Measurements of the natural radiation background, specifically in the upper troposphere and low stratosphere, are important in order to compare and eventually inter-calibrate different experimental set-ups, as well as to provide a reliable basis for improving the existing models related to the environmental radiation in the Earth’s atmosphere. Here, we report results from a new zero-pressure stratospheric balloon flight in the frame of the HEMERA-2 mission, obtained by measurements performed with a small portable device, (MDU)-1 Liulin. We derived the altitude profile of the atmospheric radiation in the Arctic region, namely in between Esrange Kiruna, Sweden and Rovaniemi, Finland. The preliminary analysis shows a good agreement between the measurements and Oulu models for atmospheric ionization and exposure to radiation.

Measurements of the natural radiation background with different devices and at various conditions are important from a methodological point of view in order to compare and eventually inter-calibrate different experimental sets, also to provide a reliable basis for improving the existing models for assessment of the environmental radiation in the Earth's atmosphere. Here, we report results from methodological measurements with a small portable device, namely mobile dosimetry unit (MDU)-1 Liulin, performed in different conditions in the Arctic region, including the altitude profile of the atmospheric radiation obtained during the flight of the HEMERA-2 zero-pressure balloon. A comparison with a calibrated device is also performed. It was demonstrated that the MDU-1 Liulin can provide reliable measurements of the radiation background in the Arctic atmosphere during a zero-pressure balloon flight.

Today, the near-Earth space is facing a paradigm change as the number of new spacecraft is literally sky-rocketing. Increasing numbers of small satellites threaten the sustainable use of space, as without removal, space debris will eventually make certain critical orbits unusable. A central factor affecting small spacecraft health and leading to debris is the radiation environment, which is unpredictable due to an incomplete understanding of the near-Earth radiation environment itself and its variability driven by the solar wind and outer magnetosphere. This paper presents the FORESAIL-1 nanosatellite mission, having two scientific and one technological objectives. The first scientific objective is to measure the energy and flux of energetic particle loss to the atmosphere with a representative energy and pitch angle resolution over a wide range of magnetic local times. To pave the way to novel model - in situ data comparisons, we also show preliminary results on precipitating electron fluxes obtained with the new global hybrid-Vlasov simulation Vlasiator. The second scientific objective of the FORESAIL-1 mission is to measure energetic neutral atoms (ENAs) of solar origin. The solar ENA flux has the potential to contribute importantly to the knowledge of solar eruption energy budget estimations. The technological objective is to demonstrate a satellite de-orbiting technology, and for the first time, make an orbit manoeuvre with a propellantless nanosatellite. FORESAIL-1 will demonstrate the potential for nanosatellites to make important scientific contributions as well as promote the sustainable utilisation of space by using a cost-efficient de-orbiting technology.