A Quarter Century in Space: Unlocking Earth's Potential and Beyond
For over 25 years, humans have been continuously living and working aboard the International Space Station, conducting groundbreaking research that is revolutionizing life on Earth and paving the way for future exploration. From cultivating food and sequencing DNA to studying diseases and simulating Mars missions, every experiment aboard this orbiting laboratory brings us closer to understanding how humans can thrive beyond Earth while advancing science and technology that benefit people worldwide.
The space station offers scientists a unique laboratory unlike any on Earth. In microgravity, cells grow in three dimensions, proteins form higher-quality crystals, and biological systems reveal details hidden by gravity. These conditions open new avenues for studying disease and developing treatments. For instance, astronauts and researchers have observed cancer cell growth, tested drug delivery methods, and examined protein structures linked to diseases like Parkinson's and Alzheimer's.
One notable example is the Angiex Cancer Therapy study, which tested a drug designed to target blood vessels that feed tumors. In microgravity, endothelial cells survive longer and behave more like they do in the human body, providing researchers with a clearer understanding of the therapy's effectiveness and safety before human trials.
Protein crystal growth (PCG) is another critical area of cancer research. The NanoRacks-PCG Therapeutic Discovery and On-Orbit Crystals investigations have advanced research on leukemia, breast cancer, and skin cancers. Protein crystals grown in microgravity produce larger, better-organized structures, allowing scientists to determine fine structural details that guide the design of targeted treatments.
Studies in orbit have also provided valuable insights into cardiovascular health, bone disorders, and how the immune system changes in space. This knowledge informs medicine on Earth and prepares astronauts for long missions in deep space.
Feeding astronauts on long-duration missions requires more than packaged meals. It demands sustainable systems that can grow fresh food in space. The Vegetable Production System, known as Veggie, is a garden on the space station designed to test how plants grow in microgravity while adding fresh produce to the crew's diet and improving well-being in orbit.
Veggie has produced a variety of crops, including three types of lettuce, Chinese cabbage, mizuna mustard, red Russian kale, and even zinnia flowers. Astronauts have eaten space-grown lettuce, mustard greens, radishes, and chili peppers using Veggie and the Advanced Plant Habitat, a larger, more controlled growth chamber.
These plant experiments are paving the way for future lunar and Martian greenhouses by demonstrating how microgravity affects plant development, water and nutrient delivery, and microbial interactions. They also provide immediate benefits for Earth, advancing controlled-environment agriculture and vertical farming techniques that enhance food production efficiency and resilience in challenging environments.
Understanding how the human body changes in space is crucial for planning long-duration missions. NASA's Twins Study offered a unique opportunity to investigate nature vs. nurture in orbit and on Earth. NASA astronaut Scott Kelly spent nearly a year aboard the space station while his identical twin, retired astronaut Mark Kelly, remained on Earth.
By comparing the twins before, during, and after the mission, researchers examined changes at the genomic, physiological, and behavioral levels. The results showed that most changes in Scott's body returned to baseline after his return, but some persisted, such as shifts in gene expression, telomere length, and immune system responses.
The study provided the most comprehensive molecular view to date of how a human body adapts to spaceflight. Its findings may guide NASA's Human Research Program for years to come, informing countermeasures for radiation, microgravity, and isolation. The research may also have implications for health on Earth, from understanding aging and disease to exploring treatments for stress-related disorders and traumatic brain injury.
The Twins Study demonstrated the resilience of the human body in space and continues to shape the medical playbook for the Artemis campaign to the Moon and future journeys to Mars.
The space station, an analog for deep space, complements Earth-based analog research simulating the spaceflight environment. Space station observations, findings, and challenges inform the research questions and countermeasures scientists explore on Earth.
This work is currently underway through CHAPEA (Crew Health and Performance Exploration Analog), a mission where 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 under delayed communication.
NASA recently launched CHAPEA 2, with a four-person crew who began their 378-day simulated Mars mission at Johnson on October 19, 2025. Building on lessons from the first mission and decades of space station research, they will test new technologies and behavioral countermeasures that will help future explorers thrive during long-duration missions, preparing Artemis astronauts for the journey to the Moon and laying the foundation for the first human expeditions to Mars.
Maintaining health is a top priority for all NASA astronauts, especially while living and working aboard the orbiting laboratory.
Crews often spend extended periods aboard the orbiting laboratory, with the average mission lasting about six months or more. During these long-duration missions, without the continuous load of Earth's gravity, there are many changes to the human body. Proper nutrition and exercise are some of the ways these effects may be mitigated.
NASA has a dedicated team of medical physicians, psychologists, nutritionists, exercise scientists, and other specialized medical personnel who collaborate to ensure astronauts' health and fitness on the station. These teams are led by a NASA flight surgeon, who regularly monitors each crew member's health during a mission and individualizes diet and fitness routines to prioritize health and safety while in space.
Crew members are also actively involved in ongoing health and performance research to advance our understanding of long-term spaceflight's effects on the human body. This knowledge is applied to any crewed mission and will help prepare humanity to travel farther than ever before, including the Moon and Mars.
In 2016, NASA astronaut Kate Rubins made history aboard the orbital outpost as the first person to sequence DNA in space. Using a handheld device called the MinION, she analyzed DNA samples in microgravity, proving that genetic sequencing could be performed in low Earth orbit for the first time.
Her work advanced in-flight molecular diagnostics, long-duration cell culture, and molecular biology techniques such as liquid handling in microgravity. The ability to sequence DNA aboard the orbiting laboratory allows astronauts and scientists to identify microbes in real time, monitor crew health, and study how living organisms adapt to spaceflight.
The same technology now supports medical diagnostics and disease detection in remote or extreme environments on Earth. This research continues through the Genes in Space program, where students design DNA experiments that fly aboard NASA missions. Each investigation builds on Rubins' milestone, paving the way for future explorers to diagnose illness, monitor environmental health, and search for signs of life beyond Earth.
