Russia Launches Biomedical Research Satellite Bion-M No.2 | Roscosmos
Russia launched the Bion-M No.2 satellite at 17:13 UTC on Wednesday, Aug. 20, 2025, aboard a Soyuz-2-1b rocket from Site 31/6 at the Baikonur Cosmodrome. This biomedical satellite is a continuation of a Soviet and later Russian scientific program. This started with the launch of Bion 1 back in 1973.
The Bion program aims to study the effects of microgravity and space environment on living organisms, a goal that Bion-M No.2 will advance by carrying out a comprehensive study of the combined biological effects of microgravity and high levels of cosmic radiation at the systemic, organ, cellular, and molecular levels on living animals and plants aboard the spacecraft. It carries several special instruments that will register the radiation load at distinct points inside the spacecraft.
The Bion program uses spacecraft that are based on the Zenit series of reconnaissance satellites, sharing the same basic design, in particular the reentry capsule and service module. The Zenit series was itself derived from the Vostok spacecraft, which carried the first humans into space in the 1960s.
Bion-M No.2 will spend 30 days in space, in an orbit averaging between 370 and 380 km above the Earth at an inclination of 96.62°. The mission had originally been planned to use a higher orbit, with an altitude of 800 km, but in the first half of 2025 this was changed so it would be closer to the planned orbit of the proposed Russian Orbital Station (ROS). The final orbital parameters for ROS, particularly its inclination, are still under discussion.
The main passengers aboard Bion-M No.2 are 75 four-month-old male laboratory mice of the most common C57BL/6 line, delivered to Moscow from the Novosibirsk breeding station. The mice will be used for experiment MLZh-02, which sees them divided into different groups. One is a control group of ordinary mice; the others consist of “knockout mice” with genes that determine the functioning of the body’s immune system, primarily in relation to radiation, have been altered.
The NRF2 gene, which regulates the detoxification and antioxidant protection system—directly related to resistance to radiation—is the focus of this research. In one group of mice, this has been altered to be more sensitive to radiation, while in another group it has been made less sensitive.
The mice were bred specifically for this spaceflight. From birth, they have lived in groups of three to ensure they will be comfortable and avoid aggression during the flight, where they will spend enclosed in cylindrical boxes, each containing three mice.
Most of the mice will be fed a food paste that combines both dry food (based on compound feed with a full set of essential vitamins and minerals) and water. The dosing device will dispense the paste six times a day. One group will receive solid food and water separately, delivered in the form of a gel.
Most rodents have sensors implanted under their skin to register their physiological parameters: body temperature and heart rate. There will be no real-time observation or live stream from the spacecraft: scientists from the Institute of Biomedical Problems (IMBP)—part of the Russian Academy of Sciences (RAS)—will receive only short videos during the flight that will allow them to assess whether everything is safe with the mice.
The full recordings from video cameras and data from the sensors will be available only after the spacecraft returns to Earth. The planned landing of Bion-M № 2 is on September 19, 2025, on the steppe in the Orenburg region.
In addition to the data collected by their sensors, scientists plan to study the behavior of the mice. These animals were trained to perform certain actions before the flight, and will be evaluated to see if they retain these skills after the mission, in order to study how the flight has affected their memory. Alexander Andreev-Andrievsky, the head of IMBP’s Laboratory of Animal Phenotyping, expanded on this in an interview ahead of the mission. “For example, to get something pleasant, we teach mice to poke their noses into a button. Whether they will remember this after the flight is a question. In addition, we plan to develop a new skill based on the existing one. This is necessary in order to understand how animals learn after flight”.
After the flight, the experiments on mice returned from space will begin immediately. The first tests will be carried out on them on the landing site; some of the rodents will be dissected on the first day, then on the 5th, 15th, and 30th days to check their level of recovery from the spaceflight. The rest of them will stay alive to check other parameters of their health.
The 25 cylindrical containers that will house the mice are larger than those on the previous mission, Bion-M No.1, launched in 2013. Each container has a diameter of 16 cm and a height of 12 cm. An automatically changing backlight has been added, creating the illusion of day and night for the mice.
Bion-M No.2 is also carrying over 1,000 Drosophila flies to study their reproduction. This follows on from an experiment flown on the Foton-M No.4 satellite in 2014. During that mission, the flies gave birth to offspring that were then sent back into space, to the Russian segment of the ISS. This experiment showed that the descendants surpassed their parents in reproductive activity. Bion-M No.2 aims to determine whether the higher levels of radiation it will be exposed to will affect how well the flies reproduce.
Seeds from 20 species of wild and cultivated plants are being carried on Bion-M No.2, including bupleurum aureum, Schrenck’s tulip, fern leaf peony, laser, Persian poppy, pepper, tomatoes, wheat, leafy crops, thale cress, apple three seeds, and others. The mission will evaluate the germination of seeds, study the effects of space conditions on the plants, and the post–flight development of seedlings.
Various microorganisms are also flying on board the satellite: anaerobic, spore-forming microorganisms and extremophiles that scientists collected in the thermal springs of Kamchatka and in Oymyakon, the coldest permanently inhabited place on Earth. They are a part of the Meteorite experiment, studying the theory that life may have been brought to Earth from space. It consists of granite disks with various microorganisms, embedded in the shell of the lander. After the flight, they will be removed and tested to determine which microorganisms have survived.
Other experiments aboard Bion-M No.2 include in vitro cell cultures placed in special containers with a controlled environment. As part of collaboration with the Laboratory of Geochemistry of the Moon and Planets, another institute of RAS, a container with 16 test tubes with a new lunar soil analog will be tested for use in future astrobiological experiments. These will be exposed to open space radiation for a month. Another experiment will test using microorganisms to generate electrical energy aboard the satellite. Another experiment will show if the microorganisms can be used for recycling of used clothes and other waste in spaceflight.
Furthermore, a place on board has been found for two experiments designed by school students. The first one, Ecosystem in Orbit, is a small transparent plexiglass container with ants embedded in it. The second is the Russo-Belarusian scholar experiment “Into Space with your Tomato”, consisting of tomato seeds.
The Bion-M No.2 mission comes over 12 years after the previous mission, Bion-M No.1, returned to Earth in May 2013. Although it was recovered successfully, it had been subject to failures of onboard equipment and the death of some of the animals, preventing its research program from being fully completed. Scientists are hoping for a better result when the Vostok-shaped Bion-M No.2 capsule returns to Earth at the end of September 2025.
Article Credit: P. Katin/NASASpaceflight
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