1. On the Probable Change of the Status of the Current Unusual Failure of 11-Year Solar Cyclicity from Local to Global

   • V. I. Kozlov

   OriginalPaper 05 April 2021 Pages: 71 - 79

   

2. Development of the Project for Reconstruction of the Havana Radio Astronomy Station as Part of the Russian Solar and Space Weather Services

   • V. M. Bogod
   • A. A. Storozhenko
   • Sierra Pablo

   OriginalPaper 05 April 2021 Pages: 80 - 88

   

3. Postvolcanic Aerosols: Measurements of Altitude and Particle Sizes with Twilight-Sky Polarimetry

   • O. S. Ugolnikov
   • I. A. Maslov

   OriginalPaper Open access 05 April 2021 Pages: 89 - 95

   

4. Lower Ionosphere of the Arctic in June 2015 during a Strong Magnetic Storm and Solar X-Ray Flares According to Eclipsing Radiosonde Data on GPS–Formosat Intersatellite Paths

   • S. S. Matyugov
   • O. I. Yakovlev
   • A. A. Pavel’ev

   OriginalPaper 05 April 2021 Pages: 96 - 103

   

5. Development of the Common Classification of Hazard Events in Near-Earth Space

   • E. A. Pavlova
   • M. V. Zakhvatkin
   • L. V. Elenin

   OriginalPaper 05 April 2021 Pages: 104 - 111

   

6. Investigation of Steady-State Motion of an Artificial Earth Satellite in the Uniaxial Magnetic Orientation Mode

   • A. I. Ignatov
   • V. V. Sazonov

   OriginalPaper 05 April 2021 Pages: 112 - 125

   

7. Reconstruction of Rotational Motion of the Progress Spacecraft in the Mode of One-Axis Solar Orientation According to Solar Array Current Measurements

   • M. Yu. Belyaev
   • T. V. Matveeva
   • V. V. Sazonov

   OriginalPaper 05 April 2021 Pages: 126 - 141