25 Years of Space Exploration: Unlocking Earth's Potential and Beyond
For over a quarter of a century, humans have been continuously living and working aboard the International Space Station (ISS), conducting groundbreaking research that has the potential to revolutionize life on Earth and pave the way for future space exploration. From cultivating food and sequencing DNA to studying diseases and simulating Mars missions, every experiment aboard the ISS contributes to our understanding of how humans can thrive in space while advancing science and technology that benefit people worldwide.
Cancer Research from the Final Frontier
The ISS provides scientists with a unique laboratory environment unlike any other on Earth. In microgravity, cells grow in three dimensions, proteins form high-quality crystals, and biological systems reveal details hidden by gravity. These conditions offer new avenues for studying diseases and developing treatments. Astronauts and researchers have utilized the ISS to observe cancer cell growth, test drug delivery methods, and examine 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 valuable insights into the therapy's effectiveness and safety before human trials.
Protein crystal growth (PCG) is another significant area of cancer-related 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.
In addition to cancer research, studies in orbit have provided valuable insights into cardiovascular health, bone disorders, and the immune system's changes in space. This knowledge informs medicine on Earth and prepares astronauts for long missions in deep space.
Farming for the Future
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 ISS 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 successfully grown three types of lettuce, Chinese cabbage, mizuna mustard, red Russian kale, and even zinnia flowers. Astronauts have enjoyed 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 pave 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.
The First Year-Long Twin Study
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 the interplay between nature and nurture in orbit and on Earth. NASA astronaut Scott Kelly spent nearly a year aboard the ISS, 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 revealed 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. This study provided the most comprehensive molecular view to date of how the human body adapts to spaceflight, and 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.
Simulating Deep Space
The ISS, which serves as 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 new 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.
Keeping Crews Healthy in Low Earth Orbit
Staying healthy is a top priority for all NASA astronauts, but it is particularly important while living and working aboard the orbiting laboratory. The average mission lasts about six months or more, during which the human body undergoes numerous changes due to the absence of Earth's continuous gravitational pull. 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.
Sequencing the Future
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.
