Space Station
November marks 25 years of human presence aboard the International Space Station, a testament to international collaboration and human ingenuity. Since the first crew arrived on Nov. 2, 2000, NASA and its partners have conducted thousands of research investigations and technology demonstrations to advance exploration of the Moon and Mars and benefit life on Earth.
Researchers have taken advantage of the unique microgravity environment to conduct experiments impossible to replicate on Earth, transforming research across disciplines. More than 4,000 experiments have pushed the boundaries of science, sparked discoveries, and driven scientific breakthroughs.
“25 years ago, Expedition 1 became the first crew to call the International Space Station home, beginning a period of continuous human presence in space that still continues to this day,” said NASA acting administrator Sean Duffy. “This historic milestone would not have been possible without NASA and its partners, as well as every astronaut and engineer who works to keep the lights on in low Earth orbit.”
To celebrate a quarter century of innovation in microgravity, NASA is highlighting 25 scientific breakthroughs that exemplify the station’s enduring impact on science, technology, and exploration.
Building the
road to the Moon and Mars
The waxing crescent moon appears just above the Earth’s atmosphere as the International Space Station orbits the Earth.
NASA
NASA uses the space station as a proving ground to develop new systems and technologies
for missions beyond low Earth orbit
.
Navigation, communication, and
radiation shielding
technologies proven aboard the space station are being integrated into spacecraft and missions to reach the Moon and Mars.
Robotic systems, for example a
robotic surgeon
and
autonomous assistants
, will expand available medical procedures and allow astronauts to dedicate time to more crucial tasks during missions far from Earth.
Astronauts have used
recycled plastic
and
stainless steel
to 3D print tools and parts. The ability to 3D print in space lays the groundwork for on-demand repair and fabrication during future deep space missions where resupply isn’t readily available.
From the deployment of the
first wooden satellite
to
laser communications
and
self-healing quantum communications
, the space station is a proving ground for cutting-edge space technologies.
Why this matters:
Humanity’s push to the Moon and Mars begins with discoveries in low Earth orbit. From demonstrating how astronauts can live, work, and repair equipment off Earth to testing life-support systems and advanced materials, every innovation aboard the station helps to advance NASA’s Artemis and other exploration initiatives and brings humanity closer to thriving beyond our planet.
Sustaining life beyond Earth
NASA astronauts Jessica Watkins, front, and Bob Hines, back, work on XROOTS aboard the International Space Station. This experiment used the station’s Veggie facility to test soilless hydroponic and aeroponic plant growth.
NASA
As NASA prepares to return humans to the Moon through the Artemis program and push onward to Mars, sustaining life beyond Earth is more critical than ever.
Astronauts have grown more than 50 species of
plants
in space, including tomatoes, bok choi, romaine lettuce, and chili peppers.
Advanced life support systems are capable of
recycling up to 98% of water
in the U.S. segment aboard the space station, the ideal level needed for exploration missions.
Crew health data shows how space affects the
brain
, vision, balance and control, and
muscle and bone density,
guiding strategies to
maintain astronaut performance
during extended missions and improve health on Earth.
Researchers have
sequenced DNA
in orbit and are advancing techniques to enable real-time assessment of microbial life in space, which is essential to maintaining astronaut health.
Why this matters:
By growing food, recycling water, and
improving medical care
in space, NASA is paving the way for future long-duration missions to the Moon and Mars while revolutionizing agriculture and medicine back home.
Helping humanity on Earth
Pharmaceutical crystals grown aboard the International Space Station are shown after returning to Earth.
Redwire
Research aboard the orbiting laboratory not only pushes humanity farther into the cosmos but can help address complex
human health issues on the ground
. By providing a platform for long-term microgravity research, the space station fosters breakthroughs that yield direct
benefits to people on Earth
.
Research aboard the space station provides new insights to develop treatments for diseases like cancer, Alzheimer’s, Parkinson’s, and heart disease by revealing how microgravity alters
cellular functions
.
New developments in medicine
for cancer, muscular dystrophy, and neurodegenerative diseases have come from growing protein crystals in microgravity with larger, more organized structures.
High quality stem cells can be grown in greater quantities in space, helping to develop new regenerative therapies for neurological, cardiovascular, and immunological conditions.
Pioneering efforts in 3D bioprinting
, which uses cells, proteins, and nutrients as source material, have produced human tissue structures such as a
knee meniscus
and
heart tissue
, a major step toward manufacturing organs in space for transplant patients on Earth.
Researchers are using
miniaturized tissue models
to observe how space affects tissues and organ systems, offering new ways to develop and test medicines to protect astronauts on future missions and improve treatments on Earth.
Photos taken by astronauts
have supported emergency response to natural disasters, such as hurricanes, with targeted views from space.
Instruments mounted on the space station
protect critical space infrastructure and provide data on the planet’s natural patterns by measuring Earth’s resources and space weather.
Why this matters:
Microgravity research is moving us closer to manufacturing human organs in space for transplant and revealing new ways to fight cancer, heart disease, osteoporosis, neurodegenerative disease, and other serious illnesses that affect millions of people worldwide. The station also serves as an observation platform to monitor natural disasters, weather patterns, and Earth’s resources.
Understanding our universe
Artist concept of operations inside NASA’s Cold Atom Laboratory aboard the International Space Station.
NASA
The space station offers scientists an unparalleled vantage point to learn about the fundamental behavior of the
universe
. By studying cosmic phenomena typically blocked or absorbed by Earth’s atmosphere and observing physics at an atomic level, researchers can probe mysteries impossible to study from Earth.
Data from
X-ray telescopes
on the space station’s exterior have been featured in more than 700 research publications, helping to improve our understanding of
collapsing stars, black holes
, and
ripples in the fabric of space-time
.
Researchers have recorded billions of
cosmic events
, helping scientists search for antimatter and dark matter signatures in space.
Scientists have
created and studied the fifth state of matter
on the space station, allowing researchers to use quantum science to advance technology like space navigation, satellite operations, and GPS systems on Earth.
Why this matters:
Research aboard the space station is helping us unravel the deepest mysteries of our universe, from the smallest quantum particles to the most powerful cosmic explosions. Observations of collapsing stars and black holes could inspire new navigation tools using cosmic signals and expand our grasp of space-time. Studies of antimatter and dark matter bring us closer to understanding the 95% of the universe invisible to the human eye. Creating the fifth state of matter in space unlocks new quantum pathways that could transform technology on Earth and in space.
Learning new physics
This image shows a flame ignited as part of the Flame Design investigation on the International Space Station.
NASA
Physical processes
behave differently in microgravity, offering scientists a new lens for discovery.
Engineers can design more efficient fuel and life support systems for future spacecraft thanks to
studies of fluid
boiling, containment, and flow.
Analyzing gels and liquids mixed with tiny particles in space helps researchers fine-tune material compositions and has led to
new patents for consumer products
.
The discovery of cool flames in space
, a phenomenon difficult to study on Earth, has opened new frontiers in combustion science and engine design.
Why this matters:
Breakthroughs in fundamental physics aboard the space station drive innovation on Earth and advance spacecraft fuel, thermal control, plant watering, and water purification systems. Research in soft materials is improving products in medicine, household products, and renewable energy, while cool flames studies may lead to cleaner, more efficient engines.
Enabling global access to space
NASA astronaut Nichole Ayers talks on a ham radio with students from Lakeside Junior High School in Springdale, Arkansas. Ayers answered questions from the students about her experience living and working aboard the International Space Station.
NASA
Since 2000, the space station has opened doors for private companies, researchers, students, and astronauts around the world to participate in exploration and help propel humanity forward to the Moon and Mars.
The space station is a launchpad for
the commercial space economy
, enabling private astronaut missions and hosting hundreds of experiments from commercial companies, giving them the chance to strengthen their technologies through in-orbit research, manufacturing demonstrations, and innovation.
CubeSats
deployed from the space station enable students and innovators around the world to test radio antennas, small telescopes, and other scientific demonstrations in space.
More than one million students have engaged with astronauts via
ham radio events
, inspiring the next generation to participate in science, technology, engineering, and mathematics.
More than 285 crew members from more than 25 countries
have visited humanity’s longest-operating outpost in space, making it a symbol of global collaboration.
Why this matters:
The space station has enabled the space economy, where commercial research, manufacturing, and technology demonstrations are shaping a new global marketplace. NASA and its international partners have established a leadership position in low Earth orbit, creating new opportunities for industry and paving the way for exploration missions to the Moon, Mars, and beyond.
Learn more about the research aboard the International Space Station at:
www.nasa.gov/iss-science
Revisit the 20th anniversary
for more information.
Keep Exploring
Discover More Topics From NASA
International Space Station: 25 Years
November 2, 2025, marked a historic milestone: 25 years of continuous human presence aboard the International Space Station.
Latest News from Space Station Research
Space Station Research and Technology
Humans In Space
