Epsilon is the name given to French astronaut Sophie Adenot’s mission aboard the International Space Station (ISS). Sophie launched into space as part of the Crew-12 mission (NASA/SpaceX)  on February 13, 2026 and returned to Earth on October 8, 2026. It is the first flight of a French astronaut to the ISS since Thomas Pesquet’s Alpha mission in 2021. Sophie Adenot also became the second Frenchwoman to be part of an ISS crew, 25 years after Claudie Haigneré.

At 237 days, 5 hours, and 18 minutes, Epsilon is the longest space mission ever undertaken by a European, including both men and women.

Key milestones

• October 8, 2026: Return to Earth
• September 1, 2026: Sophie Adenot’s third spacewalk
• August 25, 2026: Sophie Adenot’s second spacewalk
• August 18, 2026: Sophie Adenot’s first spacewalk
• February 14, 2026: Sophie Adenot arrives at the International Space Station
• February 13, 2026: flight of Sophie Adenot to the ISS aboard a Crew Dragon capsule (Crew-12 mission)
• 20 June 2025: mission name and patch unveiled at the Paris Air Show, along with French experiments to which Sophie Adenot will be contributing on the ISS

Project in brief

Sophie Adenot took off early in February 2026 for a nine months mission aboard the International Space Station (ISS), where she will perform a series of scientific experiments.

Among the mission’s European experiments, a suite of French experiments will be directly monitored by the CADMOS centre for the development of microgravity applications and space operations at CNES.

Sophie will be conducting several types of experiments during her mission. Some will be aiming to gain new insights into numerous areas of investigation such as physiology, where CADMOS has an extensive legacy of expertise, while others will be testing out new technologies for future missions, in particular crewed missions to the Moon and Mars. Sophie will also be conducting an educational experiment called ChlorISS to bring space to the attention of youngsters in a fun way and encourage them to consider careers in science.

During the Epsilon mission, Sophie Adenot also conducted three spacewalks, becoming the second European woman and the first French woman to walk in space. She spent a total of 19 hours and 42 minutes working outside the Station.

Chosen by Sophie Adenot, the name Epsilon—the Greek letter ‘e’—embodies the power of small but impactful contributions. In mathematics, ε represents something small, like an astronaut’s role in the extensive collaborative effort of space exploration, while in astronomy, it’s the fifth brightest star of the Leo constellation.

Encircling the patch is a ring of small dots, symbolizing these many small contributions. The patch also features a hummingbird which, though one of Earth’s smallest birds, plays a crucial role in ecosystems, pollinating numerous plants. Three blue, white and red dots represent the flag of Sophie’s home country, France, and the Earth, Moon and Mars. Lastly, the shooting star is a poetic reminder that dreams keep us alive.

See the mission patch enlarged

CNES’s role

For CNES’s contribution to the Epsilon mission on behalf of France, the CADMOS centre for the development of microgravity applications and space operations has prepared a new suite of scientific, technological and educational experiments. Through this programme, the agency is seeking notably to further improve the ISS as a cutting-edge laboratory and give scientists the best tools to continue advancing science in space, for Earth. The aim is also to support French scientific research and technology developments geared towards exploring the solar system and deep-space crewed missions.

The French experiments to be performed during the mission are:

Contact

Epsilon mission project lead
Rémi Canton
E-mail: remi.canton at cnes.fr