Post-Crew-10 Return Press Conference: Astronaut Takuya Onishi and Others Discuss ISS Science, International Cooperation, and Commercialization

While the International Space Station is heading toward the end of its operations by 2030, it continues to undergo upgrades and research. This time, we look back at Astronaut Onishi's return and introduce the post-mission press conference for Crew-10.

On August 20, 2025, the post-return press conference for SpaceX Crew-10 was held at NASA's Johnson Space Center in Houston, Texas. The speakers were NASA astronaut Anne McClain, who served as commander of the Crew Dragon "Endurance"; pilot Nicole Ayers (on her first flight); and JAXA astronaut Takuya Onishi. Roscosmos cosmonaut Kirill Peskov did not attend as he had already returned to Russia.

What emerged from the words of the three was that the ISS is a "living space station" that simultaneously tests the human body, international teams, commercial spaceflight, and connections to Earth.

148 days of flight and 146 days aboard the ISS

Crew-10 was launched from Kennedy Space Center on a Falcon 9 on March 14, 2025. The four spent 148 days in space, 146 of which were aboard the ISS. They orbited the Earth 2,368 times, covering a flight distance of approximately 62.8 million miles (about 110 million kilometers).

During their stay, they carried out the arrival and departure of Soyuz spacecraft and cargo ships, spacewalks, the hosting of Axiom Mission 4, and over 600 hours of research. On August 9, they splashed down off the coast of San Diego, California. This was the first time a NASA crewed Crew Dragon mission splashed down in the Pacific Ocean.

At the press conference, they recalled feeling the approximately 3-foot (about 90 cm) waves at splashdown were so large they joked, "Was that a tsunami?" and smiled as they described the unique sensations of returning to Earth from weightlessness.

A "living space station" continues to update until the very end

Astronaut McClain described the ISS as a "living space station."

It has been about 25 years since the ISS began operations. Its design includes technology that is over 35 years old. To use it safely for a long time, power, communications, and life support systems must be continuously inspected and updated.

On May 1, 2025, Astronauts McClain and Ayers performed a 5-hour and 44-minute spacewalk, during which they relocated communication antennas and installed mounting brackets for the future addition of the International Space Station Roll-Out Solar Array (IROSA). This work was in preparation for future upgrades. IROSA arrays are smaller than the station's traditional solar arrays, can generate more power, were first demonstrated on the orbiting laboratory in June 2017, and eight have been installed to date to boost power available for scientific research and other activities.

The ISS is not just a facility waiting for retirement; Astronaut McClain explained that it is necessary to continue updates to ensure safety until the final day of operations.

Astronaut Takuya Onishi, who did not run in space for five months

Astronaut Onishi participated in the space medicine study "Zero T2." T2 is a treadmill installed on the ISS. Astronaut Onishi did not use the T2 for about five months during his stay.

Astronauts typically use treadmills, stationary bikes, and the ARED resistance exercise device to prevent muscle and bone loss in microgravity. Zero T2 is a study to investigate how the body changes when a treadmill is not used and how it re-adapts to gravity after returning.

Immediately after returning, even standing and walking are a significant burden. At the press conference, he shared his experience of being out of breath on stairs and feeling intense fatigue even from short periods of cycling, while recovering to the point of being able to run about 10 days later.

For lunar bases or Mars missions, it may not be possible to bring all the same large exercise equipment as on the ISS. This experiment provides data to determine which exercises are truly necessary within limited time, mass, and power constraints.

Communication supports mental health even in deep space

Astronaut Onishi said that compared to his first flight in 2016, the communication environment with Earth has improved significantly. He said that being able to easily contact family and friends provided psychological support.

However, the situation changes on the Moon and Mars. Communication with the Moon has a short delay, and on Mars, it takes anywhere from a few minutes to over 20 minutes one way depending on the relative positions. The 'value of connection' gained on the ISS cannot be directly applied to deep space. It is necessary to design family support, medical support, and team operations based on the premise of delays.

Mutual trust supported the extravehicular activities

For Astronaut Ayers, this was her first extravehicular activity (EVA). For Astronaut McClain, it was her third. Inside the spacecraft, NASA astronaut Jonny Kim and others assisted with suiting up, while the ground control team monitored the entire operation.

Although there were plan changes during the EVA, both returned safely and achieved their primary objectives.

Astronaut McClain explained that EVAs require a level of trust where you can entrust your life to each other. It is not a case of the experienced astronaut unilaterally helping the newcomer. Astronaut McClain reflected that Astronaut Ayers helped her just as much, if not more.

After the hatch was closed, Astronaut Onishi helped Astronaut Ayers get out of her spacesuit, and Astronaut Ayers said it was her favorite moment of the day. An EVA is not just the work of the two people who went out into space, but the work of a single team that includes those inside the spacecraft and on the ground.

Space research leads to medicines and materials on Earth

At the press conference, the achievements that ISS research has brought to Earth were introduced.

Protein crystal growth research provided insights into the structure and size of particles suitable for injectable formulations of pembrolizumab, the active ingredient in the cancer immunotherapy drug Keytruda.

The Ring-Sheared Drop experiment investigates the formation and flow of amyloid fibrils while holding the liquid with surface tension, without letting it touch the walls of a container. Amyloids are protein aggregates associated with diseases such as Alzheimer's and Parkinson's. This research could lead not only to an understanding of disease mechanisms but also to manufacturing technologies for pharmaceuticals and materials using microgravity.

The experiment that Astronaut Onishi found particularly impressive was JAXA's Electrostatic Levitation Furnace (ELF). It uses static electricity to levitate a sample and heats it to between 2,000 and 3,000 degrees Celsius with a laser without letting it touch a container. Because the properties of materials can be measured in a state less affected by a container, data obtained from a single drop or grain in space could change medicines, materials, and manufacturing methods on Earth, and is also useful for developing new materials on the ground.

The role of space photography as shown by 'Holy Wow!'

The ISS has multiple cameras, including the Nikon Z9, which astronauts use for Earth observation, disaster recording, scientific research, and public relations.

Astronaut Ayers photographed transient luminous events such as sprites and blue jets that appear above thunderclouds.

The ISS crew called the folder where they shared particularly surprising photos 'Holy Wow!'. The photos become scientific data for short-lived natural phenomena and also serve as a means to convey a single Earth without borders.

Changes in Low Earth Orbit as Captured by Axiom Mission 4

Crew-10 welcomed the Axiom Mission 4 private human spaceflight to the ISS, which included astronauts from India, Poland, and Hungary.

As more countries and companies participate in low Earth orbit, research themes, funding, technology, and human resources will expand. At the same time, the ability to coordinate safety standards, chains of command, the handling of research results, and cultural differences will be needed more than ever.

Astronaut Onishi served as ISS Commander during his stay. He stated that the experience of managing members with different cultures and expertise will be useful for future international cooperation.

For Japan, the question is how to pass on the knowledge of international team management accumulated through providing experimental equipment and supplies, the operation of 'Kibo,' research such as ELF, and experience as an ISS Commander to commercial space stations and lunar exploration.

What 1,100 Tortillas a Year Teach Us About Life in Space

It was introduced at the press conference that over 1,100 tortillas were eaten on the ISS in 2024. It is said that 630 were delivered on the most recent supply flight.

Tortillas serve as a substitute for bread and can wrap ingredients and foods with liquid. It is also important that they produce fewer crumbs than bread or crackers. In microgravity, food crumbs can float and potentially enter eyes, equipment, or air conditioning systems.

The crew joked that they could fly tortillas like frisbees. However, since you cannot wash your hands on the ISS like you can on Earth, it is not recommended for hygiene reasons to eat them after playing with them...

In space life, food that does not produce crumbs, can be handled with one hand, and can be stored for a long time is also an important space technology.

What the ISS Leaves for the Next Era

Astronaut McClain told children aspiring to be astronauts that if they find what they love, work hard, and cooperate with their peers, they can go anywhere.

The Crew-10 press conference showed that it is not one person's ability that supports spaceflight. Exercise to protect the body, communication to stay connected with family, trust to entrust one's life, command across borders, and scientific results returned to Earth. All of that is necessary.

The greatest asset the ISS leaves for the next era is the operational culture for different countries, organizations, and experts to work safely in a dangerous environment. China is already operating its national space station 'Tiangong,' and Russia is also planning its own Russian Orbital Station (ROSS) with an eye toward after the ISS is retired. Considering the possibility that low Earth orbit may once again be divided into bases for each country, the value of the ISS, where countries including the U.S. and Russia have jointly operated a single facility while harboring political conflicts on the ground, stands out even more.

After the ISS operations end, it is expected that national space stations from China and Russia will coexist with commercial space stations that the U.S. is moving toward in low Earth orbit. The value Japan can bring to that era is the research technology cultivated through 'Kibo' and the ability to bring together international teams, return scientific results to society, and create an environment where humans can live safely for a long time.

Please see this page for more details on the scientific experiments conducted by Crew-10 during their stay on the ISS.

Mission report meetings for JAXA astronauts Onishi and Yui are scheduled to be held from August 2026 to January 2027.