ESA project astronaut Sławosz Uznański-Wiśniewski operates one of ESA’s space freezers, known as MELFI (Minus Eighty-Degree Laboratory Freezer for ISS), during his stay aboard the International Space Station.
The European space freezers are used to store biological samples such as urine, blood and saliva at temperatures typically around –90°C. Astronauts must wear gloves when handling them due to the extreme cold.
Sławosz was launched to the ISS aboard the Dragon spacecraft as part of Axiom Mission 4 on 25 June 2025. During the 20-day Ignis mission, he carried out 13 experiments proposed by Polish companies and institutions in collaboration with ESA, as well as three additional ESA-led experiments. The experiments covered areas such as human research, materials science, biology, biotechnology and technology demonstrations.
Ax-4 is the second commercial human spaceflight for an ESA project astronaut. The Ignis mission was sponsored by the Polish government and supported by ESA, the Polish Ministry of Economic Development and Technology (MRiT), and the Polish Space Agency (POLSA).

Source: ESA