A Quarter-Century in Orbit Shows How Space Science Is Shaping Life on Earth and Future Exploration

For more than 25 years, humans have lived and worked continuously aboard the International Space Station (ISS), turning it into one of the most productive scientific laboratories ever created. Since the first crew arrived in November 2000, the orbiting outpost has supported thousands of experiments that go far beyond space exploration. Research conducted in microgravity has reshaped medicine, agriculture, human health studies, and technology on Earth, while also laying the groundwork for future missions to the Moon, Mars, and beyond.

The ISS offers scientists something Earth simply cannot: a sustained microgravity environment. Without gravity constantly pulling things down, cells grow differently, fluids behave in unexpected ways, and biological systems reveal details that remain hidden on Earth. These unique conditions have allowed researchers to study disease, develop treatments, and test technologies in ways that would otherwise be impossible.

Why Microgravity Changes Everything

One of the most important advantages of the space station is how cells and proteins behave in microgravity. On Earth, gravity flattens cells and interferes with how molecules assemble. In orbit, cells grow in three dimensions, closely mimicking how they behave inside the human body. Proteins form larger and more precisely ordered crystals, making it easier to study their structure.

This has had major implications for medical research, especially cancer studies. Scientists have used the ISS to observe how cancer cells grow, spread, and respond to treatment. Drug delivery systems can also be tested more accurately in space, where cell behavior better reflects real human physiology.

One notable example is the Angiex Cancer Therapy investigation. This study focused on a drug designed to target the blood vessels that feed tumors. In microgravity, endothelial cells survive longer and act more like they do in the human body. That gave researchers a clearer picture of how the therapy works and whether it could be safe and effective before moving into human clinical trials.

Protein Crystals and Precision Medicine

Another major area of ISS research involves protein crystal growth (PCG). Experiments such as NanoRacks-PCG Therapeutic Discovery and On-Orbit Crystals have supported research into leukemia, breast cancer, and skin cancers. Protein crystals grown in microgravity are larger and better organized than those grown on Earth, allowing scientists to identify extremely fine structural details.

These details matter. Understanding protein structures at high resolution helps researchers design targeted drugs that fit precisely into disease-causing molecules. The benefits of this research extend far beyond cancer, influencing treatments for neurological conditions like Parkinson’s and Alzheimer’s disease as well.

Studying the Human Body in Space

Living in space for months at a time places unusual stress on the human body. Without gravity, astronauts experience changes in bone density, muscle mass, cardiovascular function, immune response, and vision. Studying these changes has become one of the ISS’s most important roles.

A landmark project in this area was NASA’s Twins Study. Astronaut Scott Kelly spent nearly a year aboard the space station, while his identical twin brother, Mark Kelly, remained on Earth. By comparing the twins before, during, and after the mission, researchers were able to study the effects of spaceflight at genomic, physiological, and behavioral levels.

The results showed that many changes in Scott Kelly’s body returned to normal after he came back to Earth. However, some effects persisted, including shifts in gene expression, changes in telomere length, and alterations in immune system activity. This study provided the most detailed molecular look yet at how the human body adapts to long-duration spaceflight, and its findings continue to guide NASA’s Human Research Program.

The implications go beyond space travel. Insights from the Twins Study may help scientists better understand aging, immune disorders, stress-related conditions, and traumatic brain injury on Earth.

Growing Food in Orbit

Long-duration missions cannot rely entirely on packaged food. Fresh produce is important for nutrition, mental health, and crew morale. To address this, NASA developed the Vegetable Production System, commonly known as Veggie.

Veggie is a small garden aboard the ISS designed to test how plants grow in microgravity. So far, astronauts have grown and eaten lettuce, mustard greens, radishes, and chili peppers, and have also cultivated zinnia flowers. Experiments have included crops such as Chinese cabbage, mizuna mustard, and red Russian kale.

In addition to Veggie, the Advanced Plant Habitat provides a more controlled environment, allowing scientists to closely study how plants respond to microgravity, lighting, water delivery, and nutrients. These studies are essential for future lunar and Martian greenhouses, where astronauts will need reliable food production systems.

Back on Earth, this research supports advances in controlled-environment agriculture, including vertical farming and hydroponic systems that make food production more efficient and resilient in harsh environments.

DNA Sequencing in Space

In 2016, NASA astronaut Kate Rubins achieved a historic milestone by becoming the first person to sequence DNA in space. Using a handheld device called the MinION, she proved that genetic sequencing could be performed in microgravity.

This breakthrough opened the door to real-time microbial monitoring, in-flight medical diagnostics, and advanced molecular biology experiments aboard the ISS. Astronauts can now identify microbes on the station, monitor crew health, and study how living organisms adapt to spaceflight.

The technology has also found applications on Earth, particularly in remote or extreme environments where traditional laboratory equipment is impractical. The work continues through the Genes in Space program, which allows students to design DNA experiments that fly on NASA missions.

Simulating Mars on Earth

While the ISS itself acts as a stand-in for deep-space missions, NASA also conducts Earth-based analog studies informed by space station research. One of the most ambitious is CHAPEA, the Crew Health and Performance Exploration Analog.

In this project, volunteers live and work inside a 1,700-square-foot, 3D-printed Mars habitat for about a year. The first CHAPEA crew completed 378 days in isolation in 2024, testing strategies for maintaining health, growing food, and sustaining morale with delayed communication.

NASA has since launched CHAPEA 2, with a four-person crew beginning their own 378-day mission on October 19, 2025, at Johnson Space Center. These simulations build directly on decades of ISS research and are designed to prepare astronauts for the challenges of future Artemis missions and eventual human expeditions to Mars.

Keeping Astronauts Healthy

Astronaut health is continuously monitored during long-duration missions, which typically last six months or more. Without gravity, the body undergoes many changes, making nutrition and exercise critical countermeasures.

NASA supports crews with a team of flight surgeons, psychologists, nutritionists, exercise scientists, and medical specialists. Each astronaut follows an individualized health plan, and all crew members contribute to ongoing research that helps refine medical strategies for future missions.

A Global Legacy of Science

After a quarter-century in orbit, the International Space Station stands as a powerful example of international collaboration and scientific achievement. It has transformed space into a living laboratory, delivered tangible benefits to people on Earth, and provided essential knowledge for humanity’s next giant leaps into the solar system.

As research continues, the ISS remains a bridge between Earth and deep space, proving that long-term human presence beyond our planet is not only possible, but scientifically invaluable.

Research reference:
NASA Twins Study – Integrated Omics Analysis of Long-Duration Spaceflight
https://www.nature.com/articles/s41586-019-0931-8