Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant paramete...Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.展开更多
The most important all-round progress in China's Space Science in recent years is the official go-ahead of Strategic Priority Program(SPP) on Space Science in 2011,which marks China's space science has entered...The most important all-round progress in China's Space Science in recent years is the official go-ahead of Strategic Priority Program(SPP) on Space Science in 2011,which marks China's space science has entered a new stage.SPP on Space Science includes 4 satellites(DAMPE,SJ-10,QUESS and HXMT),the Intensive Study of Future Space Science Missions,and the Advanced Research of Space Science Missions and Payloads.It is expected that the innovative breakthroughs will be achieved,and the great leaps of related high-technology will be driven through both independent space science missions and international cooperation.The implementation of the SPP on Space Science will enable the rapid development of China's space science endeavor,and contribute to the progress of human civilization.展开更多
The Strategic Priority Program on Space Science in 2011–2017(hereafter referred to as SPP Ⅰ),which officially went ahead in 2011, marks that a new chapter of Chinese space endeavor has been opened.The 4 satellites, ...The Strategic Priority Program on Space Science in 2011–2017(hereafter referred to as SPP Ⅰ),which officially went ahead in 2011, marks that a new chapter of Chinese space endeavor has been opened.The 4 satellites, Wukong/DAMPE, SJ-10, Mozi/QUESS and Insight/HXMT, has been achieving promising scientific results since their launch, e.g., Wukong directly detected a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons. To enable the sustainable development of China's space science endeavor,the Strategic Priority Program Ⅱ on Space Science(hereafter referred to as SPP Ⅱ) was officially approved in late 2017. SPP Ⅱ includes 4 satellites—EP, ASO-S, SMILE and GECAM, Intensive Study of Future Space Science Missions, Advanced Research of Space Science Missions and Payloads, Space Science Mission Concept Research, and Data Analysis Research. Dedicated to exploring the unknown, the program is aiming to address scientific questions such as the origin and evolution of the universe and life, search for extraterrestrial life,and the impact of the Sun and the solar system on Earth and human development. Chinese space science community is committed to contributing to the progress of human civilization.展开更多
The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientif...The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientific achievements have been made by the first phase of the Program(SPPⅠ),while SPPⅡhas been currently being implemented.The future development of space science needs urgent top-level planning and advanced layout to clarify the overall goal and investment portfolio from 2025 to 2030.We will briefly introduce the initiative and possible space science missions of SPPⅢ,including the preparatory work which already started in July 2021.Following the effective administrative tradition since SPPⅠ,National Space Science Center(NSSC,CAS)is responsible for the whole procedure,including soliciting,assessment,and implementation of SPPⅢ.Brief information on the 13 candidate missions will be described,including missions in the fields of astronomy&astrophysics,exoplanets,heliophysics and planetary&Earth science,respectively.展开更多
Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explo...Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explorer(DAMPE),Quantum Experiments at Space Scale(QUESS),Advanced Space-based Solar Observatory(ASO-S),Einstein Probe(EP),and significant scientific outcomes have been achieved.In order to plan the future space science missions in China,CAS has organized the Chinese space science community to conduct medium and long-term development strategy studies,and summarized the major scientific frontiers of space science as“One Black,Two Dark,Three Origins and Five Characterizations”.Five main scientific themes have been identified for China’s future breakthroughs,including the Extreme Universe,Space-Time Ripples,the Panoramic View of the Sun and Earth,the Habitable Planets,and Biological&Physical Science in Space.Space science satellite missions to be implemented before 2030 are proposed accordingly.展开更多
In May 2018,the second phase of the Strategic Priority Program on Space Science(SPP II)was officially approved by the Chinese Academy of Sciences,in view of the significant scientific achievements of the first phase o...In May 2018,the second phase of the Strategic Priority Program on Space Science(SPP II)was officially approved by the Chinese Academy of Sciences,in view of the significant scientific achievements of the first phase of the Strategic Priority Program on Space Science(SPP I)which includes 4 space science missions:the Dark Matter Particle Explorer(DAMPE),ShiJian-10(SJ-10),Quantum Experiments at Space Scale(QUESS)and Hard X-ray Modulation Telescope(HXMT).Aiming to address fundamental scientific questions,SPP II focuses on two major themes:How the universe and life originate and evolve and What is the relationship between the solar system and human beings.In areas that Chinese scientists have advantages,new space science missions including Graviational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),the Advanced space-based Solar Observatory(ASO-S),the Einstein Probe(EP),and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)have been approved in the framework of SPP II.This paper presents the research highlights of the SPP I,introduces the recent progress of SPP II,and puts forward the prospects for future development.展开更多
Strategic Priority Research Program on Space Science has gained remarkable achievements. Space Environment Prediction Center(SEPC) affiliated with the National Space Science Center(NSSC) has been providing space weath...Strategic Priority Research Program on Space Science has gained remarkable achievements. Space Environment Prediction Center(SEPC) affiliated with the National Space Science Center(NSSC) has been providing space weather services and helps secure space missions. Presently, SEPC is capable to offer a variety of space weather services covering many phases of space science missions including planning, design, launch,and orbital operation. The service packages consist of space weather forecasts, warnings, and effect analysis that can be utilized to avoid potential space weather hazard or reduce the damage caused by space storms,space radiation exposure for example. Extensive solar storms that occurred over Chinese Ghost Festival(CGF)in September 2017 led to a large enhancement of the solar energetic particle flux at 1 AU, which affected the near Earth radiation environment and brought great threat to orbiting satellites. Based on the space weather service by SEPC, satellite ground support groups collaborating with the space Tracking, Telemetering and Command system(TT&C) team were able to take immediate measures to react to the CGF solar storm event.展开更多
Implementing the flyby to Near-Earth Asteroids (NEAs) with the potential impact risks to the Earth allows for obtaining detailed physical parameters, thereby supporting the high-precision orbit prediction and planetar...Implementing the flyby to Near-Earth Asteroids (NEAs) with the potential impact risks to the Earth allows for obtaining detailed physical parameters, thereby supporting the high-precision orbit prediction and planetary defense strategy. Different from those conducted asteroid flyby missions, in the 12th China Trajectory Optimization Competition (CTOC-12), a NEAs flyby trajectory design problem using reusable probes that depart from a Lunar Distant Retrograde Orbit (DRO) station in the cislunar space was released. The objective was flyby to as many NEAs as possible using up to 20 probes within a total of 10 years. The ∑ team proposed a solution that can explore 47 NEAs using 11 probes, ranking the first in the competition. In this paper, the methods and results from the winning team are introduced, including mission analysis and preliminary design, and low-energy transfer trajectory optimization. In particular, a round-trip trajectory is divided into three phases: deep space transfer, indirect transfer between the Earth to DRO, and DRO phasing and rendezvous. With the combination of global optimization and local optimization algorithms, the required velocity increments to change the orbital planes are effectively reduced, thus increasing the number of the explored NEAs. The final solution of our team is presented and the results are compared with those of the top three teams. The competition demonstrates that the regularization of flyby missions from the cislunar space to explore NEAs with the potential impact risks to the Earth is the feasible and promising.展开更多
The National Space Science Center of the Chinese Academy of Sciences(NSSC,CAS),as the leading institute responsible for the overall management of scientific satellite missions in China,is China’s gateway to space sci...The National Space Science Center of the Chinese Academy of Sciences(NSSC,CAS),as the leading institute responsible for the overall management of scientific satellite missions in China,is China’s gateway to space science.NSSC is the cradle of China’s first artificial satellite“Dongfanghong-1”(DFH-1).In the course of more than 60 years’development,NSSC has led the implementation of“Double Star Program”,the first science-driven space mission in China,and successively implemented a fleet of scientific missions under the Strategic Priority Program on Space Science(Phase I and II),such as the Dark Matter Particle Explorer(DAMPE,or Wukong),the Quantum Experiments at Space Scale(QUESS,or Micius),the Hard X-ray Modulation Telescope(HXMT,or Insight),the Taiji-1,the Advanced space-based Solar Observatory(ASO-S,or Kuafu)and the Einstein Probe(EP).Currently,the space science satellite series has been established,yielding substantial scientific output.For the future,the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE),a China-ESA joint mission,will be launched in 2025.In addition,the newly released National Mid-and Long-term Program for Space Science Development in China(2024-2050),the first of its kind at the national level,has identified five key scientific themes.A fleet of future scientific missions revolving these themes will deepen mankind’s scientific understanding of the universe.展开更多
The article briefly reviews the development history of space science in China,from the preparation period in the 1950s and 1960s,the first science mission Double Star Program(DSP),to the current Strategic Priority Pro...The article briefly reviews the development history of space science in China,from the preparation period in the 1950s and 1960s,the first science mission Double Star Program(DSP),to the current Strategic Priority Program(SPP)on space science of the Chinese Academy of Sciences(CAS).Both science objectives and payload technologies of the missions are addressed.The key management issues,such as longterm planning and the maximization of science output,are also mentioned.In addition,it also stresses the importance of international cooperation in space science.展开更多
The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importa...The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importance in China’s space exploration endeavors.Among these,MSS-1A is the world’s first high-precision scientific satellite dedicated to exploring the geomagnetic field and space environment at low latitudes.Equipped with two high-precision vector magnetometers and one scalar magnetometer,which are integrally installed on a highly stable nonmagnetic optical bench,the MSS-1A enables simultaneous high-precision measurements of both the Earth’s vector magnetic field and its scalar components.Its design integrates several state-of-the-art technologies,including arc-second-level thermal stability control,nonmagnetic thermal control for the optical bench,and ultra-high magnetic cleanliness control.These innovations effectively minimize magnetic interference originating from the satellite itself,thereby substantially improving the precision of geomagnetic field measurements and establishing a robust technical foundation for future magnetic survey satellite constellations.展开更多
The energetic particle detector on China's space station can determine the energy, flux, and direction of medium-and highenergy protons, electrons, heavy ions, and neutrons within the path of the station's orb...The energetic particle detector on China's space station can determine the energy, flux, and direction of medium-and highenergy protons, electrons, heavy ions, and neutrons within the path of the station's orbit. It also assesses the linear energy transfer(LET)spectra and radiation dose rates generated by these particles. Neutron detection is a significant component of this work, utilizing a new type of Cs_(2)LiYCl_(6): Ce scintillator material along with plastic scintillators as sensors. In-orbit testing has demonstrated the efficient identification of space neutrons and gamma rays(n/γ). This data plays a crucial role in supporting manned space engineering, scientific research, and other related fields.展开更多
Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in t...Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in the range of 30–50 km above the Yinchuan observation site,retrieved from diurnal continuous Rayleigh scattering signal observation data collected by a 589 nm lidar throughout a single day.We also present observational studies of atmospheric tides and gravity wave cases.The diurnal temperature background field and perturbation field were obtained from the lidar data using the linear fitting method;these results exhibit good consistency with the temperature perturbation field extracted from ERA5.An obvious quasi-monochromatic inertial gravity wave was detected by application of a two-dimensional Fourier transform to the nighttime observation data with complete height coverage,which revealed these characteristic gravity wave parameters:a vertical wavelength of 8.53 km,a period of 8.46 h,and a downward-propagating vertical phase velocity.A nonlinear least-squares harmonic fitting method was used to extract amplitudes and phases of atmospheric diurnal and semi-diurnal tides in the 30−34 km range,where the diurnal data were relatively complete.The amplitudes increased with height,ranging from 0.6 to 2.5 K(diurnal tide)and 0.3 to 1.9 K(semi-diurnal tide),respectively.The phases showed a decreasing trend with height,indicating that the vertical phase velocity of the tides propagates downward while the energy propagates upward.These results indicate that diurnal 589 nm lidar observations data can provide important reference values for understanding the temperature structure of the stratosphere and the dynamical characteristics of atmospheric gravity waves and tides.展开更多
Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dand...Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station.展开更多
Impact craters are important for understanding the evolution of lunar geologic and surface erosion rates,among other functions.However,the morphological characteristics of these micro impact craters are not obvious an...Impact craters are important for understanding the evolution of lunar geologic and surface erosion rates,among other functions.However,the morphological characteristics of these micro impact craters are not obvious and they are numerous,resulting in low detection accuracy by deep learning models.Therefore,we proposed a new multi-scale fusion crater detection algorithm(MSF-CDA)based on the YOLO11 to improve the accuracy of lunar impact crater detection,especially for small craters with a diameter of<1 km.Using the images taken by the LROC(Lunar Reconnaissance Orbiter Camera)at the Chang’e-4(CE-4)landing area,we constructed three separate datasets for craters with diameters of 0-70 m,70-140 m,and>140 m.We then trained three submodels separately with these three datasets.Additionally,we designed a slicing-amplifying-slicing strategy to enhance the ability to extract features from small craters.To handle redundant predictions,we proposed a new Non-Maximum Suppression with Area Filtering method to fuse the results in overlapping targets within the multi-scale submodels.Finally,our new MSF-CDA method achieved high detection performance,with the Precision,Recall,and F1 score having values of 0.991,0.987,and 0.989,respectively,perfectly addressing the problems induced by the lesser features and sample imbalance of small craters.Our MSF-CDA can provide strong data support for more in-depth study of the geological evolution of the lunar surface and finer geological age estimations.This strategy can also be used to detect other small objects with lesser features and sample imbalance problems.We detected approximately 500,000 impact craters in an area of approximately 214 km2 around the CE-4 landing area.By statistically analyzing the new data,we updated the distribution function of the number and diameter of impact craters.Finally,we identified the most suitable lighting conditions for detecting impact crater targets by analyzing the effect of different lighting conditions on the detection accuracy.展开更多
In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense...In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense large-scale traveling atmospheric disturbances(TADs)originating at high latitudes and propagating equatorward.Observations by TM02 captured the evolution of a TAD structure:An initial amplitude of~3.89×10^(-12)kg/m^(3)at hundred-kilometer scale subsequently intensified to 4.78×10^(-12)kg/m^(3),with the spatial extent expanding to the thousand-kilometer level.Significant hemispheric asymmetry was observed:the absolute density was higher predominantly in the northern hemisphere(TM02,TM06,TM07,TM11),whereas the difference in the relative density consistently showed greater enhancements in the southern hemisphere across all satellites,with the maximum north-south density differences exceeding 195%-640%above 60°latitude.In conjunction with SuperDARN(Super Dual Auroral Radar Network)observations,this striking hemispheric asymmetry can likely be attributed to disparities in plasma convection patterns between the two hemispheres.Furthermore,density perturbation characteristics exhibited strong local time(LT)dependence:Near noon(~10.7 LT,TM02 descending),the northern hemisphere onset preceded the southern onset.Conversely,near dusk(~17.6 LT,TM15 descending),the southern onset led the northern onset by approximately 3 hours.Ascending orbits(TM02,TM06,TM07,TM15)typically yielded larger global density enhancements compared with smaller southern-confined enhancements during descending orbits.Satellite TM11 showed comparable perturbations in both ascending and descending orbits.By leveraging its unique orbital architecture,the TianMu-1 constellation enables global near-simultaneous multi-LT sampling,providing a robust data foundation for both scientific research and engineering applications.展开更多
Storm-enhanced density(SED)and the tongue of ionization(TOI)are key ionospheric storm-time structures whose rapid evolution and fine-scale variability remain challenging to capture with conventional empirical high-lat...Storm-enhanced density(SED)and the tongue of ionization(TOI)are key ionospheric storm-time structures whose rapid evolution and fine-scale variability remain challenging to capture with conventional empirical high-latitude drivers.In this study,we examine the May 10–11,2024,superstorm using the Thermosphere–Ionosphere–Electrodynamics General Circulation Model(TIEGCM)with observation-constrained high-latitude forcing.Auroral precipitation parameters(energy flux and mean energy)are assimilated from a Defense Meteorological Satellite Program(DMSP)Special Sensor Ultraviolet Spectrographic Imager(SSUSI)using a multi-resolution Gaussian process(Lattice Kriging)approach,whereas high-latitude convection potentials are derived by assimilating Super Dual Auroral Radar Network(SuperDARN)observations with the Thomas and Shepherd(2018)model(TS18).For comparison,an additional simulation is performed using empirical models for both convection and auroral forcing.The results show that during the main phase of the May 10 storm,the data-driven simulation provides a more realistic depiction of the SED source region than does the empirical model run by capturing its rapid intensification more clearly and reproducing its spatial location and structural features with higher fidelity.These improvements lead to a more accurate representation of its poleward extension into the polar cap that develops into the TOI.Above the ionospheric F2 peak over the SED source region,SuperDARN-constrained potentials generate stronger and more localized E×B drifts that dominate plasma uplift and drive its transport into the polar cap,although neutral winds and downward ambipolar diffusion partially offset these effects.Below the F2 peak,neutral winds and photochemical processes play a major role in shaping the spatial extent and intensity of the SED and TOI.These results highlight the role of observation-constrained high-latitude drivers in representing ionosphere–thermosphere responses during extreme storms and suggest their relevance for improving physical interpretation and model performance.展开更多
The Triple Ionosphere Photometer(TRIPM)is a scientific payload aboard the Fengyun-3E(FY-3E)satellite,which operates in a dawn−dusk orbit.It is primarily designed for nadir observations of airglow emissions at OI 135.6...The Triple Ionosphere Photometer(TRIPM)is a scientific payload aboard the Fengyun-3E(FY-3E)satellite,which operates in a dawn−dusk orbit.It is primarily designed for nadir observations of airglow emissions at OI 135.6 nm and N_(2)Lyman-Birge-Hopfield(LBH)bands.Due to the satellite’s dawn−dusk orbital characteristics,most of TRIPM’s field of view remains in a semi-illuminated condition.Therefore,compared with airglow data of the same bands acquired under purely daytime or nighttime conditions,applying TRIPM data poses greater challenges.This study presents the first attempt to use TRIPM data for retrieving solar extreme ultraviolet(EUV)flux.Our results demonstrate that by utilizing TRIPM data in regions where photoelectron excitation dominates as the primary radiation source,the solar EUV flux(denoted as Q_(EUV))can be retrieved.Comparisons with data from the SOHO/SEM instrument reveal excellent consistency,with a seasonal correlation coefficient(R)of at least 0.95.This work thus offers a new avenue for solar EUV flux acquisition and expands the application range of TRIPM data.展开更多
A large-scale view of the magnetospheric cusp is expected to be obtained by the Soft X-ray Imager(SXI)onboard the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE).However,it is challenging to trace the three-d...A large-scale view of the magnetospheric cusp is expected to be obtained by the Soft X-ray Imager(SXI)onboard the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE).However,it is challenging to trace the three-dimensional cusp boundary from a two-dimensional X-ray image because the detected X-ray signals will be integrated along the line of sight.In this work,a global magnetohydrodynamic code was used to simulate the X-ray images and photon count images,assuming an interplanetary magnetic field with a pure Bz component.The assumption of an elliptic cusp boundary at a given altitude was used to trace the equatorward and poleward boundaries of the cusp from a simulated X-ray image.The average discrepancy was less than 0.1 RE.To reduce the influence of instrument effects and cosmic X-ray backgrounds,image denoising was considered before applying the method above to SXI photon count images.The cusp boundaries were reasonably reconstructed from the noisy X-ray image.展开更多
Detecting geomagnetic anomalies preceding earthquakes is a challenging yet promising area of research that has gained increasing attention in recent years.This study introduces a novel reconstruction-based modeling ap...Detecting geomagnetic anomalies preceding earthquakes is a challenging yet promising area of research that has gained increasing attention in recent years.This study introduces a novel reconstruction-based modeling approach enhanced by negative learning,employing a Bidirectional Long Short-Term Memory(BiLSTM)network explicitly trained to accurately reconstruct non-seismic geomagnetic signals while intentionally amplifying reconstruction errors for seismic signals.By penalizing the model for accurately reconstructing seismic anomalies,the negative learning approach effectively magnifies the differences between normal and anomalous data.This strategic differentiation enhances the sensitivity of the BiLSTM network,enabling improved detection of subtle geomagnetic anomalies that may serve as earthquake precursors.Experimental validation clearly demonstrated statistically significant higher reconstruction errors for seismic signals compared to non-seismic signals,confirmed through the Mann-Whitney U test with a p-value of 0.0035 for Root Mean Square Error(RMSE).These results provide compelling evidence of the enhanced anomaly detection capability achieved through negative learning.Unlike traditional classification-based methods,negative learning explicitly encourages sensitivity to subtle precursor signals embedded within complex geomagnetic data,establishing a robust basis for further development of reliable earthquake prediction methods.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFC2200100)the CAS's Strategic Pioneer Program on Space Science(Grant No.XDA1502110201)。
文摘Tilt-to-length(TTL)coupling noise is a critical issue in space-based gravitational wave detection due to its complex dependence on multiple interacting factors,which complicates the identification of dominant parameters.To address this challenge,we develop a simulation model of the Taiji scientific interferometer,generating noise datasets under multiparameter conditions.Given the uniqueness of the telescope as well as the convergence behavior of the algorithm,the analysis is structured hierarchically:(i)the telescope level and(ii)the optical bench level.A hierarchical framework combining XGBoost and SHapley Additive exPlanations(SHAP)values is employed to model the intricate relationships between parameters and TTL coupling noise,supplemented by sensitivity analysis.Our results identify pointing jitter and telescope radius as the dominant parameters at the telescope level,while the angles of the plane mirrors and beam splitters are most influential at the optical bench level.The parameter space is reduced from 86 dimensions to 14 dimensions without sacrificing model accuracy.This approach offers actionable insights for optimizing the Taiji interferometer design.
文摘The most important all-round progress in China's Space Science in recent years is the official go-ahead of Strategic Priority Program(SPP) on Space Science in 2011,which marks China's space science has entered a new stage.SPP on Space Science includes 4 satellites(DAMPE,SJ-10,QUESS and HXMT),the Intensive Study of Future Space Science Missions,and the Advanced Research of Space Science Missions and Payloads.It is expected that the innovative breakthroughs will be achieved,and the great leaps of related high-technology will be driven through both independent space science missions and international cooperation.The implementation of the SPP on Space Science will enable the rapid development of China's space science endeavor,and contribute to the progress of human civilization.
文摘The Strategic Priority Program on Space Science in 2011–2017(hereafter referred to as SPP Ⅰ),which officially went ahead in 2011, marks that a new chapter of Chinese space endeavor has been opened.The 4 satellites, Wukong/DAMPE, SJ-10, Mozi/QUESS and Insight/HXMT, has been achieving promising scientific results since their launch, e.g., Wukong directly detected a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons. To enable the sustainable development of China's space science endeavor,the Strategic Priority Program Ⅱ on Space Science(hereafter referred to as SPP Ⅱ) was officially approved in late 2017. SPP Ⅱ includes 4 satellites—EP, ASO-S, SMILE and GECAM, Intensive Study of Future Space Science Missions, Advanced Research of Space Science Missions and Payloads, Space Science Mission Concept Research, and Data Analysis Research. Dedicated to exploring the unknown, the program is aiming to address scientific questions such as the origin and evolution of the universe and life, search for extraterrestrial life,and the impact of the Sun and the solar system on Earth and human development. Chinese space science community is committed to contributing to the progress of human civilization.
基金Supported by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA15060102)。
文摘The Strategic Priority Program(SPP)on Space Science,which is under the leadership of the Chinese Academy of Sciences(CAS),has established China’s space science satellite series from scratch.A number of major scientific achievements have been made by the first phase of the Program(SPPⅠ),while SPPⅡhas been currently being implemented.The future development of space science needs urgent top-level planning and advanced layout to clarify the overall goal and investment portfolio from 2025 to 2030.We will briefly introduce the initiative and possible space science missions of SPPⅢ,including the preparatory work which already started in July 2021.Following the effective administrative tradition since SPPⅠ,National Space Science Center(NSSC,CAS)is responsible for the whole procedure,including soliciting,assessment,and implementation of SPPⅢ.Brief information on the 13 candidate missions will be described,including missions in the fields of astronomy&astrophysics,exoplanets,heliophysics and planetary&Earth science,respectively.
基金Supported by Consultation and Evaluation Program on Academic Divisions of the Chinese Academy of Sciences(2022-DX02-B-007)。
文摘Since 2011,the Chinese Academy of Sciences(CAS)has implemented the Strategic Priority Program on Space Science(SPP).A series of scientific satellites have been developed and launched,such as Dark Matter Particle Explorer(DAMPE),Quantum Experiments at Space Scale(QUESS),Advanced Space-based Solar Observatory(ASO-S),Einstein Probe(EP),and significant scientific outcomes have been achieved.In order to plan the future space science missions in China,CAS has organized the Chinese space science community to conduct medium and long-term development strategy studies,and summarized the major scientific frontiers of space science as“One Black,Two Dark,Three Origins and Five Characterizations”.Five main scientific themes have been identified for China’s future breakthroughs,including the Extreme Universe,Space-Time Ripples,the Panoramic View of the Sun and Earth,the Habitable Planets,and Biological&Physical Science in Space.Space science satellite missions to be implemented before 2030 are proposed accordingly.
基金Supported by the Strategic Priority Program on Space Science of the Chinese Academy of Sciences(XDA15000000)。
文摘In May 2018,the second phase of the Strategic Priority Program on Space Science(SPP II)was officially approved by the Chinese Academy of Sciences,in view of the significant scientific achievements of the first phase of the Strategic Priority Program on Space Science(SPP I)which includes 4 space science missions:the Dark Matter Particle Explorer(DAMPE),ShiJian-10(SJ-10),Quantum Experiments at Space Scale(QUESS)and Hard X-ray Modulation Telescope(HXMT).Aiming to address fundamental scientific questions,SPP II focuses on two major themes:How the universe and life originate and evolve and What is the relationship between the solar system and human beings.In areas that Chinese scientists have advantages,new space science missions including Graviational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),the Advanced space-based Solar Observatory(ASO-S),the Einstein Probe(EP),and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)have been approved in the framework of SPP II.This paper presents the research highlights of the SPP I,introduces the recent progress of SPP II,and puts forward the prospects for future development.
文摘Strategic Priority Research Program on Space Science has gained remarkable achievements. Space Environment Prediction Center(SEPC) affiliated with the National Space Science Center(NSSC) has been providing space weather services and helps secure space missions. Presently, SEPC is capable to offer a variety of space weather services covering many phases of space science missions including planning, design, launch,and orbital operation. The service packages consist of space weather forecasts, warnings, and effect analysis that can be utilized to avoid potential space weather hazard or reduce the damage caused by space storms,space radiation exposure for example. Extensive solar storms that occurred over Chinese Ghost Festival(CGF)in September 2017 led to a large enhancement of the solar energetic particle flux at 1 AU, which affected the near Earth radiation environment and brought great threat to orbiting satellites. Based on the space weather service by SEPC, satellite ground support groups collaborating with the space Tracking, Telemetering and Command system(TT&C) team were able to take immediate measures to react to the CGF solar storm event.
基金supported by the Special Funding Project for Space Debris and Near-Earth Asteroids Defense Research, China (No. KJSP2023020303)Beijing Municipal Science and Technology Commission, China (No. Z181100002918004)the Youth Innovation Promotion Association, Chinese Academy of Sciences (No. 2022146)
文摘Implementing the flyby to Near-Earth Asteroids (NEAs) with the potential impact risks to the Earth allows for obtaining detailed physical parameters, thereby supporting the high-precision orbit prediction and planetary defense strategy. Different from those conducted asteroid flyby missions, in the 12th China Trajectory Optimization Competition (CTOC-12), a NEAs flyby trajectory design problem using reusable probes that depart from a Lunar Distant Retrograde Orbit (DRO) station in the cislunar space was released. The objective was flyby to as many NEAs as possible using up to 20 probes within a total of 10 years. The ∑ team proposed a solution that can explore 47 NEAs using 11 probes, ranking the first in the competition. In this paper, the methods and results from the winning team are introduced, including mission analysis and preliminary design, and low-energy transfer trajectory optimization. In particular, a round-trip trajectory is divided into three phases: deep space transfer, indirect transfer between the Earth to DRO, and DRO phasing and rendezvous. With the combination of global optimization and local optimization algorithms, the required velocity increments to change the orbital planes are effectively reduced, thus increasing the number of the explored NEAs. The final solution of our team is presented and the results are compared with those of the top three teams. The competition demonstrates that the regularization of flyby missions from the cislunar space to explore NEAs with the potential impact risks to the Earth is the feasible and promising.
文摘The National Space Science Center of the Chinese Academy of Sciences(NSSC,CAS),as the leading institute responsible for the overall management of scientific satellite missions in China,is China’s gateway to space science.NSSC is the cradle of China’s first artificial satellite“Dongfanghong-1”(DFH-1).In the course of more than 60 years’development,NSSC has led the implementation of“Double Star Program”,the first science-driven space mission in China,and successively implemented a fleet of scientific missions under the Strategic Priority Program on Space Science(Phase I and II),such as the Dark Matter Particle Explorer(DAMPE,or Wukong),the Quantum Experiments at Space Scale(QUESS,or Micius),the Hard X-ray Modulation Telescope(HXMT,or Insight),the Taiji-1,the Advanced space-based Solar Observatory(ASO-S,or Kuafu)and the Einstein Probe(EP).Currently,the space science satellite series has been established,yielding substantial scientific output.For the future,the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE),a China-ESA joint mission,will be launched in 2025.In addition,the newly released National Mid-and Long-term Program for Space Science Development in China(2024-2050),the first of its kind at the national level,has identified five key scientific themes.A fleet of future scientific missions revolving these themes will deepen mankind’s scientific understanding of the universe.
文摘The article briefly reviews the development history of space science in China,from the preparation period in the 1950s and 1960s,the first science mission Double Star Program(DSP),to the current Strategic Priority Program(SPP)on space science of the Chinese Academy of Sciences(CAS).Both science objectives and payload technologies of the missions are addressed.The key management issues,such as longterm planning and the maximization of science output,are also mentioned.In addition,it also stresses the importance of international cooperation in space science.
文摘The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importance in China’s space exploration endeavors.Among these,MSS-1A is the world’s first high-precision scientific satellite dedicated to exploring the geomagnetic field and space environment at low latitudes.Equipped with two high-precision vector magnetometers and one scalar magnetometer,which are integrally installed on a highly stable nonmagnetic optical bench,the MSS-1A enables simultaneous high-precision measurements of both the Earth’s vector magnetic field and its scalar components.Its design integrates several state-of-the-art technologies,including arc-second-level thermal stability control,nonmagnetic thermal control for the optical bench,and ultra-high magnetic cleanliness control.These innovations effectively minimize magnetic interference originating from the satellite itself,thereby substantially improving the precision of geomagnetic field measurements and establishing a robust technical foundation for future magnetic survey satellite constellations.
基金This mission was supported by the China Manned Space Office。
文摘The energetic particle detector on China's space station can determine the energy, flux, and direction of medium-and highenergy protons, electrons, heavy ions, and neutrons within the path of the station's orbit. It also assesses the linear energy transfer(LET)spectra and radiation dose rates generated by these particles. Neutron detection is a significant component of this work, utilizing a new type of Cs_(2)LiYCl_(6): Ce scintillator material along with plastic scintillators as sensors. In-orbit testing has demonstrated the efficient identification of space neutrons and gamma rays(n/γ). This data plays a crucial role in supporting manned space engineering, scientific research, and other related fields.
基金supported by the Key Research Program of the Chinese Academy of Sciences(Grant NO.KGFZD-145-23-17)the Specialized Research Fund for State Key Laboratories.
文摘Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in the range of 30–50 km above the Yinchuan observation site,retrieved from diurnal continuous Rayleigh scattering signal observation data collected by a 589 nm lidar throughout a single day.We also present observational studies of atmospheric tides and gravity wave cases.The diurnal temperature background field and perturbation field were obtained from the lidar data using the linear fitting method;these results exhibit good consistency with the temperature perturbation field extracted from ERA5.An obvious quasi-monochromatic inertial gravity wave was detected by application of a two-dimensional Fourier transform to the nighttime observation data with complete height coverage,which revealed these characteristic gravity wave parameters:a vertical wavelength of 8.53 km,a period of 8.46 h,and a downward-propagating vertical phase velocity.A nonlinear least-squares harmonic fitting method was used to extract amplitudes and phases of atmospheric diurnal and semi-diurnal tides in the 30−34 km range,where the diurnal data were relatively complete.The amplitudes increased with height,ranging from 0.6 to 2.5 K(diurnal tide)and 0.3 to 1.9 K(semi-diurnal tide),respectively.The phases showed a decreasing trend with height,indicating that the vertical phase velocity of the tides propagates downward while the energy propagates upward.These results indicate that diurnal 589 nm lidar observations data can provide important reference values for understanding the temperature structure of the stratosphere and the dynamical characteristics of atmospheric gravity waves and tides.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0711402)the Specialized Research Fund for State Key Laboratories。
文摘Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station.
基金the National Key Research and Development Program of China (Grant No.2022YFF0711400)the National Space Science Data Center Youth Open Project (Grant No. NSSDC2302001)
文摘Impact craters are important for understanding the evolution of lunar geologic and surface erosion rates,among other functions.However,the morphological characteristics of these micro impact craters are not obvious and they are numerous,resulting in low detection accuracy by deep learning models.Therefore,we proposed a new multi-scale fusion crater detection algorithm(MSF-CDA)based on the YOLO11 to improve the accuracy of lunar impact crater detection,especially for small craters with a diameter of<1 km.Using the images taken by the LROC(Lunar Reconnaissance Orbiter Camera)at the Chang’e-4(CE-4)landing area,we constructed three separate datasets for craters with diameters of 0-70 m,70-140 m,and>140 m.We then trained three submodels separately with these three datasets.Additionally,we designed a slicing-amplifying-slicing strategy to enhance the ability to extract features from small craters.To handle redundant predictions,we proposed a new Non-Maximum Suppression with Area Filtering method to fuse the results in overlapping targets within the multi-scale submodels.Finally,our new MSF-CDA method achieved high detection performance,with the Precision,Recall,and F1 score having values of 0.991,0.987,and 0.989,respectively,perfectly addressing the problems induced by the lesser features and sample imbalance of small craters.Our MSF-CDA can provide strong data support for more in-depth study of the geological evolution of the lunar surface and finer geological age estimations.This strategy can also be used to detect other small objects with lesser features and sample imbalance problems.We detected approximately 500,000 impact craters in an area of approximately 214 km2 around the CE-4 landing area.By statistically analyzing the new data,we updated the distribution function of the number and diameter of impact craters.Finally,we identified the most suitable lighting conditions for detecting impact crater targets by analyzing the effect of different lighting conditions on the detection accuracy.
基金the National Space Science Center (NSSC) of the Chinese Academy of Sciences for full support of this research workfunded by the Tian Mu-1 Constellation Atmospheric Density Detector (Grant No. E3C1162110)
文摘In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense large-scale traveling atmospheric disturbances(TADs)originating at high latitudes and propagating equatorward.Observations by TM02 captured the evolution of a TAD structure:An initial amplitude of~3.89×10^(-12)kg/m^(3)at hundred-kilometer scale subsequently intensified to 4.78×10^(-12)kg/m^(3),with the spatial extent expanding to the thousand-kilometer level.Significant hemispheric asymmetry was observed:the absolute density was higher predominantly in the northern hemisphere(TM02,TM06,TM07,TM11),whereas the difference in the relative density consistently showed greater enhancements in the southern hemisphere across all satellites,with the maximum north-south density differences exceeding 195%-640%above 60°latitude.In conjunction with SuperDARN(Super Dual Auroral Radar Network)observations,this striking hemispheric asymmetry can likely be attributed to disparities in plasma convection patterns between the two hemispheres.Furthermore,density perturbation characteristics exhibited strong local time(LT)dependence:Near noon(~10.7 LT,TM02 descending),the northern hemisphere onset preceded the southern onset.Conversely,near dusk(~17.6 LT,TM15 descending),the southern onset led the northern onset by approximately 3 hours.Ascending orbits(TM02,TM06,TM07,TM15)typically yielded larger global density enhancements compared with smaller southern-confined enhancements during descending orbits.Satellite TM11 showed comparable perturbations in both ascending and descending orbits.By leveraging its unique orbital architecture,the TianMu-1 constellation enables global near-simultaneous multi-LT sampling,providing a robust data foundation for both scientific research and engineering applications.
基金The Shandong Provincial Natural Science Foundation(Grant No.ZR2022JQ18)supported this worksupported by the National Natural Science Foundation of China(NNFSC)Youth Program(Grant No.42304168)+1 种基金supported by the National Key R&D Program of China(Grant No.2022YFF0504400)the NNSFC(Grant Nos.42188101 and 42174210)。
文摘Storm-enhanced density(SED)and the tongue of ionization(TOI)are key ionospheric storm-time structures whose rapid evolution and fine-scale variability remain challenging to capture with conventional empirical high-latitude drivers.In this study,we examine the May 10–11,2024,superstorm using the Thermosphere–Ionosphere–Electrodynamics General Circulation Model(TIEGCM)with observation-constrained high-latitude forcing.Auroral precipitation parameters(energy flux and mean energy)are assimilated from a Defense Meteorological Satellite Program(DMSP)Special Sensor Ultraviolet Spectrographic Imager(SSUSI)using a multi-resolution Gaussian process(Lattice Kriging)approach,whereas high-latitude convection potentials are derived by assimilating Super Dual Auroral Radar Network(SuperDARN)observations with the Thomas and Shepherd(2018)model(TS18).For comparison,an additional simulation is performed using empirical models for both convection and auroral forcing.The results show that during the main phase of the May 10 storm,the data-driven simulation provides a more realistic depiction of the SED source region than does the empirical model run by capturing its rapid intensification more clearly and reproducing its spatial location and structural features with higher fidelity.These improvements lead to a more accurate representation of its poleward extension into the polar cap that develops into the TOI.Above the ionospheric F2 peak over the SED source region,SuperDARN-constrained potentials generate stronger and more localized E×B drifts that dominate plasma uplift and drive its transport into the polar cap,although neutral winds and downward ambipolar diffusion partially offset these effects.Below the F2 peak,neutral winds and photochemical processes play a major role in shaping the spatial extent and intensity of the SED and TOI.These results highlight the role of observation-constrained high-latitude drivers in representing ionosphere–thermosphere responses during extreme storms and suggest their relevance for improving physical interpretation and model performance.
基金supported financially by National Natural Science Foundation of China(Grant No.42174226,42474239)National Key Research and Development Program(2022YFF0503901)China Meteorological Administration‘Ionospheric Forecast and Alerting’Youth Innovation Team(CMA2024QN09).
文摘The Triple Ionosphere Photometer(TRIPM)is a scientific payload aboard the Fengyun-3E(FY-3E)satellite,which operates in a dawn−dusk orbit.It is primarily designed for nadir observations of airglow emissions at OI 135.6 nm and N_(2)Lyman-Birge-Hopfield(LBH)bands.Due to the satellite’s dawn−dusk orbital characteristics,most of TRIPM’s field of view remains in a semi-illuminated condition.Therefore,compared with airglow data of the same bands acquired under purely daytime or nighttime conditions,applying TRIPM data poses greater challenges.This study presents the first attempt to use TRIPM data for retrieving solar extreme ultraviolet(EUV)flux.Our results demonstrate that by utilizing TRIPM data in regions where photoelectron excitation dominates as the primary radiation source,the solar EUV flux(denoted as Q_(EUV))can be retrieved.Comparisons with data from the SOHO/SEM instrument reveal excellent consistency,with a seasonal correlation coefficient(R)of at least 0.95.This work thus offers a new avenue for solar EUV flux acquisition and expands the application range of TRIPM data.
基金funded by the National Natural Science Foundation of China(NNSFC)under Grant Numbers 42322408,42188101,and 42441809Additional support was provided by the Climbing Program of the National Space Science Center(NSSC,Grant No.E4PD3005)as well as the Specialized Research Fund for State Key Laboratories of China.
文摘A large-scale view of the magnetospheric cusp is expected to be obtained by the Soft X-ray Imager(SXI)onboard the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE).However,it is challenging to trace the three-dimensional cusp boundary from a two-dimensional X-ray image because the detected X-ray signals will be integrated along the line of sight.In this work,a global magnetohydrodynamic code was used to simulate the X-ray images and photon count images,assuming an interplanetary magnetic field with a pure Bz component.The assumption of an elliptic cusp boundary at a given altitude was used to trace the equatorward and poleward boundaries of the cusp from a simulated X-ray image.The average discrepancy was less than 0.1 RE.To reduce the influence of instrument effects and cosmic X-ray backgrounds,image denoising was considered before applying the method above to SXI photon count images.The cusp boundaries were reasonably reconstructed from the noisy X-ray image.
基金funded by the Ministry of Higher Education through Universiti Putra Malaysia(UPM)under Grant FRGS/1/2023/STG07/UPM/02/4.
文摘Detecting geomagnetic anomalies preceding earthquakes is a challenging yet promising area of research that has gained increasing attention in recent years.This study introduces a novel reconstruction-based modeling approach enhanced by negative learning,employing a Bidirectional Long Short-Term Memory(BiLSTM)network explicitly trained to accurately reconstruct non-seismic geomagnetic signals while intentionally amplifying reconstruction errors for seismic signals.By penalizing the model for accurately reconstructing seismic anomalies,the negative learning approach effectively magnifies the differences between normal and anomalous data.This strategic differentiation enhances the sensitivity of the BiLSTM network,enabling improved detection of subtle geomagnetic anomalies that may serve as earthquake precursors.Experimental validation clearly demonstrated statistically significant higher reconstruction errors for seismic signals compared to non-seismic signals,confirmed through the Mann-Whitney U test with a p-value of 0.0035 for Root Mean Square Error(RMSE).These results provide compelling evidence of the enhanced anomaly detection capability achieved through negative learning.Unlike traditional classification-based methods,negative learning explicitly encourages sensitivity to subtle precursor signals embedded within complex geomagnetic data,establishing a robust basis for further development of reliable earthquake prediction methods.
