## 2 Outlook  
The Special Issue starts with several articles dealing with direct measurements of cosmic rays in flight, in different periods of the solar activity. The variability of the low-energy particle populations (mostly electrons and protons in the sub-Mev or MeV energy range) during the strong geomagnetic storm of 25-26 August 2018 is discussed in [1; 2]. In [1], the temporal and spatial distributions of the extremely/very low frequency (ELF/VLF) wave activities and the energetic electron fluxes in the ionosphere are described. This work is based on the observations by a set of detectors onboard the China Seismo-Electromagnetic Satellite (CSES-01). It is shown that the energetic electrons at energies below 1.5 MeV get strong enhancements during the whole storm time on both the day and night side. Moreover, a good correlation of the ionospheric ELF/VLF wave activities with energetic electron precipitations during the various storm evolution phases is revealed. Variations in the precipitating fluxes are also spotted in correspondence with changing geomagnetic activity. In [2], the electron rates from the High-Energy Particle Detector (HEPD-01), one of the main payloads onboard the CSES-01 satellite, are studied during the whole period of the same August storm. It has been found that the rate of electrons in the MeV energy range is characterized by a depletion during the storm's main phase and by a clear enhancement during the recovery, caused by large sub-storm activity, with the key role played by auroral processes mapped into the outer belt. A post-storm rate increase is localized at L-shells immediately above \(\sim\)3, mostly driven by non-adiabatic local acceleration--caused by possible resonant interaction with low-frequency magnetospheric waves. In the work by [PERSON] et al. [3], the inner radiation environment--better known as South Atlantic Anomaly--is studied comparing data from the aforementioned High-Energy Particle Detector with the NASA AP9 radiation model at Low-Earth Orbit. This model provides useful information on the energetic protons in the near-Earth environment, but it is still largely incomplete as to some features. The estimation reported in this analysis will serve as the starting ground for a forthcoming extensive testing and validation of other current theoretical and empirical models. Remaining in the field of direct detection, a new method that makes it possible to use an ultra-thin calorimeter for direct measurements of cosmic rays with energies of TeV and higher is shown in [4]. Due to large fluctuations in shower development, the low statistics of the analyzed events and the large size required for the calorimeter, make it almost impossible to determine the primary energy of an incoming particle. A solution to these problems is proposed on the basis of a lessening fluctuation technique, based on the assumption of the universality of the development of cascades initiated by particles of the same energy and mass. The size of the cascade and the rate of its development are analyzed and the whole method was tested using the calorimeter of the PAMELA collaboration, showing that the primary energy can be determined on the ascending branch of the cascade curve, solving the problems associated with the need to increase the thickness of the detector and with the limitation of the analyzed events. Touching then the topic of the impact of the radiation on the human activities, the study of the dose absorbed from more heavy particles by spacecraft and crews in a certain radiation environment is crucial to understand the real risks linked to space-flights. For example, in [5], the radiation dose deposited by atmospheric neutrons in human tissues is evaluated. The goal of this work is to obtain the overall dose that atmospheric neutrons (with energy from 1 to 1000 MeV) deposit in tissues of the human body, which means blood, adipose, bone and brain, as a function of both altitude and latitude. With the help of the Geant 4 software, a numerical simulation is developed.