The International Space Station (ISS) is often described as an “orbiting laboratory”, but behind that phrase lies a very concrete daily reality: a series of precise medical measurements, biological experiments, and technological demonstrations that cannot be faithfully replicated on Earth. NASA astronaut Jonny Kim, a physician and crew member of Expeditions 72/73, has just rounded off his first mission on the ISS through such work, in a period ending in early December 2025.

Kim arrived at the station on April 8, 2025, in the Russian Soyuz MS-27 spacecraft, together with cosmonauts Sergey Ryzhikov and Alexey Zubritsky. After eight months of work as a flight engineer, he returned to Earth on December 9, 2025. During his stay, he participated in experiments designed to benefit life on Earth, but also to prepare for NASA’s Artemis campaign – a program for the return of humans to the Moon, with a long-term ambition of developing technologies and protocols needed for future human missions to Mars.

Crew health under the microscope: measurements that preserve vision, bones, and general condition

One of the strongest “bridges” between the ISS and everyday medicine on Earth is the systematic monitoring of crew health. In microgravity, body fluids shift towards the head, and this shift can affect the eyes and brain. NASA describes this set of changes as Spaceflight Associated Neuro-ocular Syndrome (SANS) – a syndrome associated with spaceflight that can cause swelling of the optic nerve, changes to the retina, and other structural changes to the eye in some astronauts. The long-term outcome of these changes is still being intensively investigated, but the very fact that they can occur is serious enough for the vision and neurological status of the crew to be routinely monitored throughout the entire mission.

In practice, this means that eye exams, ultrasounds, and blood tests are regularly conducted on the ISS. During the mission, Kim performed eye ultrasounds, participated in routine checks, and collected blood samples from colleagues. Such samples provide insight into the health of cartilage and bones, cardiovascular system function, inflammatory processes, stress levels, immune system activity, and nutritional status. For the crew, these are protocols that fit into the schedule; for doctors on Earth, it is a precious set of data that helps build safer procedures for future flights, especially those without the possibility of a quick return home.

A particularly sensitive topic is the loss of bone mass. In a weightless state, the load on the skeleton is reduced, so the balance between bone “building” and “breakdown” can change faster than on Earth. Because of this, microgravity is a sort of “accelerated model” of processes similar to osteoporosis and other age-related conditions. As part of the Microgravity Associated Bone Loss-B (MABL-B) study, Kim participated in procedures studying how microgravity affects bone marrow cells and their biological signals that determine whether bone will be built or broken down. The key is to recognize “triggers” that can be blocked or redirected – to protect astronauts during long missions, and to open space on Earth for new preventive measures and therapies.

Food as technology: fresh nutrients “on demand” amidst long missions

The logistics of nutrition in space is not just a matter of the menu. Vitamins and certain nutrients can lose potency during long-term storage, and a deficiency of even one essential nutrient increases the risk of health complications. That is precisely why NASA is developing approaches for the “biomanufacturing” of nutrients during the mission. Kim worked on the BioNutrients-3 research, in which bioengineered yeasts and probiotics are used to produce fermented products like yogurt and kefir, with the possibility of enrichment with targeted nutrients.

The experiment also uses a simple but practical trick: a nutritional pH indicator in the bags changes color so the crew can visually monitor the fermentation process. On the ISS, this facilitates process control, and for future missions to the Moon and Mars, it carries an important message – part of the food system can become active production, not just consumption of pre-prepared meals. In conditions of limited resources and infrequent cargo flights, “nutrients on the spot” become a strategic advantage.

Plants in low light: more yield with less energy

Fitting into the same logic of saving energy and resources is the experiment with growing plants under lower lighting. Kim photographed dwarf tomatoes growing with an additional energy source in the form of acetate, instead of relying exclusively on photosynthesis. The research monitors plant development and gene expression, with the aim of assessing whether “secondary nutrition” can increase growth and yields, with lower consumption of electricity and total resources.

Such results could have a dual value. In space, they would help in designing systems for growing food in future habitats and spacecraft. On Earth, they could stimulate innovations in controlled growing conditions, where energy efficiency and stable yields are key – from vertical farms to specialized laboratory cultivations.

A school lesson from orbit: ham radio connection that inspires students for years

The ISS is also a global classroom. During the mission, Kim used amateur radio equipment to talk to students on Earth, as part of a program that allows schools direct contact with the crew in orbit. Students ask about sleeping in weightlessness, about the operation of experiments, about what an “ordinary day” looks like on the station, but also about the path to becoming an astronaut – from education to training and selection.

The program known as Amateur Radio on the International Space Station (ARISS) has a long history: amateur radio contacts with crews in space have lasted for decades, and ARISS has been active on the ISS since the very beginnings of the station, with regular contacts organized every year around the world. For the crew, it is a powerful reminder that behind every “measurement chart” there is an audience just entering STEM fields; for students, it is a rare opportunity to directly hear a human working in conditions that are literally above the everyday.

Data in DNA: encrypted information in a biological medium

Among the most technologically interesting demonstrations Kim conducted is the testing of the possibility of storing and transmitting data in DNA. DNA is an extremely “dense” storage of information, but the space environment brings additional challenges: radiation, temperature changes, and specific conditions for handling samples. In this experiment, encrypted information coded in DNA sequences is sequenced on the station, and then sent for analysis and decoding on Earth. The goal is to verify the stability of DNA as a medium for long-term missions, but also to assess whether such an approach could in the future reduce the mass and energy consumption of classic systems for data storage and transmission.

Robots on Earth, hands in space: remote control as preparation for surface missions

Plans for the Moon and Mars increasingly rely on a combination of human crew and robotic systems. This does not just mean “robots working alone”, but also scenarios in which astronauts from orbit or from a base control robots on the surface. Kim tested technology that enables exactly that – remote control of robots on Earth from the ISS, while collecting data on how signal latency, control ergonomics, and interface design affect precision and safety of work.

Within the framework of demonstrations linked to the Surface Avatar program, cases were also recorded in which an astronaut from the ISS controlled a robot in a simulated “Martian” landscape in Germany. Such tests help define the roles of crew and robotics in future missions: the astronaut can make decisions and manage complex actions, while the robot takes the physical risk and performs tasks in demanding terrain.

Manufacturing in weightlessness: crystals, nanospheres, and the path to medicines “in flight”

Microgravity is not just an exotic condition, but a production tool. Without gravitational currents and sedimentation, certain materials can form more evenly, and crystallization can yield structures that are harder to reproduce on Earth. Kim worked on equipment related to the Advanced Space Experiment Processor (ADSEP) and a configuration that expands the possibilities of crystallization processes. In the context of the Industrial Crystallization Cassette (ADSEP-ICC) research, the goal is, among other things, to enable the processing of a larger number of samples and the production of more uniform materials important for pharmaceuticals and advanced industry.

One of the recognizable examples in that group are gold nanospheres – tiny gold particles with optical and electronic properties and biocompatibility, which makes them interesting for drug delivery and diagnostics. On the ISS, it is being tested whether greater uniformity and potentially larger, more uniform samples can be obtained in microgravity than in conditions on Earth, where gravity and convection affect particle growth.

The next generation of medicines and industry: using proteins for models valid in space and on Earth

In the Microgravity Science Glovebox, Kim also worked on research into the behavior of highly concentrated protein liquids. Such systems are important in biotechnology and pharmacy, but are difficult to model on Earth because vessel walls and gravity introduce disturbances like sedimentation and convection. In microgravity, a “cleaner” insight into fluid dynamics is obtained, which helps in creating more precise computer models and optimizing production processes.

Falling into the same broader category is the Ring Sheared Drop (RSD) system, where surface tension holds a drop of liquid without vessel walls, between rings. Such an approach enables the study of the formation and growth of protein structures (e.g., amyloids and fibrils) without the influence of the container material, which is important both for understanding biochemical processes and for potential industrial applications – from the development of pharmaceuticals to processes that rely on precise control of fluid properties.

Earth firsthand: hurricanes, fires, and other major phenomena from the perspective of orbit

Although the ISS is most often associated with biomedicine and technology, the crew also has the role of “eyes in orbit”. On September 28, 2025, Kim photographed Hurricane Humberto from space. Such images are used to document natural disasters like hurricanes, sandstorms, and wildfires, and can help scientists and services on the ground in monitoring the development of events. The unique orbit of the ISS allows the crew to observe and photograph large areas of the planet over a relatively short time, combining local details with the “big picture” of atmospheric systems.

Who is Jonny Kim and why his profile fits the ISS mission

Kim’s professional path is an unusual combination of medicine, operational experience, and technical skill. According to official NASA data, he is a physician and U.S. Navy officer, a former Navy SEAL with over 100 combat operations and decorations such as the Silver Star and Bronze Star with “V” device. He graduated in mathematics from the University of San Diego, and then earned a doctorate in medicine at Harvard Medical School. NASA selected him in the 2017 astronaut class, and within the system, he also worked in crew support and mission roles before his own flight.

In the context of the Artemis program and preparations for deeper space, the experience of a “first mission” is particularly precious: the ISS is a dress rehearsal for what follows. On the station, it is learned how the human organism reacts to long-term stays in microgravity, how to maintain nutrition and health with limited logistics, how to develop the production of materials and potentially medicines in orbit, and how to integrate robotics and automation into crew work. Each of those lessons becomes part of a wider puzzle that will determine how safe, efficient, and sustainable future missions will be.

You can find more about scientific activities on the station and current research on the official NASA ISS Research pages and on the general section about the International Space Station.