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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

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

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

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

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

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

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.

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