Possible ionospheric effects of the Morelian meteoroid that passed and exploded over Mexico on 19 February 2020 (18 February 2020 local time) were estimated. The meteoroid trajectory, velocity and time of occurrence were calculated based on outdoor camera records. Modeling was used to estimate the meteoroid initial diameter, density, mass, velocity, energy and their change during its flight in the atmosphere. The ensemble of ionospheric scintillation indices calculated from the high-rate GNSS data and the filtered slant Total Electron Content data were used to reveal the presence of ionospheric disturbances generated by shock waves excited by the meteoroid flight and explosion. The first ionospheric responses to phenomena accompanying the meteoroid were detected (2.5–3.5) min after the explosion. The disturbances were attenuated quickly with distance from their source and were rarely recorded by GNSS receivers located more than 600 km from the meteoroid explosion site. The ionospheric disturbances of intermediate-scale, small-scale, shock-acoustic-wave-scale and sometimes medium-scale were revealed. The detected disturbances corresponded to the range of acoustic-gravity waves. An asymmetry of the disturbance manifestation in different directions was observed. The obtained results are in accordance with results of the observation of other meteoroids. Although the object was smaller and of less energy than other known meteoroids, it is an interesting case because, to the best of our knowledge, it isthe first known to us low-latitude meteoroid with the detected ionospheric effects.

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We describe results of a planetary defense exercise conducted during the close approach to Earth by the near-Earth asteroid (99942) Apophis during 2020 December–2021 March. The planetary defense community has been conducting observational campaigns since 2017 to test the operational readiness of the global planetary defense capabilities. These community-led global exercises were carried out with the support of NASA’s Planetary Defense Coordination Office and the International Asteroid Warning Network. The Apophis campaign is the third in our series of planetary defense exercises. The goal of this campaign was to recover, track, and characterize Apophis as a potential impactor to exercise the planetary defense system including observations, hypothetical risk assessment and risk prediction, and hazard communication. Based on the campaign results, we present lessons learned about our ability to observe and model a potential impactor. Data products derived from astrometric observations were available for inclusion in our risk assessment model almost immediately, allowing real-time updates to the impact probability calculation and possible impact locations. An early NEOWISE diameter measurement provided a significant improvement in the uncertainty on the range of hypothetical impact outcomes. The availability of different characterization methods such as photometry, spectroscopy, and radar provided robustness to our ability to assess the potential impact risk.

This paper contains the description and principles underlying the development of the velocities database of almost 500 GNSS stations with an observational duration of more than two years. They are mainly located in the territory of Eastern and Northern Europe. Various station-motion models, a multi-step technique for filtering the outliers, estimation of errors for station velocities considering different types of noise distribution as well as accounting discontinues in position time-series of stations are used when creating this base. More than 60 % of the stations are owned and constantly updated with data from various geodetic institutions of the Russian Federation. All the data is presented for the first time within one homogeneously processed database. Velocity field of the stations was used for studying the motion of the East European Craton and its parts, Baltic Shield and Russian Plate. An example of atmospheric parametres monitoring for a particularly dense network of this base around the Gulf of Finland is also given.

ISON, being an open international project that collects and interprets data about space objects for scientific analysis and spacecraft operators, includes about 40 observational sites. An involvement of two Mexican sites participating in optical observations of geostationary and highly elliptical objects as a part of the ISON project is considered. A brief description of the facilities and their observation statistics are given. Prospects for the further development of sites for monitoring near-Earth objects in Mexico are presented, including data of astronomical observing conditions from field stations.