Radiation isn't as scary as it's made out to be: Scientists have released preliminary data on dosimetric monitoring on a biosatellite.

Almost a sensation – the radiation accumulated during the month-long flight of the Bion-M-2 spacecraft was found to be equal to that accumulated in the habitation module of the ISS! Scientists from the Institute of Biomedical Problems of the Russian Academy of Sciences have released preliminary data on dosimetric monitoring of the biosatellite, which spent a month in polar orbit around Earth with an inclination of 96.6 degrees, a new inclination for living objects.

Amidst escalating debate about the inclination to deploy our new Russian orbital station in the near future (some believed the high-latitude inclination approved by Roscosmos last year would pose a radiation hazard to cosmonauts), scientists at the Institute of Biomedical Problems of the Russian Academy of Sciences (RAS) have received the first results from the radiometric sensors returned by the Biona-M-2 descent module. The results were not as dire as predicted.

As a reminder, Bion-M orbited Earth from August 20 to September 19, 2025, at a polar inclination of 96.6 degrees, approximately the same orbit to which the first module of the future Russian orbital station (ROS) is planned to be launched in 2028. This orbit was chosen by Russian scientists to study radiation levels, which in high-latitude orbit are close to those encountered by our cosmonauts during their flight to the Moon and on the moon itself.

Mice, flies, ants, plants, and microorganisms orbited in polar orbit for a full month. Their return was eagerly awaited, allowing for the first conclusions to be drawn regarding the possibility of human travel to the vicinity of Selena.

In fact, scientists received the very first data indicating that almost 90 percent of the mice had survived and were doing well immediately, on the day of the descent module's landing. As Oleg Orlov, Director of the Institute of Biomedical Problems of the Russian Academy of Sciences and Academician of the Russian Academy of Sciences, explained immediately afterward, several mice were injured in fights with their fellow cosmonauts, possibly over food, which is considered natural given their generally aggressive nature.

While the animals were being taken to laboratories and are being actively studied, specialists from the Radiation Research Department at the Institute of Biomedical Problems of the Russian Academy of Sciences have already analyzed the radiation sensors installed inside and outside the Biona-M's living compartment.

"We've been measuring radiation doses on the ISS for a long time," department head Vyacheslav Shurshakov told MK. "When sending the biosatellite into a new polar orbit, we decided to compare the radiation on it with the dose on the ISS, for example, in the cosmonaut's cabin, where a dosimeter hangs on the wall. It turned out that over the 30-day flight, the dosimeter installed inside the Bion-M, which flew in an orbit inclined at 96.6 degrees, showed exactly the same accumulated radiation level as over the same period on the ISS, inclined at 51.6 degrees."

– What dose did the mice receive?

– 0.3 milligray (mGy) per day. Multiplying this by 30 days yields 9 milligray. This is the same amount as cosmonauts aboard the ISS receive per month. It's also worth noting that there were no solar-proton events during the Bion-M-2 mission.

– What about the data from the external radiation sensor?

Here, we obtained several values ​​depending on the thickness of the protective coatings for our sensors (astronauts, after all, don't go on spacewalks without protective suits). External radiation was 3-4 times higher than for the ISS for sensors under thin protection (corresponding to the helmet visor and the soft parts of the spacesuit a cosmonaut wears during extravehicular activity on the ISS). As for the thicker protective layer (similar to a cuirass—the thick part of the spacesuit surrounding the chest and back), it protected our sensors as well as a real spacesuit would protect a real cosmonaut during a spacewalk on the ISS.

– So, can we conclude that the radiation level in polar orbit is not as high as expected?

"In all fairness, we probably won't even have to enhance the protection of our spacesuits for work on the outer surface of the ROS. After all, what does a radiation level three to four times higher mean? Today, a cosmonaut on the ISS receives the same dose during six hours of spacewalking as during a day inside the ISS. This means that for the ROS, such a spacewalk would result in three to four daily doses to less-protected parts of the body. Some may have several such spacewalks during a single space shift. But keep in mind that in polar orbit, the increase was recorded, roughly speaking, only in certain parts of the spacesuit."

– Did this surprise you very much as a specialist?

"From a radiation standpoint, there's nothing sensational about it. There are various models that describe this radiation, and what we calculated before the flight is roughly what we got."

Published in the Moskovsky Komsomolets newspaper, No. 29620, October 3, 2025

Newspaper headline: Radiation is not as scary as it is painted