Pub Date : 2024-08-29DOI: 10.1016/j.asr.2024.08.066
Jun Chen, Liangke Huang, Si Xiong, Pituan Wu
In single-frequency precise point positioning (SF-PPP), the ionospheric delays provided by global ionosphere maps (GIMs) are in the vertical direction. Therefore, an ionospheric mapping function is applied to convert the vertical direction to the slant one. However, the performance of mapping functions (MF) applied in SF-PPP under different solar activities is unknown. Meanwhile, understanding their performance can help us better improve the accuracy of the ionospheric mapping function. For this purpose, three traditional ionospheric mapping functions, such as the standard single-layer model mapping function (SLM MF), the modified single-layer model mapping function (MSLM MF), and the Klobuchar MF, are evaluated. Additionally, the mapping function named SGG MF, which considers the effect of ionospheric gradients, is also assessed. The positioning results indicate that the SGG MF has an improvement of (50.3 %, 37.3 %), (31.7 %, 23.4 %), and (16.8 %, 13.3 %) compared with Klobuchar MF, SLM MF, and MSLM MF during the year (2014, 2021), respectively. The mean positioning errors of SLM MF, MSLM MF, and SGG MF are about (0.20 m, 0.05 m), (0.25 m, 0.10 m), and (0.30 m, 0.10 m) smaller than that of Klobuchar MF over high-/mid- latitude during the year (2014, 2021), while the values are (0.25 m, 0.20 m), (0.40 m, 0.35 m), and (0.55 m, 0.50 m) over low-latitude region. Furthermore, the correlation coefficients between positioning results and solar activities are (0.114, 0.354), (0.058, 0.324), (0.098, 0.295), and (0.235, 0.271) for Klobucahr MF, SLM MF, MSLM MF, and SGG MF during the corresponding year.
{"title":"Assessment of selected ionospheric mapping functions using SF-PPP on different solar activities","authors":"Jun Chen, Liangke Huang, Si Xiong, Pituan Wu","doi":"10.1016/j.asr.2024.08.066","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.066","url":null,"abstract":"In single-frequency precise point positioning (SF-PPP), the ionospheric delays provided by global ionosphere maps (GIMs) are in the vertical direction. Therefore, an ionospheric mapping function is applied to convert the vertical direction to the slant one. However, the performance of mapping functions (MF) applied in SF-PPP under different solar activities is unknown. Meanwhile, understanding their performance can help us better improve the accuracy of the ionospheric mapping function. For this purpose, three traditional ionospheric mapping functions, such as the standard single-layer model mapping function (SLM MF), the modified single-layer model mapping function (MSLM MF), and the Klobuchar MF, are evaluated. Additionally, the mapping function named SGG MF, which considers the effect of ionospheric gradients, is also assessed. The positioning results indicate that the SGG MF has an improvement of (50.3 %, 37.3 %), (31.7 %, 23.4 %), and (16.8 %, 13.3 %) compared with Klobuchar MF, SLM MF, and MSLM MF during the year (2014, 2021), respectively. The mean positioning errors of SLM MF, MSLM MF, and SGG MF are about (0.20 m, 0.05 m), (0.25 m, 0.10 m), and (0.30 m, 0.10 m) smaller than that of Klobuchar MF over high-/mid- latitude during the year (2014, 2021), while the values are (0.25 m, 0.20 m), (0.40 m, 0.35 m), and (0.55 m, 0.50 m) over low-latitude region. Furthermore, the correlation coefficients between positioning results and solar activities are (0.114, 0.354), (0.058, 0.324), (0.098, 0.295), and (0.235, 0.271) for Klobucahr MF, SLM MF, MSLM MF, and SGG MF during the corresponding year.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1016/j.asr.2024.08.067
Lynne Githio, Huixin Liu, Ayman A. Arafa, Ayman Mahrous
Equatorial Plasma Bubbles (EPBs) are zones characterized by fluctuations in plasma densities which form in the low-latitude ionosphere primarily during the post-sunset. They subject radio signals to amplitude and phase variabilities, affecting the functioning of technological systems that utilize the Global Navigation Satellite Systems (GNSS) signals for navigation. Thus, understanding EPB occurrence patterns and morphological features is vital for mitigating their effects. In this work, we employed two GNSS receivers and an All-Sky Imager (ASI) to conduct simultaneous observations on the morphology of EPBs over Brazil. The main objectives of the study were (1) to develop a Random Forest (RF) machine-learning model to estimate and predict the zonal drift velocities of EPBs, and (2) to compare the model predictions with actual EPB drifts inferred from the two instruments, as well as zonal neutral wind speeds obtained from the Horizontal Wind Model (HWM-14). In the model development, we utilized reliable EPB drift measurements made during geomagnetically quiet days between 2013 and 2017 in Brazil. The model predicted the velocities based on parameters including the day of the year, universal time, critical frequency of the F2 layer (foF2), solar and interplanetary indices. The correlation coefficients of 0.98 and 0.96 and RMSE values of 10.61 m/s and 10.06 m/s were obtained upon training and validation correspondingly. We evaluated the accuracy of the model in predicting EPB drifts on two geomagnetically quiet nights where an average correlation coefficient of 0.89 and an RMSE of 15.74 m/s were obtained. The predicted drifts, the zonal neutral wind velocities, and the GNSS and ASI velocity measurements were put into context for validation purposes. Overall, the velocities were comparable and ranged between ∼100 m/s and ∼30 m/s from the hours of 00 UT to 05 UT. The results confirmed the accuracy and applicability of the model, revealing the ionosphere-thermosphere coupling influence on the nocturnal propagation of EPBs under the full activation of the F region dynamo.
赤道等离子体气泡（EPBs）是以等离子体密度波动为特征的区域，主要在日落后形成于低纬度电离层。它们使无线电信号受到振幅和相位变化的影响，从而影响利用全球导航卫星系统（GNSS）信号进行导航的技术系统的运行。因此，了解 EPB 的发生模式和形态特征对于减轻其影响至关重要。在这项工作中，我们利用两台全球导航卫星系统接收器和一台全天空成像仪（ASI）对巴西上空的 EPB 形态进行了同步观测。研究的主要目标是：（1）开发一个随机森林（RF）机器学习模型来估计和预测 EPB 的带状漂移速度；（2）将模型预测结果与从两个仪器推断出的实际 EPB 漂移以及从水平风模型（HWM-14）获得的带状中性风速进行比较。在模型开发过程中，我们利用了 2013 年至 2017 年期间在巴西地磁静止日进行的可靠 EPB 漂移测量。该模型根据年月日、全球时间、F2层临界频率（foF2）、太阳指数和星际指数等参数预测了风速。训练和验证的相关系数分别为 0.98 和 0.96，均方根误差值分别为 10.61 米/秒和 10.06 米/秒。我们评估了该模型在两个地磁静夜预测 EPB 漂移的准确性，得到的平均相关系数为 0.89，均方根误差为 15.74 m/s。预测的漂移、带状中性风速、GNSS 和 ASI 速度测量结果都被放在一起进行验证。总体而言，从 00 UT 到 05 UT 的速度相当，介于 ∼100 m/s 和 ∼30 m/s 之间。结果证实了模型的准确性和适用性，揭示了电离层-热层耦合在 F 区动力完全激活的情况下对 EPB 夜间传播的影响。
{"title":"A machine learning approach for estimating the drift velocities of equatorial plasma bubbles based on All-Sky Imager and GNSS observations","authors":"Lynne Githio, Huixin Liu, Ayman A. Arafa, Ayman Mahrous","doi":"10.1016/j.asr.2024.08.067","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.067","url":null,"abstract":"Equatorial Plasma Bubbles (EPBs) are zones characterized by fluctuations in plasma densities which form in the low-latitude ionosphere primarily during the post-sunset. They subject radio signals to amplitude and phase variabilities, affecting the functioning of technological systems that utilize the Global Navigation Satellite Systems (GNSS) signals for navigation. Thus, understanding EPB occurrence patterns and morphological features is vital for mitigating their effects. In this work, we employed two GNSS receivers and an All-Sky Imager (ASI) to conduct simultaneous observations on the morphology of EPBs over Brazil. The main objectives of the study were (1) to develop a Random Forest (RF) machine-learning model to estimate and predict the zonal drift velocities of EPBs, and (2) to compare the model predictions with actual EPB drifts inferred from the two instruments, as well as zonal neutral wind speeds obtained from the Horizontal Wind Model (HWM-14). In the model development, we utilized reliable EPB drift measurements made during geomagnetically quiet days between 2013 and 2017 in Brazil. The model predicted the velocities based on parameters including the day of the year, universal time, critical frequency of the F2 layer (foF2), solar and interplanetary indices. The correlation coefficients of 0.98 and 0.96 and RMSE values of 10.61 m/s and 10.06 m/s were obtained upon training and validation correspondingly. We evaluated the accuracy of the model in predicting EPB drifts on two geomagnetically quiet nights where an average correlation coefficient of 0.89 and an RMSE of 15.74 m/s were obtained. The predicted drifts, the zonal neutral wind velocities, and the GNSS and ASI velocity measurements were put into context for validation purposes. Overall, the velocities were comparable and ranged between ∼100 m/s and ∼30 m/s from the hours of 00 UT to 05 UT. The results confirmed the accuracy and applicability of the model, revealing the ionosphere-thermosphere coupling influence on the nocturnal propagation of EPBs under the full activation of the F region dynamo.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To control the relative position and relative velocity of spacecraft formation, a time-varying nonlinear relative motion model under perturbation in an elliptical orbit is established in the port-Hamiltonian (PH) framework, and a distributed control law for spacecraft formation is developed using the consensus algorithm for parameter estimation and the passivity-based control (PBC) method based on the state-error interconnection and damping assignment (IDA) technique. First, the influence of perturbation on the potential energy and orbit parameters in the model is considered when the relative motion model is built in the PH frame, and the expression of the relative motion acceleration under perturbation is given. Second, to solve the problem that the state of the chief spacecraft cannot be directly obtained from the deputy spacecraft under distributed communication, a consensus-based parameter estimation method is introduced, the estimated parameter of the chief spacecraft is applied to the relative motion model in the PH frame, and a state error model with the estimated parameters derived from the consistency algorithm is established. Then, after the stability analysis is conducted on the desired PH system containing the estimated parameter values, the desired Hamiltonian energy function with the estimated parameters is designed according to the time-varying errors of the relative equilibrium states of the deputy spacecraft and the errors between deputy spacecraft, and the distributed control law of spacecraft formation is derived based on the state-error IDA-PBC method. Finally, the expected relative motion trajectory designed based on the TH equation is used to simulate a spacecraft formation under perturbation, and the results indicate that the spacecraft can quickly converge to the expected formation under the influence of the control law.
{"title":"Distributed control of spacecraft formation under [formula omitted] perturbation in the port-Hamiltonian framework","authors":"Wenkang Hao, Qifeng Chen, Caisheng Wei, Yuxin Liao","doi":"10.1016/j.asr.2024.08.061","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.061","url":null,"abstract":"To control the relative position and relative velocity of spacecraft formation, a time-varying nonlinear relative motion model under perturbation in an elliptical orbit is established in the port-Hamiltonian (PH) framework, and a distributed control law for spacecraft formation is developed using the consensus algorithm for parameter estimation and the passivity-based control (PBC) method based on the state-error interconnection and damping assignment (IDA) technique. First, the influence of perturbation on the potential energy and orbit parameters in the model is considered when the relative motion model is built in the PH frame, and the expression of the relative motion acceleration under perturbation is given. Second, to solve the problem that the state of the chief spacecraft cannot be directly obtained from the deputy spacecraft under distributed communication, a consensus-based parameter estimation method is introduced, the estimated parameter of the chief spacecraft is applied to the relative motion model in the PH frame, and a state error model with the estimated parameters derived from the consistency algorithm is established. Then, after the stability analysis is conducted on the desired PH system containing the estimated parameter values, the desired Hamiltonian energy function with the estimated parameters is designed according to the time-varying errors of the relative equilibrium states of the deputy spacecraft and the errors between deputy spacecraft, and the distributed control law of spacecraft formation is derived based on the state-error IDA-PBC method. Finally, the expected relative motion trajectory designed based on the TH equation is used to simulate a spacecraft formation under perturbation, and the results indicate that the spacecraft can quickly converge to the expected formation under the influence of the control law.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1016/j.asr.2024.08.059
Federico Antonello, Daniele Segneri, James Eggleston
Modeling and Simulation (M&S) tools have become indispensable for the comprehensive design, operations, and maintenance of products in the space industry. An example is the European Space Agency (ESA), which relies heavily on M&S throughout the entire lifecycle of a spacecraft. However, their use in operational settings poses significant challenges, mainly attributable to () the harsh, uncontrollable, and often unforeseen environmental conditions; () the dramatic changes in operating conditions throughout a spacecraft’s lifespan, often beyond the intended designed-for lifetime; and () the presence of epistemic and aleatoric uncertainty. This results in unavoidable discrepancies between the numerical simulations and real measurements, limiting their use for delicate operational tasks. To address those challenges, we present a Bayesian framework for simultaneous calibration of M&S tools, reduction of the model discrepancy, and quantification of the process and model uncertainties. The approach leverages the Kennedy and O’Hagan (KOH) calibration, tailored for a multi-objective problem. Its effectiveness is shown by its application to flying Earth observation spacecraft data and the operational simulation models.
{"title":"A Bayesian framework for in-flight calibration and discrepancy reduction of spacecraft operational simulation models","authors":"Federico Antonello, Daniele Segneri, James Eggleston","doi":"10.1016/j.asr.2024.08.059","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.059","url":null,"abstract":"Modeling and Simulation (M&S) tools have become indispensable for the comprehensive design, operations, and maintenance of products in the space industry. An example is the European Space Agency (ESA), which relies heavily on M&S throughout the entire lifecycle of a spacecraft. However, their use in operational settings poses significant challenges, mainly attributable to () the harsh, uncontrollable, and often unforeseen environmental conditions; () the dramatic changes in operating conditions throughout a spacecraft’s lifespan, often beyond the intended designed-for lifetime; and () the presence of epistemic and aleatoric uncertainty. This results in unavoidable discrepancies between the numerical simulations and real measurements, limiting their use for delicate operational tasks. To address those challenges, we present a Bayesian framework for simultaneous calibration of M&S tools, reduction of the model discrepancy, and quantification of the process and model uncertainties. The approach leverages the Kennedy and O’Hagan (KOH) calibration, tailored for a multi-objective problem. Its effectiveness is shown by its application to flying Earth observation spacecraft data and the operational simulation models.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1016/j.asr.2024.08.058
Joseph I. Minow, Vania K. Jordanova, David Pitchford, Natalia Y. Ganushkina, Yihua Zheng, Gian Luca Delzanno, Insoo Jun, Wousik Kim
The natural space environment exerts many harmful (called “space weather”) effects on spacecraft in orbit around the Earth as well as probes to other planets. The main hazards among these are surface charging, internal charging, single event effects, and total dose. Specifically, the ∼ keV electron population can have substantial impacts on spacecraft by causing spacecraft surface charging and electrostatic discharges (ESD). This hazard continues to be of great relevance today due to the continual evolution of the human use of space in terms of the number of satellites launched, the technologies they use and the design / manufacturing / test techniques used to build them. In the past, the majority of operating spacecraft were in Geosynchronous Earth Orbit (GEO), nowadays the Low-Earth orbit (LEO) satellite population dominates and the number of Non-Geostationary Satellite Orbit (NGSO) constellations increases; these new constellations are likely to increase the technical risks associated with harmful space weather conditions. This paper summarizes the state of art for surface charging including background of the phenomenon, data sources for characterizing charging on spacecraft, modeling of the space weather environment, surface charging modeling tools, and charging indices and metrics. Future directions and both near- and long-term recommendations are also provided.
{"title":"ISWAT spacecraft surface charging review","authors":"Joseph I. Minow, Vania K. Jordanova, David Pitchford, Natalia Y. Ganushkina, Yihua Zheng, Gian Luca Delzanno, Insoo Jun, Wousik Kim","doi":"10.1016/j.asr.2024.08.058","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.058","url":null,"abstract":"The natural space environment exerts many harmful (called “space weather”) effects on spacecraft in orbit around the Earth as well as probes to other planets. The main hazards among these are surface charging, internal charging, single event effects, and total dose. Specifically, the ∼ keV electron population can have substantial impacts on spacecraft by causing spacecraft surface charging and electrostatic discharges (ESD). This hazard continues to be of great relevance today due to the continual evolution of the human use of space in terms of the number of satellites launched, the technologies they use and the design / manufacturing / test techniques used to build them. In the past, the majority of operating spacecraft were in Geosynchronous Earth Orbit (GEO), nowadays the Low-Earth orbit (LEO) satellite population dominates and the number of Non-Geostationary Satellite Orbit (NGSO) constellations increases; these new constellations are likely to increase the technical risks associated with harmful space weather conditions. This paper summarizes the state of art for surface charging including background of the phenomenon, data sources for characterizing charging on spacecraft, modeling of the space weather environment, surface charging modeling tools, and charging indices and metrics. Future directions and both near- and long-term recommendations are also provided.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-24DOI: 10.1016/j.asr.2024.08.060
M.A. Malkov, I.V. Moskalenko, P.H. Diamond, M. Cao
Recent measurements of primary and secondary CR spectra, their arrival directions, and our improved knowledge of the magnetic field geometry around the heliosphere allow us to set a bound on the distance beyond which a puzzling 10-TeV “bump” and certain related spectral features originate. The sharpness of the spectral breaks associated with the bump, the abrupt change of the CR intensity across the local magnetic equator ( pitch angle), and the similarity between the primary and secondary CR spectral patterns point to a local reacceleration of the bump particles out of the background CRs. We argue that, owing to a steep preexisting CR spectrum, a nearby shock may generate such a bump by boosting particle rigidity by a mere factor of 1.5 in the range below 50 TV. Reaccelerated particles below 0.5 TV are convected with the interstellar medium flow and do not reach the Sun. The particles above this rigidity then form the bump. This single universal process is responsible for the observed spectral features of all CR nuclei, primary and secondary, in the rigidity range below 100 TV. We propose that one viable candidate is the system of shocks associated with Eridani star at 3.2 pc of the Sun, which is well aligned with the direction of the local magnetic field. Other shocks, such as old supernova shells, may produce a similar effect. We provide a simple formula that reproduces We show how our formalism predicts helium, boron, carbon, oxygen, and iron spectra, for which accurate data in GV-TV range exist. Our model thus unifies all the CR spectral features observed below 50 TV.
最近对初级和次级 CR 光谱及其到达方向的测量，以及我们对日光层周围磁场几何形状的进一步了解，使我们能够确定一个令人费解的 10-TeV "凸起 "和某些相关光谱特征的起源距离。与 "凸起 "相关的光谱断裂的尖锐性、横跨本地磁赤道（俯仰角）的 CR 强度的突然变化，以及主 CR 和次 CR 光谱模式之间的相似性，都表明 "凸起 "粒子从背景 CR 中脱离后，在本地进行了再加速。我们认为，由于先前存在陡峭的CR频谱，附近的冲击可能会在50TV以下的范围内将粒子的刚度提高1.5倍，从而产生这种撞击。低于 0.5 TV 的再加速粒子与星际介质流对流，不会到达太阳。高于这个刚度的粒子就形成了凹凸。在刚度低于 100 TV 的范围内，所有 CR 核（原生核和次生核）的光谱特征都是由这一单一的普遍过程造成的。我们认为一个可行的候选者是与太阳 3.2 pc 处的 Eridani 星相关的冲击系统，它与当地磁场的方向完全一致。其他冲击，如老的超新星外壳，也可能产生类似的效应。我们展示了我们的形式主义是如何预测氦、硼、碳、氧和铁光谱的，这些光谱在 GV-TV 范围内都有精确的数据。因此，我们的模型统一了在 50 TV 以下观测到的所有 CR 光谱特征。
{"title":"Very local impact on the spectrum of cosmic-ray nuclei below 100 TeV","authors":"M.A. Malkov, I.V. Moskalenko, P.H. Diamond, M. Cao","doi":"10.1016/j.asr.2024.08.060","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.060","url":null,"abstract":"Recent measurements of primary and secondary CR spectra, their arrival directions, and our improved knowledge of the magnetic field geometry around the heliosphere allow us to set a bound on the distance beyond which a puzzling 10-TeV “bump” and certain related spectral features originate. The sharpness of the spectral breaks associated with the bump, the abrupt change of the CR intensity across the local magnetic equator ( pitch angle), and the similarity between the primary and secondary CR spectral patterns point to a local reacceleration of the bump particles out of the background CRs. We argue that, owing to a steep preexisting CR spectrum, a nearby shock may generate such a bump by boosting particle rigidity by a mere factor of 1.5 in the range below 50 TV. Reaccelerated particles below 0.5 TV are convected with the interstellar medium flow and do not reach the Sun. The particles above this rigidity then form the bump. This single universal process is responsible for the observed spectral features of all CR nuclei, primary and secondary, in the rigidity range below 100 TV. We propose that one viable candidate is the system of shocks associated with Eridani star at 3.2 pc of the Sun, which is well aligned with the direction of the local magnetic field. Other shocks, such as old supernova shells, may produce a similar effect. We provide a simple formula that reproduces We show how our formalism predicts helium, boron, carbon, oxygen, and iron spectra, for which accurate data in GV-TV range exist. Our model thus unifies all the CR spectral features observed below 50 TV.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1016/j.asr.2024.08.050
Carynelisa Haspel, Yoav Yair
Transient luminous events (TLEs) is the collective name given to mesospheric electrical breakdown phenomena occurring in conjunction with strong lightning discharges in tropospheric thunderstorms. They include elves, sprites, halos, and jets, and are characterized by short lived optical emissions, mostly of red (665 nm) and blue (337 nm) wavelengths. Sprites are caused by the brief quasi-electrostatic field induced in the mesosphere, mostly after the removal of the upper positive charge of the thundercloud by a +CG, and they have been recorded above most of the lightning activity centers on Earth. In wintertime, there are just a few areas where lightning occurs, and of those, sprites have been observed over the Sea of Japan, the British Channel, and the Mediterranean Sea. Unlike their summer counterparts, winter thunderstorms tend to have weaker updrafts and as a result, reduced vertical dimensions and compact charge structures, whose positive and negative centers are located at lower altitudes. These storms are often susceptible to significant wind shear and as a result may exhibit a tilted dipole charge structure and a lateral offset of the upper positive charge relative to the main negative charge. We present results of numerical simulations using a three-dimensional explicit formulation of the mesospheric quasi-electrostatic electrical field following a lightning discharge from a typical mid-latitude winter thunderstorm exhibiting tilt due to wind shear and evaluate the regions of possible sprite inception. Our results show, as numerous observations suggest, that sprites can be shifted a large distance from the location of the parent +CG in the direction of the shear and will occur over a larger region compared with non-sheared storms.
{"title":"Numerical simulations of the region of possible sprite inception in the mesosphere above winter thunderstorms under wind shear","authors":"Carynelisa Haspel, Yoav Yair","doi":"10.1016/j.asr.2024.08.050","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.050","url":null,"abstract":"Transient luminous events (TLEs) is the collective name given to mesospheric electrical breakdown phenomena occurring in conjunction with strong lightning discharges in tropospheric thunderstorms. They include elves, sprites, halos, and jets, and are characterized by short lived optical emissions, mostly of red (665 nm) and blue (337 nm) wavelengths. Sprites are caused by the brief quasi-electrostatic field induced in the mesosphere, mostly after the removal of the upper positive charge of the thundercloud by a +CG, and they have been recorded above most of the lightning activity centers on Earth. In wintertime, there are just a few areas where lightning occurs, and of those, sprites have been observed over the Sea of Japan, the British Channel, and the Mediterranean Sea. Unlike their summer counterparts, winter thunderstorms tend to have weaker updrafts and as a result, reduced vertical dimensions and compact charge structures, whose positive and negative centers are located at lower altitudes. These storms are often susceptible to significant wind shear and as a result may exhibit a tilted dipole charge structure and a lateral offset of the upper positive charge relative to the main negative charge. We present results of numerical simulations using a three-dimensional explicit formulation of the mesospheric quasi-electrostatic electrical field following a lightning discharge from a typical mid-latitude winter thunderstorm exhibiting tilt due to wind shear and evaluate the regions of possible sprite inception. Our results show, as numerous observations suggest, that sprites can be shifted a large distance from the location of the parent +CG in the direction of the shear and will occur over a larger region compared with non-sheared storms.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1016/j.asr.2024.08.055
Manu H. Nair, Mini C. Rai, Mithun Poozhiyil, Steve Eckersley, Steven Kay, Joaquin Estremera
Space telescopes have been instrumental in enlightening our understanding of the universe, from the iconic Hubble Space Telescope to specialized instruments like Chandra and Kepler. Pushing the frontiers of cosmic exploration, the future of space exploration hinges on modular Large Aperture Space Telescopes (LAST), much larger than the recently launched 6.5 m James Webb Space Telescope, necessitating robotic assembly in orbit. This paper introduces a paradigm shift in astronomical observation by featuring robotic in-orbit assembly of a large aperture space telescope. This review paper starts by tracing the evolution of telescopes and presents a comprehensive overview of the state-of-the-art space telescopes. This paper then reinforces the need for LAST to address the constant clamour for higher-resolution astronomy. While current semi-autonomous robotic manipulators operate from the International Space Station, their limited walking capabilities constrain their workspace, making them unsuitable for the LAST mission. This paper presents a detailed trade-off analysis of the challenges associated with the in-orbit assembly of LAST using candidate robots to understand the technological gaps. Further, the evolution of space robotic manipulators is presented, highlighting design features, advantages, and drawbacks for in-orbit spacecraft servicing and assembly missions. To tackle design and modelling challenges for robotic systems in space, amidst the various perturbations in the extreme space environment, linear and non-linear control systems necessary for achieving ultra-high precision performance are also discussed. This paper advances the walking space manipulator technology by introducing the next generation of walking space manipulators – the End-Over-End Walking Robot (E-Walker). The dexterous and modular design of the E-Walker makes it an ideal candidate for missions involving assembly, manufacturing, servicing, and maintenance.
从标志性的哈勃太空望远镜到钱德拉和开普勒等专用仪器，太空望远镜在启迪我们对宇宙的认识方面发挥了重要作用。太空探索的未来取决于模块化大孔径太空望远镜（LAST），它比最近发射的 6.5 米詹姆斯-韦伯太空望远镜大得多，需要在轨道上用机器人组装。本文以机器人在轨组装大口径太空望远镜为特色，介绍了天文观测模式的转变。这篇综述论文首先追溯了望远镜的发展历程，并全面概述了最先进的空间望远镜。然后，本文强调了 LAST 的必要性，以满足人们对更高分辨率天文学的不断需求。虽然目前的半自主机器人操纵器在国际空间站上运行，但其有限的行走能力限制了其工作空间，使其不适合 LAST 任务。本文对使用候选机器人进行 LAST 在轨组装所面临的挑战进行了详细的权衡分析，以了解技术差距。此外，本文还介绍了空间机器人机械手的演变，突出了在轨航天器维修和组装任务的设计特点、优势和缺点。为了应对空间机器人系统在极端空间环境中的各种扰动所带来的设计和建模挑战，还讨论了实现超高精度性能所需的线性和非线性控制系统。本文介绍了下一代太空行走机械手--端对端行走机械手（E-Walker），从而推动了太空行走机械手技术的发展。E-Walker 的灵巧性和模块化设计使其成为涉及装配、制造、维修和维护任务的理想候选者。
{"title":"Robotic technologies for in-orbit assembly of a large aperture space telescope: A review","authors":"Manu H. Nair, Mini C. Rai, Mithun Poozhiyil, Steve Eckersley, Steven Kay, Joaquin Estremera","doi":"10.1016/j.asr.2024.08.055","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.055","url":null,"abstract":"Space telescopes have been instrumental in enlightening our understanding of the universe, from the iconic Hubble Space Telescope to specialized instruments like Chandra and Kepler. Pushing the frontiers of cosmic exploration, the future of space exploration hinges on modular Large Aperture Space Telescopes (LAST), much larger than the recently launched 6.5 m James Webb Space Telescope, necessitating robotic assembly in orbit. This paper introduces a paradigm shift in astronomical observation by featuring robotic in-orbit assembly of a large aperture space telescope. This review paper starts by tracing the evolution of telescopes and presents a comprehensive overview of the state-of-the-art space telescopes. This paper then reinforces the need for LAST to address the constant clamour for higher-resolution astronomy. While current semi-autonomous robotic manipulators operate from the International Space Station, their limited walking capabilities constrain their workspace, making them unsuitable for the LAST mission. This paper presents a detailed trade-off analysis of the challenges associated with the in-orbit assembly of LAST using candidate robots to understand the technological gaps. Further, the evolution of space robotic manipulators is presented, highlighting design features, advantages, and drawbacks for in-orbit spacecraft servicing and assembly missions. To tackle design and modelling challenges for robotic systems in space, amidst the various perturbations in the extreme space environment, linear and non-linear control systems necessary for achieving ultra-high precision performance are also discussed. This paper advances the walking space manipulator technology by introducing the next generation of walking space manipulators – the End-Over-End Walking Robot (E-Walker). The dexterous and modular design of the E-Walker makes it an ideal candidate for missions involving assembly, manufacturing, servicing, and maintenance.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In spacecraft mission planning and operation, the attitude determination and control subsystem (ADCS) of a satellite provides information about the orientation of the satellite in the inertial reference frame. Furthermore, this subsystem produces the control actions required to adjust the orientation of the satellite, especially in the low-Earth orbit (LEO) regime. This paper focuses on the satellite’s three-axis attitude control problem within the context of active and passive control, which includes detumbling control, pointing control, magnetic control, and attitude stabilization after solar panel wing deployment using magnetorquers as the primary actuators. The objective is to stabilize and reduce the angular rate while orienting the satellite to the desired attitude. The proposed satellite attitude control system (ACS) strategies are designed, developed, characterized, and verified. These strategies encompass the B-dot control algorithm for detumbling control along with pointing control and attitude stabilization after solar panel wing deployment. hardware-in-the-loop simulation (HiLs) tests are conducted to assess the performance of the satellite magnetorquer-based ACS in the presence of noise. These tests involve a relative Earth’s magnetic field (EMF) generator in conjunction with SGP-4-based satellite orbital propagator high-level control software. Additionally, cascade proportional-integral-derivative (PID) and state-dependent Riccati equation (SDRE) controllers are implemented to generate sufficient torque using three-axis magnetorquers on a frictionless air-bearing platform. The platform is balanced to closely simulate the dynamic motion of a spacecraft in space. The testing includes a single initial condition and three inertia conditions for stabilization after solar panel wing deployment. Finally, the effectiveness of the cosimulation as a primary experiment through an integrated HiLs process is validated. This comprehensive approach confirms the control system’s performance and its ability to meet mission requirements.
{"title":"Characterization and verification of the optimal feedback gain of a satellite magnetorquer-based attitude control system","authors":"Thanayuth Panyalert, Shariff Manuthasna, Jormpon Chaisakulsurin, Tanawish Masri, Kritsada Palee, Pakawat Prasit, Peerapong Torteeka, Poom Konghuayrob","doi":"10.1016/j.asr.2024.08.047","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.047","url":null,"abstract":"In spacecraft mission planning and operation, the attitude determination and control subsystem (ADCS) of a satellite provides information about the orientation of the satellite in the inertial reference frame. Furthermore, this subsystem produces the control actions required to adjust the orientation of the satellite, especially in the low-Earth orbit (LEO) regime. This paper focuses on the satellite’s three-axis attitude control problem within the context of active and passive control, which includes detumbling control, pointing control, magnetic control, and attitude stabilization after solar panel wing deployment using magnetorquers as the primary actuators. The objective is to stabilize and reduce the angular rate while orienting the satellite to the desired attitude. The proposed satellite attitude control system (ACS) strategies are designed, developed, characterized, and verified. These strategies encompass the B-dot control algorithm for detumbling control along with pointing control and attitude stabilization after solar panel wing deployment. hardware-in-the-loop simulation (HiLs) tests are conducted to assess the performance of the satellite magnetorquer-based ACS in the presence of noise. These tests involve a relative Earth’s magnetic field (EMF) generator in conjunction with SGP-4-based satellite orbital propagator high-level control software. Additionally, cascade proportional-integral-derivative (PID) and state-dependent Riccati equation (SDRE) controllers are implemented to generate sufficient torque using three-axis magnetorquers on a frictionless air-bearing platform. The platform is balanced to closely simulate the dynamic motion of a spacecraft in space. The testing includes a single initial condition and three inertia conditions for stabilization after solar panel wing deployment. Finally, the effectiveness of the cosimulation as a primary experiment through an integrated HiLs process is validated. This comprehensive approach confirms the control system’s performance and its ability to meet mission requirements.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1016/j.asr.2024.08.056
Shoaib Ahmed Khan, Zou Tao, Shah Fahad, Muhammad Salman, Mustafa Tahir, Anwar Ali
The advent of CubeSats, compact satellites with a standardized form factor, has disrupted traditional space research paradigms, fostering innovation and collaboration across academic institutions and industries. Following deployment, CubeSats typically employ magnetorquer rods to initiate the detumbling sequence, gradually reducing the angular velocity before transferring control to reaction wheels for complete spin neutralization. However, this conventional approach entails a substantial spacecraft space requirement, necessitating an alternative and disruptive methodology. Furthermore, considering that approximately 50% of Attitude Determination and Control Subsystems (ADCS) failures are attributed to faults related to the moving parts in reaction wheels, strategies are taken into consideration to address a worst-case scenario of reaction wheels failure. This paper introduces a disruptive approach that uses diverse geometries and a non-unity track width ratio in PCB-integrated magnetorquers with reaction wheels for comprehensive control. We demonstrate the effectiveness of various coil configurations through a series of extensive simulations and establish a systematic framework to select optimal hybrid designs tailored to specific mission requirements.
{"title":"Reliable attitude control integrating reaction wheels and embedded asymmetric magnetorquers for detumbling CubeSats","authors":"Shoaib Ahmed Khan, Zou Tao, Shah Fahad, Muhammad Salman, Mustafa Tahir, Anwar Ali","doi":"10.1016/j.asr.2024.08.056","DOIUrl":"https://doi.org/10.1016/j.asr.2024.08.056","url":null,"abstract":"The advent of CubeSats, compact satellites with a standardized form factor, has disrupted traditional space research paradigms, fostering innovation and collaboration across academic institutions and industries. Following deployment, CubeSats typically employ magnetorquer rods to initiate the detumbling sequence, gradually reducing the angular velocity before transferring control to reaction wheels for complete spin neutralization. However, this conventional approach entails a substantial spacecraft space requirement, necessitating an alternative and disruptive methodology. Furthermore, considering that approximately 50% of Attitude Determination and Control Subsystems (ADCS) failures are attributed to faults related to the moving parts in reaction wheels, strategies are taken into consideration to address a worst-case scenario of reaction wheels failure. This paper introduces a disruptive approach that uses diverse geometries and a non-unity track width ratio in PCB-integrated magnetorquers with reaction wheels for comprehensive control. We demonstrate the effectiveness of various coil configurations through a series of extensive simulations and establish a systematic framework to select optimal hybrid designs tailored to specific mission requirements.","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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