Space Environment Data Research Articles

China's Ground‐Based Space Environment Monitoring Network—Chinese Meridian Project (CMP)

AbstractMonitoring and investigation of the solar‐terrestrial space environment is a huge challenge for humans in space age. To this end, China has established the Ground‐based Space Environment Monitoring Network, namely Chinese Meridian Project (CMP). The project comprises three major systems: the Space Environment Monitoring System, Data and Communication System, and Scientific Application System. The Space Environment Monitoring System adopts a well‐designed monitoring architecture, known as “One Chain, Three Networks, and Four Focuses,” to achieve stereoscopic and comprehensive monitoring of the entire solar‐terrestrial space. The “One‐Chain” component utilizes optical, radio, interplanetary scintillation, cosmic ray instruments to cover the causal chain of space weather disturbances from the solar surface to near‐Earth space. For the ionosphere, middle and upper atmosphere, and magnetic field, instruments are deployed along longitudes of 120° and 100°E, and latitudes of 30° and 40°N, forming the “Three Networks.” Furthermore, more powerful monitoring facilities or large‐scale instruments have been deployed in four key regions: the high‐latitude polar region, mid‐latitude region in northern China, low‐latitude region at Hainan Island, and the Tibet region. These four regions are crucial for disturbances propagation and evolution, or possess unique geographical and topographical characteristics. The Data and Communication System and Scientific Application System are designed for data collecting, processing, storage, mining, and providing user service based on data acquired by the Space Environment Monitoring System. The data obtained by CMP will be shared with the global scientific community, facilitating enhanced collaboration on space weather and space physics research.

A Multi-Satellite Space Environment Risk Prediction and Real-Time Warning System for Satellite Safety Management

In response to the need for a space security situation assessment during orbit, the multi-satellite space environmental risk prediction and early warning system is based on the detection results of the space weather payload of the Fengyun 4A and 4B satellites, as well as the prediction results of the National Space Weather Center, for the first time. By comprehensively utilizing some open-source data, it is the first time that we have achieved a 24 h advanced prediction of the space environment high-energy proton, low-energy particle, and high-energy electron risks for the safety of the Fengyun-series high-orbit satellites, and a real-time warning of satellite single-event upset, surface charging, and deep charging risks. The automation system has preliminarily achieved an intelligent space risk assessment for the safety of multiple stationary meteorological satellites, effectively improving the application efficiency of the space environmental data and the products of Fengyun-series satellites. The business status is stable in operation, and the resulting error between the predicted results of various risk indices and the measured data was less than one level. The warning accuracy was better than 90%. This article uses the system for the first time, to use Fengyun satellite data to, accurately and in a timely manner, predict and warn us about the low-energy particles and surface charging high-risk levels of the Fengyun 4A and 4B satellites during the typical space weather event on 21 April 2023, in response to the impact of complex spatial environmental factors on the safety of Fengyun-series high-orbit satellites. The construction and operation of a multi-satellite space environmental risk prediction and early warning system can provide a reference for the safety work of subsequent satellite ground system operations.

Prediction of Global Ionospheric Total Electron Content (TEC) Based on SAM‐ConvLSTM Model

AbstractThis paper first applies a prediction model based on self‐attention memory ConvLSTM (SAM‐ConvLSTM) to predict the global ionospheric total electron content (TEC) maps with up to 1 day of lead time. We choose the global ionospheric TEC maps released by the Center for Orbit Determination in Europe (CODE) as the training data set covering the period from 1999 to 2022. Besides that, we put several space environment data as additional multivariate‐features into the framework of the prediction model to enhance its forecasting ability. In order to confirm the efficiency of the proposed model, the other two prediction models based on convolutional long short‐term memory (LSTM) are used for comparison. The three models are trained and evaluated on the same data set. Results show that the proposed SAM‐ConvLSTM prediction model performs more accurately than the other two models, and more stably under space weather events. In order to assess the generalization capabilities of the proposed model amidst severe space weather occurrences, we selected the period of 22–25 April 2023, characterized by a potent geomagnetic storm, for experimental validation. Subsequently, we employed the 1‐day predicted global TEC products from the Center for Operational Products and Services (COPG) and the SAM‐ConvLSTM model to evaluate their respective forecasting prowess. The results show that the SAM‐ConvLSTM prediction model achieves lower prediction error. In one word, the ionospheric TEC prediction model proposed in this paper can establish the ionosphere TEC of spatio‐temporal data association for a long time, and realize high precision of prediction performance.

Spacecraft Test Data Integration Management Technology based on Big Data Platform

In this paper, a general test platform for spacecraft data management is designed and constructed. This paper introduces a portable software development environment based on LUA. The technology of space environment data management, comprehensive analysis, parameter correction and visual display of spacecraft is realized. The relationship between continuity, mixed dispersion, variation and indication of remote sensing data is studied. This project uses the integrated Long Short Term Memory network (LSTM) technology to detect anomalies in satellite remote sensing observation data. Give full play to the advantages of laser scanning tunneling microscope in the nonlinear field. The combination of this method and the matrix method can improve the adaptive ability of spacecraft in an operation state to better identify abnormal information in remote sensing data. Experiments show that the algorithm can significantly improve the anomaly detection rate of the system. The system can monitor the front test device and record the data. The method can be connected with the space vehicle’s central control and automatic test system. The comprehensive management of the integrated test system of space vehicles is realized.

Simulation of solar neutron flux in the Earth's atmosphere for three selected flares

We performed simulations of the solar neutron (ns) flux in the Earth's atmosphere associated with three significant flares (X17 of September 07, 2005, X1.3 of September 07, 2017 and M2.9 of September 08, 2017). The input of the simulations was calculated on the basis of ns signals detected at ground level by the Solar Neutron Telescope of Sierra Negra (SNT-SN), in Mexico, and by the FIB scintillator of the Space Environment Data Acquisition-Attached Payload on board of the International Space Station. Since ns can produce Extensive Air Showers (EAS) in the Earth's atmosphere, we used the CORSIKA code and FLUKA subroutines to simulate the particle fluxes associated with the X17, X1.3 and M2.9 flares. We studied the average longitudinal variations of particle flux and energy loss through the atmosphere to estimate the ns flux impinging on the SNT-SN. The results of the simulated interactions and multiplicities of the particles, as a function of their energy, showed that 11–13% of the ns, released by the X17 flare, could overcome the atmospheric attenuation and propagate from the top of the atmosphere to the SNT-SN (4580 m a.s.l.) without producing EAS. On the other hand, ns associated with the X1.3 and M2.9 flares were lost due to atmospheric attenuation and the production of new particles; therefore, they were not detected at ground level by the SNT- SN. The characterization of these events allowed to develop an automatic tool for the analysis of ns emissions associated with solar flares.

Relating the Solar Wind Turbulence Spectral Break at the Dissipation Range with an Upstream Spectral Bump at Planetary Bow Shocks

Abstract At scales much larger than the ion inertial scale and the gyroradius of thermal protons, the magnetohydrodynamic (MHD) theory is well equipped to describe the nature of solar wind turbulence. The turbulent spectrum itself is defined by a power law manifesting the energy cascading process. A break in the turbulence spectrum develops near-ion scales, signaling the onset of energy dissipation. The exact mechanism for the spectral break is still a matter of debate. In this work, we use the 20 Hz Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) magnetic field data during four planetary flybys at different heliocentric distances to examine the nature of the spectral break in the solar wind. We relate the spectral break frequencies of the solar wind MHD turbulence, found in the range of 0.3–0.7 Hz, with the well-known characteristic spectral bump at frequencies ∼1 Hz upstream of planetary bow shocks. Spectral breaks and spectral bumps during three planetary flybys are identified from the MESSENGER observations, with heliocentric distances in the range of 0.3–0.7 au. The MESSENGER observations are complemented by one Magnetospheric Multiscale observation made at 1 au. We find that the ratio of the spectral bump frequency to the spectral break frequency appears to be r- and B-independent. From this, we postulate that the wavenumber of the spectral break and the frequency of the spectral bump have the same dependence on the magnetic field strength ∣B∣. The implication of our work on the nature of the break scale is discussed.

High-energy gamma-rays and neutrons observed in very impulsive solar flare on 2012 June 3

AbstractAn impulsive solar flare was observed on 2012 June 3 by the Geostationary Operational Environment Satellite. In this flare, a salient feature was recognized whereby high-energy ions were accelerated to a few GeV within one minute. Associated with this flare, high-energy gamma-rays as well as high-energy neutrons were detected by the Space Environment Data Acquisition equipment onboard the International Space Station. A remarkable feature found of this event was an exceedingly high n$/$γ-ratio observed between the intensities of high-energy neutrons and gamma-rays. To understand a high n$/$γ-ratio of about 600, the interaction processes between the accelerated ions and ambient solar atmosphere were simulated for various test cases, taking into account the magnetic field of the photosphere. The simulation was extended by using the GEANT4 code and it was shown that the observed results could be reproduced under certain conditions selected for the actual interaction process. The results suggest that helium and C, N, and O ions were predominantly accelerated in this flare, and that high-energy gamma-rays and neutrons were produced by interactions between the accelerated ions and the ambient gas. As a result, a high n$/$γ-ratio was produced.

국내 우주환경 자료 보유 현황: 자기권

The Solar Space Environment Division of the Korean Society of Space Science (KSSS) has recently conducted a survey among the domestic researchers affiliated with academia, national research institutes, and for-profit institutes of how the data and models in their professional research field are produced, maintained, and utilized. The primary purpose of this survey is to increase the awareness and utilization of the space environment data and models as well as to promote constructive collaborations among the domestic and international researchers. The models and data surveyed are categorized into three sub-fields: the solar and interplanetary space, the (terrestrial) magnetosphere, and the ionosphere and upper atmosphere. The present paper reports the survey results in the “Magnetosphere” category. The survey shows that the domestically produced data in this category are far less than the data produced in other categories. This can be understood in part as follows: Magnetospheric research relies heavily on the in-situ observations but the development and operation of space-hardened satellites require a significant investment. Nevertheless, the recent publications show an increasing trend of research using the data from the ground stations and the recently launched domestic space missions. In the modeling front, there are first-principles physics models covering from the magnetospheric scale to the sub-ion scale and the models geared towards the space weather prediction. The detailed survey results can be accessed from the KSSS website (http://ksss.or.kr/).

Compression and Rendering of Space Environment Volume Data Based on Improved HVQ Algorithm

We propose an improved HVQ approach by combining two detail levels to compress space environment volumes, based on the variation characteristics including smooth variation and significantly positive correlation between variations in the same direction at two different scales. First, the space environment data is divided into 43 blocks. Then blocks are decomposed into a two-level hierarchical representation and each block is represented by a mean value and a detail vector. Finally, the detail vectors are encoded by a vector quantizer. During the vector quantization process, PCA-split is applied to compute an initial codebook, and then LBG-algorithm is conducted for codebook refinement and quantization. We take advantage of the codebook-retraining method to speed up the quantization of time series with temporal coherence. Furthermore, we employ the progressive rendering based on GPU for realtime interactive visualization. The results of our experiments prove that the algorithm proposed in this paper can significantly improve the compression rate and decoding speed without sacrificing fidelity in space environment domain.

Radiation Dose During Relativistic Electron Precipitation Events at the International Space Station

AbstractWe provide a quantitative estimate of the radiation dose during relativistic electron precipitation (REP) events at the International Space Station (ISS). To this goal, we take advantage of the data collected by the CALorimetric Electron Telescope, the Monitor of All‐sky X‐ray Image, and the Space Environment Data Acquisition equipment‐Attached Payload. The three ISS detectors offer complementary REP observations, including energy spectra and flux directional information, during a period of approximately 2.5 years, from November 2015 to March 2018. We have identified 762 REP events during this period from which we obtain the distribution of radiation dose, relevant to extravehicular activities outside the ISS.

Remote sensing of planetary space environment

Planetary space, a critical region of mass and energy exchange between the planet and the interplanetary space, is an integral part of the planetary multi-layer coupling system. Atmospheres of different compositions and plasmas of different densities and energies exist in planetary space, where mass transportation at different temporal and spatial scales and various energy deposition and dissipation processes occur. These processes are driven by the changes in the solar wind and the internal driving forces of the planet. Knowledge pertaining to the global mass and energy transportation in planetary space is essential to investigate the mass escape from the planets. Understanding the forces and physical processes that drive changes in the planetary space environment is not only beneficial to protecting the life, technical systems, and infrastructures on the Earth, but is also helpful in understanding the past and future. In this regards, the systematic and overall view of planetary space environments is necessary for planetary science. Optical remote sensing implies a measurement made by indirect or “remote” means, which relies upon either emitted, reflected, or scattered optical radiation. There are three main types of optical remote sensing technologies, namely imaging (photography), spectrograph, and spectrographic imaging. Scientific application of optical remote sensing dates back to 1906 when G. Galilei constructed the first astronomical telescope, using which he discovered the four Galilean satellites of Jupiter and the phase variation of Venus. Since then, several discoveries in planetary science have been made by means of optical remote sensing, such as the discovery of new planets and their moons, the discovery of the primary compositions of planetary atmospheres, global convection of cold plasma in Earth’s space, the discovery of planetary aurora (Earth, Mars, Jupiter, Saturn) and volcanic activity on Io, and water eruption on Enceladus. The optical remote sensing method overcomes the difficulties of capturing global views and distinguishing spatial and temporal variations in in-situ particle and field detections. Furthermore, through an overview of the history of planetary optical remote sensing, we propose a development strategy for planetary optical remote sensing, in China, based on the national deep-space exploration plan. A “Quaternity” planetary optical detection system that integrates ground-based, balloon-borne, space-based, and moon-based optical remote sensing is proposed. For example, the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS) is planning to construct a ground-based optical telescope with an aperture of ~1.5 m in Northwest China to monitor the volcanic activity on Io and to conduct other planetary observations. As the first planetary optical remote sensing project in China, the balloon-borne planetary optical remote sensing for the Scientific Experiment System in Near Space (SENSE) Program is introduced in detail. The SENSE Program is a five-year Strategic Priority Research Program of the Chinese Academy of Sciences, which began in 2018. A balloon-borne Planetary Atmospheric Spectroscopic Telescope (PAST) with an aperture of 0.8 m will be launched into the stratosphere at the height of 35–40 km to image the planetary atmosphere and plasma in the ultraviolet and visible range. The main scientific target of PAST is to comparatively study the diversity of the planetary space environment and their different drivers. Test and scientific flights are scheduled in 2021 and 2022 in Northwest China and potentially in polar regions. By using the data from PAST and in combination with other data (such as Jupiter’s auroral images from the Hubble Space Telescope, Mars’ space environment data from Mars Atmosphere and Volatile Evolution mission, and Jupiter’s space environment data from Juno mission), the couplings between planetary atmosphere and plasma will be investigated to characterize the diversity of the evolution of the planetary space environment.

A New In Situ Quasi-continuous Solar-wind Source of Molecular Water on Mercury

Abstract Radar observations of Mercury and the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft data indicate the probable existence of water ice in the permanently shadowed polar regions. Generally, water is accepted to be of exogenous origin through delivery via comets and meteoritic impact. However, a continuous water formation process that involves thermal transformation of chemically stable mineral-bound hydroxyl groups produced by implanted solar-wind protons is readily available on the surface of Mercury. At typical temperatures prevailing on Mercury’s dayside surface, H2O can be produced from reactions involving OH groups on or within the H-saturated regolith grain interfaces. Similar reactions will also occur due to micrometeorite impact events on both the dayside and nightside. Once produced, H2O is released into the exosphere and then transported and processed via Jeans escape, photodissociation, dissociative adsorption, or condensation. Water reaching cold traps will be bound over geological periods. This simple water cycle will produce a highly chemically reduced surface and can deliver significant amounts of H2O to the permanently shadowed regions of Mercury over geological time periods. The overall process is an important but hitherto unnoticed source term that will contribute to the accumulation of water in the cold traps and polar regions of Mercury.

Possible detection of solar gamma-rays by ground-level detectors in solar flares on 2011 March 7

Abstract On 2011 March 7, the Solar Neutron Telescope located at Mt. Sierra Negra, Mexico (4600 m) observed enhancements of the counting rate from 19:57 to 20:04 UT with statistical significance 6.8σ and from 20:36 to 21:03 UT with 5.8σ. One plausible physical explanation for the observation enhancements is that they were produced by solar gamma-rays. The intensities were estimated to be (0.16 ± 0.03) photons cm−2 s−1 for the first flare and (0.22 ± 0.04) photons cm−2 s−1 for the second one at the top of the atmosphere. As far as we know, this is the first report on the detection of solar gamma-rays with a ground-based detector. In association with these events, the solar neutron detector Space Environment Data Acquisition Equipment on board the International Space Station registered two solar neutrons with statistical significances of 7.3σ and 6.6σ. The Large Area Telescope on board the Fermi observatory also observed high-energy gamma-rays from this flare with a statistical significance of 6.7σ. In this paper we propose a unified model to explain the production mechanism of high-energy gamma-rays and neutrons in association with this flare.

Space Environment Data Transfer System Based on BBR Congestion Control Algorithm

Space Environment Data Transfer System Based on BBR Congestion Control Algorithm

Sino-InSpace: A Digital Simulation Platform for Virtual Space Environments

The implementation of increased space exploration missions reduces the distance between human beings and outer space. Although it is impossible for everyone to enter the remote outer space, virtual environments could provide computer-based digital spaces that we can observe, participate in, and experience. In this study, Sino-InSpace, a digital simulation platform, was developed to support the construction of virtual space environments. The input data are divided into two types, the environment element and the entity object, that are then supported by the unified time-space datum. The platform adopted the pyramid model and octree index to preprocess the geographic and space environment data, which ensured the efficiency of data loading and browsing. To describe objects perfectly, they were abstracted and modeled based on four aspects including attributes, ephemeris, geometry, and behavior. Then, the platform performed the organization of a visual scenario based on logical modeling and data modeling; in addition, it ensured smooth and flexible visual scenario displays using efficient data and rendering engines. Multilevel modes (application directly, visualization development, and scientific analysis) were designed to support multilevel applications for users from different grades and fields. Each mode provided representative case studies, which also demonstrated the capabilities of the platform for data integration, visualization, process deduction, and auxiliary analysis. Finally, a user study with human participants was conducted from multiple views (usability, user acceptance, presence, and software design). The results indicate that Sino-InSpace performs well in simulation for virtual space environments, while a virtual reality setup is beneficial for promoting the experience.

Comparison between Surface Charging Event from MICHIBIKI (QZS) Satellite and Space Environment Data from Global MHD Simulation

Space environment in geospace changes depending on the solar wind and high energy particles originated from the Sun. It is well known that the satellite anomaly sometimes occurred because of the dynamical variations of the space environment. To understand the current and future conditions of space environment, which we call 'Space Weather Forecast', is one of the quite important activities for safety and security operations of the spacecraft. On the other hand, the detailed information of spacecraft anomaly, possibly related to space disturbances, cannot be available in usual. The risk of the individual satellite depends not only on the space environment, but also on the satellite charging condition, which depend on the structure and materials of the satellite body. Therefore, it is not easy for the satellite operator to judge the risk of the satellite based on the space environment information only. To improve this situation, we start developing specialized information for the nowcasting and forecasting space environment for each satellite, and estimate the risk of satellite anomaly by combining information of space environment and that of satellite materials with a charging model. To seek this approach, the risk of satellite charging will be estimated based on the prediction of space environment using the case study of MICHIBIKI satellite, which is on the quasi-zenith orbit. As a first step, relationship among the space environment data and surface charging data obtained from MICHIBIKI satellite, and space environment data obtained from global magnetospheric MHD simulation are examined. Since the MHD simulation calculate temperature and density as single MHD fluid, an empirical relationship between simulation and observation needs to be made for obtaining the estimated temperature and density of electrons and ions. Initial comparison is introduced in this paper.

The Influence of IMF Clock Angle on Dayside Flux Transfer Events at Mercury

AbstractAnalysis of MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) data has shown for the first time that the orientation of the interplanetary magnetic field (IMF) in the magnetosheath of Mercury plays a crucial role in the formation of flux transfer events (FTEs) at the dayside magnetopause. During the first 4 Hermean years of MESSENGER's orbit around Mercury, we have identified 805 FTEs using magnetometer data. Under conditions of near‐southward IMF, at least one FTE was detected on nearly 70% of passes through the magnetopause but the observation rate during northward IMF was less than 20%. FTEs were also observed preferentially in the prenoon sector.

Interplanetary magnetic field properties and variability near Mercury's orbit

AbstractThe first extensive study of interplanetary magnetic field (IMF) characteristics and stability at Mercury is undertaken using MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) magnetometer data. Variations in IMF and solar wind conditions have a direct and rapid effect upon Mercury's highly dynamic magnetosphere; hence, understanding of the time scales over which these variations occur is crucial because they determine the duration of magnetospheric states. We characterize typical distributions of IMF field strength, clock angle, and cone angle throughout the duration of MESSENGER's mission. Clock and cone angle distributions collected during the first Earth year of the mission indicate that there was a significant north‐south asymmetry in the location of the heliospheric current sheet during this period. The stability of IMF magnitude, clock angle, cone angle, and IMF Bz polarity is quantified for the entire mission. Changes in IMF Bz polarity and magnitude are found to be less likely for higher initial field magnitudes. Stability in IMF conditions is also found to be higher at aphelion (heliocentric distance r ∼ 0.31 AU) than at perihelion (r ∼ 0.47 AU).

A statistical survey of ultralow-frequency wave power and polarization in the Hermean magnetosphere.

We present a statistical survey of ultralow‐frequency wave activity within the Hermean magnetosphere using the entire MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer data set. This study is focused upon wave activity with frequencies <0.5 Hz, typically below local ion gyrofrequencies, in order to determine if field line resonances similar to those observed in the terrestrial magnetosphere may be present. Wave activity is mapped to the magnetic equatorial plane of the magnetosphere and to magnetic latitude and local times on Mercury using the KT14 magnetic field model. Wave power mapped to the planetary surface indicates the average location of the polar cap boundary. Compressional wave power is dominant throughout most of the magnetosphere, while azimuthal wave power close to the dayside magnetopause provides evidence that interactions between the magnetosheath and the magnetopause such as the Kelvin‐Helmholtz instability may be driving wave activity. Further evidence of this is found in the average wave polarization: left‐handed polarized waves dominate the dawnside magnetosphere, while right‐handed polarized waves dominate the duskside. A possible field line resonance event is also presented, where a time‐of‐flight calculation is used to provide an estimated local plasma mass density of ∼240 amu cm−3.

Magnetic anomalies concentrated near and within Mercury's impact basins: Early mapping and interpretation

AbstractNinety‐five low‐altitude passes of MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer data from February, March, and April of 2015 have been applied to produce an approximate map of the crustal magnetic field at a constant altitude of 40 km covering latitudes of 35°–75°N and longitudes of 90°–270°E. Anomalies are concentrated near and within the Caloris impact basin. A smaller concentration occurs over and around Sobkou Planitia and an associated older large impact basin. The strongest anomalies are found within Caloris and are distributed in a semicircular arc that is roughly concentric with the basin rim. They imply the existence of a core dynamo at the time when Caloris formed (∼3.9 Gyr ago). Anomalies over high‐reflectance volcanic plains are relatively weak while anomalies over low‐reflectance material that has been reworked by impact processes are relatively strong. The latter characteristics are qualitatively consistent with the ejecta deposit model for anomaly sources.