# Space Weather Effects from Observations by Moscow University Cubesat Constellation  
[PERSON]  
1 Skobel'tsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119234 Moscow, Russia; [EMAIL_ADDRESS] (V.V.B. ); [EMAIL_ADDRESS] (A.F.I. ); [EMAIL_ADDRESS] (V.E.E. ); [EMAIL_ADDRESS] (V.V.K. ); [EMAIL_ADDRESS] (I.N.M. ); [EMAIL_ADDRESS] (V.I.O. ); [EMAIL_ADDRESS] (V.L.P. ); [EMAIL_ADDRESS] (O.Y.P. ); [EMAIL_ADDRESS] (M.I.P. ); [EMAIL_ADDRESS] (V.K.Z. ); [EMAIL_ADDRESS] (I.V.Y)  
2 Department of Physics, Lomonosov Moscow State University, 119234 Moscow, Russia  
3 Division for Aerospace Research, Novosibirsk State University, 63009 Novosibirsk, Russia; [EMAIL_ADDRESS] (V.V.P. ); [EMAIL_ADDRESS] (A.S.S.) 4 Scientific Research Laboratory of Aerospace Technique, 248018 Kaluga, Russia; [EMAIL_ADDRESS] (V.K. ); [EMAIL_ADDRESS] (A.P.P.) 5 CRES, 63009,  
radiation belts and to reveal the mechanisms of particle generation and loss. Based on these measurements' empirical models of the Earth's radiation belts were elaborated in the 1970-1980s. These models describe the spatial and energy distribution of omnidirectional proton fluxes with energies from hundreds of keV to hundreds of MeV and electrons with energies from tens of keV to \(\approx\)10 MeV in a large volume of near-Earth space, from altitudes of \(\approx\)150 km and up to geostationary and highly elliptical orbits. The most famous are the models AP8 and AE8 [1,2]; moreover, the models of the Earth's radiation belt have been developed at SINP MSU [3]. Advanced models are currently being developed, such as the AP9/AE9 model [4], based on newer experimental data. However, it is necessary to note that the models mentioned above are static. Particle flux variations are presented in them only by specifying the fluxes for the minimum and maximum solar activity epochs, while the corresponding flux values differ only for some energies by several times. At the same time, real charged particle fluxes in the near-Earth space, even near solar minima, can be characterized by very significant (more than 2 orders of magnitude) medium- and long-term variations associated with solar and geomagnetic activity, changes in the Earth's magnetic field, and the density of the upper atmosphere (see, e.g., [5,6]). Even more significant flux changes can occur during short-term magnetospheric disturbances [7, 8, 9, 10, 11]. In addition, energetic particles--ions, protons, and electrons--accelerated during powerful solar flares can enter the areas near Earth's orbit [12, 13, 14, 15, 16, 17, 18]. During such events, proton fluxes with energies of tens and hundreds of MeV can exceed the background values of galactic cosmic ray proton fluxes by 3-4 orders of magnitude or more for up to several days [19]. Such events are even less predictable than events caused by geomagnetic disturbances. One should also take into account the possibility of the appearance in low orbits of relativistic and sub-relativistic electrons accelerated during high-altitude electromagnetic discharges. Considering such effects, the electron fluxes near the geomagnetic equator at low altitudes under the radiation belts are of special interest [20,21]. Thus, real energetic charged particle fluxes at satellite orbits can differ significantly from model values. For this reason, new experimental measurements are needed that can provide real-time information about the radiation environment at the various orbits of satellite operation. At present, measurements of the energetic charged particle fluxes are carried out by a number of spacecraft. It should be noted that the NOAA geophysical observation system has been operating since the 1970s. It uses satellites of the POES series at low polar orbits [20] and GOES at geostationary orbit (simultaneously no less than two satellites in each orbit). In 2012, two NASA spacecraft, the Van Allen probes, were launched into a highly elliptical near-equatorial orbit to study the structure and characteristics of the radiation belts.