near-Earth Space Research Articles

On the group velocity of whistling atmospherics

The dynamic spectrum of a whistling atmospheric is a signal of falling tone, and the group delay time of the signal as a function of frequency is formed as a result of propagation of a broadband pulse in a medium (magnetospheric plasma) with a quadratic dispersion law. In this paper, we show that for quadratic dispersion the group velocity is invariant under Galilean transformations. This means that, contrary to expectations, the group velocity is paradoxically independent of the velocity of the medium relative to the observer. A general invariance condition is found in the form of a differential equation. To explain the paradox, we introduce the concept of the dynamic spectrum of Green’s function of the path of propagation of electromagnetic waves from a pulse source (lightning discharge in the case of a whistling atmospheric) in a dispersive medium. We emphasize the importance of taking into account the motion of plasma in the experimental and theoretical study of electromagnetic wave phenomena in near-Earth space.

О групповой скорости свистящих атмосфериков

The dynamic spectrum of a whistling atmospheric is a signal of falling tone, and the group delay time of the signal as a function of frequency is formed as a result of propagation of a broadband pulse in a medium (magnetospheric plasma) with a quadratic dispersion law. In this paper, we show that for quadratic dispersion the group velocity is invariant under Galilean transformations. This means that, contrary to expectations, the group velocity is paradoxically independent of the velocity of the medium relative to the observer. A general invariance condition is found in the form of a differential equation. To explain the paradox, we introduce the concept of the dynamic spectrum of Green’s function of the path of propagation of electromagnetic waves from a pulse source (lightning discharge in the case of a whistling atmospheric) in a dispersive medium. We emphasize the importance of taking into account the motion of plasma in the experimental and theoretical study of electromagnetic wave phenomena in near-Earth space.

Cluster analysis of lightning discharges: based on Vereya-MR network data

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the VLF-LF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

Кластерный анализ молниевых разрядов по данным грозопеленгационной сети «Верея-МР»

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the VLF-LF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

МОЖЛИВОСТІ ЗАСТОСУВАННЯ СОНЯЧНОГО ВІТРИЛЬНОГО ПРИСТРОЮ ДЛЯ ВІДВЕДЕННЯ КОСМІЧНИХ ОБ’ЄКТІВ ІЗ НАПІВСИНХРОННИХ ОРБІТ

The current state of the near-Earth space environment poses a threat to spacecraft moving not only in low and geostationary but also in semi-synchronous orbits. The main methods that can be used in these orbits for space debris removal are the active method using a rocket propulsion system and the passive method using a solar sail device. The last method is of particular interest because of the low overall mass and mass characteristics of the removal system, as well as the availability of unlimited solar light radiation, which can be converted into a driving force. Solar sails are currently undergoing experimental testing in the near-Earth space, but they have not been used for medium and high orbits. Two constructive variants of solar sails construction are considered: frame and rotor. The article is devoted to the evaluation of the possibility of removing space objects from semi-synchronous orbits using a solar sail. Two variants of the removal scheme are considered: into a circular disposal orbit 200 km below the target orbit and into the dense layers of the Earth's atmosphere. A computer simulation of the removal is performed using the example of the Galileo global positioning system spacecraft with a frame-type and rotor-type solar sail. The dependence of the orbit altitude at the ending of removal on the solar sail area was obtained. The values of the solar sail area required to provide for the maneuvering and the weight of the structure were determined. It was demonstrated that the total mass of the frame-type solar sail is 9 kg (1.3% of the spacecraft mass) and that of the rotary-type solar sail is 11 kg (1.6%). As applied to disposal into dense layers of Earth's atmosphere for frame-type solar sail - 52 kg (7.4%), for rotary-type solar sail - 25.5 kg (3.6%). It follows from the obtained results that for moving to the disposal orbit 200 km below the target orbit it is more advantageous to use a frame-type solar sail, and in the dense layers of the atmosphere - the rotor type.

Method of Wavelet-Decomposition to Research Cosmic Ray Variations: Application in Space Weather

Since their discovery, cosmic rays have been an integral part of the development of fundamental physics, from the discovery of radiation coming to the Earth from outer space and the identification of high-energy particles in it, as well as new fundamental symmetries in the laws of nature, to the knowledge of residual matter and magnetic fields in interstellar space. Cosmic rays are used in a number of fundamental and applied research in solar-terrestrial physics and are important in the research of the near-Earth space processes. Cosmic ray variations observed on the Earth’s surface are an integral result of various solar, heliospheric, magnetospheric and atmospheric phenomena. The most significant changes in cosmic ray parameters are caused by coronal mass ejections and subsequent changes in the parameters of the interplanetary magnetic field and solar wind. Therefore, the study of cosmic rays makes it possible to obtain valuable information about the processes in the near-Earth space and in the Earth’s magnetosphere during disturbed periods. This article proposes a method for analyzing cosmic ray variations. It is based on the use of wavelet data decomposition operations and their combination with threshold functions. By using adaptive thresholds, the operations for detecting anomalous changes in data and for suppressing the noise were developed. Anomalies in cosmic rays can cause radiation hazard for astronauts, radio communication failures, as well as malfunctions in satellites, leading to the loss of orientation and destruction. Therefore, the task of timely diagnostics of anomalies is urgent. The paper describes the algorithms for the implementation of the method and shows their application in the space weather problem. We used data from the network of ground stations of neutron monitors. The efficiency of the method for detecting abnormal changes of different amplitudes and durations is shown. Application of the method made it possible to detect clearly and to evaluate Forbush effects in cosmic rays, which precede the onset of magnetic storms of various nature and strength.

Comparative case study of two methods to assess the eruptive potential of selected active regions

Solar eruptive events, like flares and coronal mass ejections, are characterized by the rapid release of energy that can give rise to emission of radiation across the entire electromagnetic spectrum and to an abrupt significant increase in the kinetic energy of particles. These energetic phenomena can have important effects on the space weather conditions and therefore it is necessary to understand their origin, in particular, what is the eruptive potential of an active region (AR). In these case studies, we compare two distinct methods that were used in previous works to investigate the variations of some characteristic physical parameters during the pre-flare states of flaring ARs. These methods consider: i) the magnetic flux evolution and magnetic helicity accumulation, and ii) the fractal and multi-fractal properties of flux concentrations in ARs. Our comparative analysisis based on time series of photospheric data obtained bythe Solar Dynamics Observatory between March 2011 and June 2013. We selected two distinct samples of ARs: one is distinguished by the occurrence of more energetic M- and X-class flare events, that may have a rapid effect on not just the near-Earth space, but also on the terrestrial environment; the second is characterized by no-flares or having just a few C- and B-class flares. We foundthat the two tested methods complement each other in their ability to assess the eruptive potentials of ARs and could be employed to identify ARs prone to flaring activity. Based on the presented case study, we suggest that using a combination of different methods may aid to identify more reliably the eruptive potentials of ARs and help to better understand the pre-flare states.

Activities Of The Yakutsk Geophysical Observatory (Cosmic Ray Laboratory) In 1928–1962

The relevance of the research topic is related to the generalization of the Soviet experience in formation and development of cosmophysical research in Yakutia over several decades, from the activities of weather stations to the creation of the Institute of Cosmophysical Research and Aeronomy of the Yakutsk Branch of the USSR Academy of Sciences. The formation of the network of 23 stationary meteorological and upper-air stations and the Geophysical Observatory is disclosed. The first stage of the activity of these institutions was identified as of high practical importance in the development of aviation, gold mining industry on Aldan and Amur-Yakutsk highway construction.The second stage was characteristic by innovative developments of Yakut scientists as semiconductor devices for artificial Earth satellites, cameras for shooting auroras, and an ionization camera for continuous registration of cosmic rays, that received worldwide recognition. Study of radiation situation in near-Earth space during solar flares and high-altitude thermonuclear explosions testified, that Yakutia contributed to increasing of the country's defense capability. Particular attention is paid to the activities of the station on Bolshoy Lyakhovsky Island of the Novosibirsk Islands, which served Arctic aviation flights and coastal navigation along the Northern Sea Route.

Using fireball networks to track more frequent reentries: Falcon 9 upper-stage orbit determination from video recordings

On February 16, 2021, an artificial object was recorded by the Spanish Meteor Network (SPMN) moving slowly over the Mediterranean. From the astrometric measurements, we identify this event as the reentry engine burn of a SpaceX Falcon 9 launch vehicle's upper stage. To study this event in detail, we adapted the plane intersection method for near-straight meteoroid trajectories to analyze slow and curved orbits associated with artificial objects. To corroborate our results, we approximated the orbital elements for the upper stage using four pieces of "debris" cataloged by the U.S. Government Combined Space Operations Center (CSpOC). Based on these calculations, we also estimated the possible deorbit hazard zone using the MSISE90 model atmosphere. We warn of the interference that these artificial bolides might have in fireball studies. In addition, given that artificial bolides will be probably more frequent in the future, we point out the new role that ground-based detection networks can play in the monitoring of potentially hazardous artificial objects in near-Earth space and determining the strewn field of artificial space debris.

A daytime sky analytical model of the degree of polarization for JHKs bands

The navigation technology of the near-earth space star sensors based on short-wave-infrared (SWIR, especially for JHKs bands) is a focused frontier research area. The research group has built an analytical model of daytime zenith radiance, which has a practical guiding value for optical system design, physical process simulation, and software integration development. However, it is not inadequate to consider only the spectral energy distribution of the sky background. In order to expand the approach of star identification, improve the contrast of target-to-background, and enhance the sensitivity of star detection, it is necessary to consider the polarization pattern of the daytime sky. Therefore, a sky analytical model of the degree of polarization for JHKs bands is constructed based on the Rayleigh sky model, which comprehensively takes into account the depolarization effect caused by the reflection of the earth-surface, the anisotropy of the air molecules, and the Mie scattering of the aerosol particles. The model's fitting precision is evaluated based on the error between raw data and analytical values, and the model's validity is confirmed based on the deviation between measurement data and simulation data. The results indicate that the analytical model of daytime sky degree of polarization is constructed exactly and can provide a more robust reference for the star sensor's project demonstration, performance assessment, and optimization design based on SWIR technology.

Dynamics of the Radiation Environment in the Near-Earth Space in September–November 2020 according to the Meteor-M and Electro-L Satellite Data

Dynamics of the Radiation Environment in the Near-Earth Space in September–November 2020 according to the Meteor-M and Electro-L Satellite Data

Solar Energetic Particles and Trapped Radiation in the Near-Earth Space: Space Experiments and Modelling

Solar Energetic Particles and Trapped Radiation in the Near-Earth Space: Space Experiments and Modelling

Extreme Space Weather Events during the First Cycles of Epochs with Decreased Solar Activity

The problem of the distribution of extreme and very strong magnetic storms with intensities (G5, G4) in the first cycles (12 and 24) of epochs of lowered solar activity was considered based on homogeneous series of the geomagnetic index Aa with allowance for the modern scale of the intensity of disturbances in the near-Earth space and the scenario of solar cyclicity. The significant decrease in the number of such events and active solar phenomena in the last cycle may indicate that the sunspot and flare activity in solar cycle 12 was significantly higher than that in cycle 24, but it was significantly lower than in solar cycles of the epoch of increased solar activity.

Meteorite hazard model for a space mission to Mars

Currently, for the world’s space agencies, the robotic exploration of Mars is one of the most important tasks. One of the necessary stages for the implementation of this mission is the development and addition of new information to the State standard “Meteoric substance, spatial distribution model”. Until now, the State Standard has been more detailed in comparison with the American analogue (developed by NASA) and the European one. The standard is a mandatory document in the design of spacecraft. It should be noted that modeling of meteor hazard at a distance from Earth to Mars is a complex problem, since the analysis of the meteor population in near-Earth space does not give a complete picture of the propagation of meteoroids along the Earth-Mars route. Moreover, the further the trajectory of the spacecraft from the Earth’s orbit is, the less the number of near-Earth meteorites becomes. That is, objects that have the same orbital parameters with small bodies crossing the Earth’s orbit. The only way to solve this problem is to build an interpolation regression model, which is based on measurements from the Earth’s surface and observations of space missions. For this purpose, the density of sporadic meteoroids was transformed from the space mission coordinate system to the ground one. This was done in order to analyze meteorite observations by the Mariner 4 and Pioneer 10 spacecrafts. The results of the work made it possible to obtain new data for the spatial distribution of meteoroids on the Earth-Mars path. According to a comparison of our data with the data on the density of space debris in the previous works the most safe for space flights are normalization conditions of distributions of the elements of the orbits of meteoric bodies P(Z, e, i) < 60.

Prediction of Soft Proton Intensities in the Near-Earth Space Using Machine Learning

Abstract The spatial distribution of energetic protons contributes to the understanding of magnetospheric dynamics. Based upon 17 yr of the Cluster/RAPID observations, we have derived machine-learning-based models to predict the proton intensities at energies from 28 to 962 keV in the 3D terrestrial magnetosphere at radial distances between 6 and 22 RE. We used the satellite location and indices for solar, solar wind, and geomagnetic activity as predictors. The results demonstrate that the neural network (multi-layer perceptron regressor) outperforms baseline models based on the k-nearest neighbors and historical binning on average by ∼80% and ∼33%, respectively. The average correlation between the observed and predicted data is about 56%, which is reasonable in light of the complex dynamics of fast-moving energetic protons in the magnetosphere. In addition to a quantitative analysis of the prediction results, we also investigate parameter importance in our model. The most decisive parameters for predicting proton intensities are related to the location—Z geocentric solar ecliptic direction—and the radial distance. Among the activity indices, the solar wind dynamic pressure is the most important. The results have a direct practical application, for instance, for assessing the contamination particle background in the X-ray telescopes for X-ray astronomy orbiting above the radiation belts. To foster reproducible research and to enable the community to build upon our work we publish our complete code, the data, and the weights of trained models. Further description can be found in the GitHub project at https://github.com/Tanveer81/deep_horizon.

Erratum to: Determination of the Probability of Collision of Near-Earth Space Objects Taking into Account Form and Orientation

Erratum to: Determination of the Probability of Collision of Near-Earth Space Objects Taking into Account Form and Orientation

Unusual asteroid 2020 SO: astrometric investigation of the American rocket booster that returned to near-Earth space

In the frame of this study astrometric observations of an unusual object 2020 SO - a newly discovered asteroid that turned out to be a Centaur upper-stage booster from 1960s - during its two close approaches to the Earth in December, 2020 and February, 2021 were carried out using two telescopes of Pulkovo observatory. The orbit of the object in question was determined and its future orbital evolution was modelled.

Резервное человечество

The Reserve Humanity international project is proposed for the preservation of man, as well as for the salvation and restoration of the human civilization in the event of a global catastrophe on the Earth and as an "embryo" of the space humanity. In the 21-22 centuries it is necessary to create an infrastructure in near-earth space and / or on the Moon under the auspices of the UN, to settle a reserve humanity of ~ 1000 people, taking into account technological, resource, biological and social autonomy from the earthly civilization. The concept of the project is presented. Basic notions and definitions are given. A brief substantiation and description of the reserve humanity, goals, objectives, and organization of the project has been made. A conceptual model is proposed. Conclusions are formulated.

Производство ракетно-космической техники за пределами атмосферы Земли

Further exploration of near-Earth space, the Moon and near space may require the creation of large-sized one-piece monococks as the basis for the construction of residential, production, scientifi c modules and cargo platforms. The patented in Russia method of manufacturing large-sized one-piece monococks will allow to carry out their production in open space for the fi rst time. Only work material will need to be transported from Earth.

Оцінка впливу похибок БІНС, яка побудована на MEMS-компонентах, на точність виведення ракети-носія надлегкого класу

The object of the article is the movement of an ultra-light class liquid-propellant launch vehicle in near-earth space. The subject of the research is the accuracy of launching a spacecraft by a launch vehicle. The article studies the effect of errors in the instruments of a strap-down inertial navigation system built with the use of MEMS sensors on the accuracy of launching a spacecraft into low-earth orbits with an altitude of up to 450 km for two modes of operation: with and without a satellite navigation system. Tasks: to identify the determining disturbing factors, to determine the influence of instrument errors on the trajectory tube, to determine the influence of instrument errors on the insertion accuracy, to perform a comparative analysis of the accuracy characteristics obtained for two modes of operation of the navigation system. Methods used analysis, synthesis, analogy, comparison, factor analysis, statistical modeling, statistical processing of modeling results. Results: a set of defining disturbing factors was revealed, the dependencies of the trajectory tubes on the altitude of the target orbit and flight time were obtained, the dependencies of the limiting deviations of the parameters of the spacecraft's orbit at the time of separation from the launch vehicle on the altitude of the target orbit were obtained. Conclusions. 1. It is shown that the determining perturbing factors are the zero drift of the gyroscope from launch to launch and the zero random drift of the gyroscope. 2. It was determined that the value of the trajectory tube monotonically expands on time and the height of the target orbit. Maximum deviations of the current position and absolute speed in the mode without using a satellite navigation system do not exceed 115 km and 140 m/s. For the mode using a satellite navigation system, these values do not exceed 140 m and 1.5 m/s. 3. It was revealed that the maximum deviations of the parameters of the spacecraft's orbit in the mode with the use of a satellite navigation system do not exceed 27 km in height, 1.8o in inclination, 4.5x10-4 in eccentricity, and 2.7o for the longitude of the ascending node. For the mode with a satellite navigation system - in height - 2.6 km, in inclination and longitude of the ascending node - 0.0003о, in eccentricity - 3.5x10-4. 4. Generally, the use of a satellite navigation system narrows the trajectory tube by twice, and the accuracy increases to four times, depending on the orbital parameters.