China’s deep space exploration has gradually developed from technology and science-driven to the stage dominated by science, leading to technological advances. Under our demand for high-quality development in deep space exploration, the Mega Interconnected Knowledge System in Deep Space Exploration (MIKSE) was innovatively proposed with its concept and scheme conceiving. Centering around the scientific goals, deep space exploration engineering, science, technology, and big data in the application were collected, techniques including artificial intelligence and cloud computing were utilized to perform organic organization, information association, and knowledge mining on relevant elements, a large model with genealogical associations and networks of connections was built, and an intelligent big knowledge platform was established. With the help of this platform, historical data and its current capabilities can be fully utilized to support generative knowledge and information for the future planning and development of deep space exploration and promote the paradigm shift of data-driven deep space research.

Soft landing exploration is an important method for exploring extraterrestrial objects, and guidance, navigation and control (GNC) is the key to successful soft landing of extraterrestrial objects. Firstly, the development status of soft-landing missions of foreign and domestic celestial bodies such as Moon, Mars, and small celestial bodies was reviewed. On this basis, the typical GNC schemes for soft landing missions of extraterrestrial objects and the main progress of autonomous navigation and control technology were summarized. Finally, the key technologies for autonomous navigation and control that require special attention and development were proposed for future pinpoint soft-landing missions of extraterrestrial objects, in order to provide the experience and reference for future technological development.

The reflection spectra of satellites are shifted to short wavelengths when seasonal scintillation caused by solar wings occurs, and the shorter wavelength UV band has potential advantages in space target solar wing detection. The space target detection signal-to-noise ratio and detection distance models were developed for space target detection. For the most influential material properties in the model, the spectral reflectance of typical satellite materials and solar wing cell materials in the UV and visible bands were measured, and other influencing factors such as detector and deep space background in the model were also analyzed. Using the SJ-5 and Skynet 5D satellites as examples, it was verified that there was indeed a significant advantage of UV in solar wing detection. The results show that compared with the main body visible detection of the satellite, the solar wing UV detection signal-to-noise ratio is enhanced by 1.3~1.6 times, and the detection distance can be increased by 1.5~1.8 times by the combination of UV and visible light. UV has obvious technical advantages over visible light in detection scenes such as Earth’s limb, occultation and engine tail flame detection during satellite deorbiting, thus UV detection has the obvious advantages of cost-efficiency ratio and detection capability in space target detection.

A lot of dust particles are ejected from the surfaces of the Jovian irregular moons by the impact of interplanetary meteoroids. In this paper, the dynamics of dust particles originating from the irregular satellites in the complicated Jupiter system with various perturbation forces were studied, using both the analytical method and the numerical simulation method. By analyzing the conserved effective Hamiltonian quantity and phase portraits in the orbit-averaged model that describes the long-term evolution of motion of dust, it is concluded that dust particles originating from the prograde satellites tend to be distributed in the direction away from the Sun, while dust particles originating from the retrograde satellite are predominantly distributed in the direction towards the Sun. With long-term numerical simulation, it is found that the orbits of particles originating from prograde satellites are more stable than those of particles originating from retrograde satellites, and the orbital stabilities of large-size dust particles are greater than those of small-size particles.

To overcome the difficulty of absolute optical navigation in unknown environments, an intelligent fusion autonomous navigation method for Mars precise landing was proposed. Considering the difficulties of the inability to detect features and the low efficiency of recognition brought by high texture similarity in the extraterrestrial environment and perspective scaling between images, an unsupervised homography network was constructed to estimate the inter frame motion of the lander. Based on the inertial measurement information, a recursive model of the lander state was established. Using the established measurement model and state recursive model, real-time estimation of the lander position, velocity, and attitude was achieved through UKF. The simulation results verify the effectiveness of the proposed method without the need of feature detection and matching.

Only one vision sensor is incompetent for estimating the motion state of small body. In order to solve this problem, a small body motion state estimation method based on the fusion of camera and LIDAR was proposed. Firstly, a fused camera and LIDAR measurement model was built. By tracking image feature points with depth information, extended Kalman filter was used to estimate the spin angular velocity, spin axis direction, position and velocity of small body. Secondly, a feature fusion matrix was designed to achieve real-time updates of image feature points, point clouds, and fused feature points. Thirdly, the effectiveness of this algorithm and the impact of the number of feature points, observation height, and noise on the algorithm were analyzed. Simulation results show that the accuracy of the proposed algorithm is significantly higher than that of the spin parameter estimation algorithm of small bodies based on monocular camera.

The principle of radio frequency ion thrusters（RIT），as well as the research history and achievements of micro-newton and milli-Newton RIT at home and abroad in the past 60 years，was explained in detail. The radio frequency ion propulsion system involves a number of key technical challenges. Preliminary solutions to the problems of propellant selection， radio frequency（RF）circuit impedance matching，gas flow control，electrical neutralization control and lifetime were proposed， and the development trend and research direction were put forward combined with the future application of RIT.

In this paper，scientific objectives and payloads configuration of international asteroid exploration missions in the past three decades were reviewed. On the basis of summarizing the main scientific questions of asteroid exploration， the selection of detection objects，scientific objectives and payloads configuration of China’s asteroid exploration project，which named Tianwen-2 mission were discussed. Focusing on the realization of scientific objectives，corresponding scientific research contents and payload technical specifications were proposed.

Lava tubes, formed by the flow and cooling processes of volcanic lava, have been discovered on the surface of several heavenly bodies in the solar system and have become a window into the volcanic activity and thermal history of Earth-like planets. At the same time, lava tubes have extremely important scientific and engineering applications because of their thermostatic and radiation-proof interiors, which are also natural shelters for future human exploration activities or extraterrestrial survival. In this paper, the formation mechanism, detection and identification methods of lava tubes, and the distribution of lava tubes on the surface of different heavenly bodies in the solar system were summarized, the scientific significance and application prospects of lava tube detection were discussed. It was proposed that the Earth’s lava tubes are the most important objects for planetary lava tube analogical studies and detection, and the theory and methodology of the analogical studies of lava tubes were introduced, to provide theoretical basis and simulation experimental support for future exploration of extraterrestrial lava tubes.

Lava tubes are one of the prime candidates for establishing extraterrestrial bases. To verify the feasibility of using ground-penetrating radar to detect lava tubes on extraterrestrial bodies, this paper first conducted a technical study to validate the detection of lava tubes using a 400 MHz ground-penetrating radar system on the Seventy-Two Caves and Wolong Cave in the Shishan Volcanic Group in Haikou, Hainan. It is found that the upper interface of the lava tube is clearly displayed when the depth of the tube is 2 m, and the radar image shows the upper and lower boundaries when the height is less than 3 meters. Additionally, the genetic algorithm is employed to inverse the dielectric constant of the lava tube’s wall. The reliability of the genetic algorithm in calculating the dielectric constant is validated through comparison with results obtained from the depth method and sample measurement. Furthermore, the analysis of samples establishes a simple relationship between porosity and dielectric constant. These findings are of significant importance for assessing the underground spatial distribution and wall stability of the lava tubes, providing a reference for future lunar base establishment.

Based on the phenomenon of single-side local high temperature of throat and high jump of weld temperature during steady-state test ignition of the engine. which seriously endangers the reliability of the engine，CFD simulation was used to model the structure of the head injector and optimize the distribution structure in the flow channel combined with the flow resistance mathematical model. To achieve the reduction of jet flow resistance and improve the non-uniformity of flow caused by impact，and optimize the combustion structure and liquid film cooling scheme in the side zone by adjusting the impact parameters，optimize the mixing ratio in the side zone，and reduce the throat temperature and circumferential temperature difference. The improved engine has been verified by experiments. Under the condition of unchanged performance，the temperature of the high-altitude simulated thermal test throat was reduced from nearly 1 500 ℃ to 1 270 ℃，the temperature at the headbody weld was reduced from 520 ℃ to 310 ℃，and the temperature difference of the engine body was controlled within 50 ℃，which effectively solved the problem of high temperature in the engine throat. The service life and reliability of the engine were improved.

The stable celestial geological structure，the suitable distance from the Earth to the Moon，and no dense atmosphere and global magnetic field make the Moon a natural and excellent laboratory for the monitoring and research of the Sun-Earth-Moon space weather. This paper reviews the progress of lunar space weather detection and research，and surveys the key scientific problems of lunar space weather and the problems of its prediction application，proposes the concept of the Moon-based space weather monitoring station，set up the specific scientific objectives of the monitoring station，and finally introduces its three major systems and the relationships among them，including the monitoring system，the scientific research system，and the modeling and forecasting system. The establishment of a Moon-based space weather monitoring station is of great scientific significance for studying the mechanism of solar eruptions，the coupling of the Sun to the Earth and the Moon，and the local variations of the Moon’s environment. It will also promote the development of lunar space weather modeling and prediction technologies and improve the capability in providing space environmental safeguard services for future lunar explorations.

As for China’s first near-Earth asteroid defense on-orbit verification mission，the defensive disposal of the potential risk of near-Earth asteroid impact on the Earth was verified. The scientific objectives，scientific exploration mission were put forward，the scientific payload requirements analysis was conducted，scientific payload configuration was proposed. This study may provide a basis for decision-making for the implementation of the future asteroid defense missions .

To realize all the six components of terminal position and velocity control for pinpoint landing, throttleable engines are usually needed. In order to reduce economic cost and technique risk, a constant thrust guidance method with yaw maneuver for pinpoint landing was proposed in this paper. The range in the flight line was controlled by yaw maneuver which regulated the in-plane component of the thrust. And a strategy to change the sign of heading angle was performed to eliminate the position and velocity errors in the cross direction, which made the trajectory in horizon plane resemble the letter “W”. This method steered the spacecraft to a given target point with a little more fuel consumption. Simulation results show that the method proposed in this paper is easy to use and efficient.

With the development of high-precision space exploration missions such as gravitational wave detection and Earth gravity field detection，the accuracy requirements of propulsion systems are further improved，and it is urgent to develop neutralizers with stable output of small current. In this paper，the working stability and electron extraction of carbon nanotube field emission neutralizer were experimentally studied. The current fluctuation characteristics before and after aging were tested， and spearman rank correlation test was used to analyze the correlation between background electric field and current fluctuation. Besides，three kinds of gate with different aperture were used to test the extraction characteristics of the neutralizer，and the influence mechanism of gate aperture on the performance of the neutralizer was analyzed. The experimental results show that aging treatment is helpful to improve the working stability of the neutralizer，and the background electric field of the emitter has a strong correlation with the instability of the emission current. The gate aperture has influence on both emission and extraction performance，and the 1 mm gate aperture has the best performance under experimental conditions. The results can provide some guidance for neutralizer configuration and structure design in propulsion system.

Mapped Chebyshev pseudospectral convex optimization approach was proposed for Martian ascent trajectory optimization. Firstly, the lossless convexification technique was used to convexify the fuel-optimal problem of Martian ascent. Then, the convexified problem was discretized at mapped Chebyshev-Gauss-Lobatto points and interpolated by the barycentric rational interpolation techniques. Finally, the sequential convex optimization method was used to solve the convex problem iteratively to obtain the numerical optimal solution. Simulation results show that the proposed method is superior to the classical sequential convex optimization method in computational efficiency, and effectively improves the ill-condition of standard Chebyshev differential matrices.

To meet the demand for long-life carbon nanotube field emission cathode in deep space exploration，the failure mechanism of CNTs cathode was investigated，and a long-life CNTs cathode design was introduced. Patterning the CNTs as an array of CNTs island offers a way to eliminate the shielding effects of electrical field. In this way the areas of emitting CNTs are larger，which avoids over-heating on a small emission area. A bonding technique was introduced，the contact between CNTs and substrate was maintained by molecular forces previously，melting metal was introduced as the bonding layer. The mechanical robustness of the CNTs cathode was enhanced while the electrical/thermal resistance was reduced. Performance tests were conducted on the prototype in a high vacuum environment. The prototype produced a current of 0–1 mA with a resolution less than 2 μA and the noise level was less than 1 μA/Hz^1/2@0.01–1 Hz. The prototype was tested by over 550 hours' continuous emitting，showing good stability in long-term use.

TheThe process of an asteroid impacting the land is a complex non-linear dynamic process，which is difficult to study by using model tests. Numerical simulation provides an important tool for the analysis of this process. In this study，the large-scale numerical simulation of the dynamic process of the asteroid impacting land was realized initially by using the self-developed software CoSim-DEM based on the discrete element method (DEM). Based on the numerical simulation results，the four stages of the impact process—initial contact，impact excavation, high-speed ejection and adjustment—were simulated；the incidence angle and the dynamic behaviors of the asteroid during the impact process would affect the topographic characteristics of the crater. This study also indicates that large-scale numerical methods can be used to perform the analysis of dynamic process of the asteroid impacting the earth, and provide support for asteroid defense.

The multi-constrained trajectory of minimal fuel consumption was achieved in this paper for the lunar hover hop without lateral thrusters. The hover hop was divided to 3 phases: the vertical rise, the horizontal traverse and the vertical descent. The optimal control of the vertical rise and the vertical descent was bang-bang function. For the first time the control variable of the horizontal traverse was converted from thrust to angle rate, with position, velocity and angle rate considered. The preliminary form of the optimal angle rate for the horizontal traverse was developed by application of the Pontryagin’s minimum principle. With further study on the continuity of the singular point and the number of switching times of the control variable, it was confirmed that the optimal angle rate program consisted of either the maximum or the minimum and there were 2 switchings. A numerical approach to searching the switching points was presented. Simulation results show that the approach with high accuracy and low complexity can potentially be implemented onboard for trajectory optimization.

During the attachment process of small body spacecraft, there are scale, viewpoint and illumination variations in the image, making it difficult for traditional feature-matching algorithms to obtain accurate matches. In this paper, a small-body cross-scale illumination invariant matching algorithm is proposed. To address the problem of scale changes in the image during the attachment process, the global attention mechanism is combined with the dilated convolution to construct a scale adaptive adjustment module; the viewpoint invariant feature extraction module is designed to solve the problem of low matching accuracy under the large viewpoint changes in the feature matching algorithm; the self-attention mechanism is combined with the inter-attention mechanism to establish the feature dependency relationship, and the illumination invariant features are extracted. Experimental validation is carried out using the real images of Ceres and Bennu, and the results show that the proposed algorithm achieves an accuracy of more than 89% under large scale, view angle and illumination changes.

To address such the problems as the limitation of the invisible zone of the ground-based monitoring system for near-Earth asteroids and the insufficient discovery and cataloguing capabilities of the monitoring system，a solution of a space-based distant retrograde orbit 4-satellite monitoring system was proposed.Then，the space-based monitoring system's to solve the problems mentioned above was quantified and analyzed，and a cosrreponding model for evaluating the efficiency of the system was set up. A process for the implementation of the corresponding evaluation software was given and an integration of the scoring of various elements was completed in accordance with the visible and infrared spectrum. By analyzing and evaluating，the efficiency of the distant retrograde orbit monitoring layout in compensating for the full-time visibility of the invisible zone of the ground-based monitoring system was verified，as well as the enhancement of the capability of target discovery and cataloguing. This research could provide design reference for subsequent construction of space-based monitoring system.

Based on the existing tracking and measuring conditions of China’s deep space exploration missions, the orbit determination accuracy of the DRO probe was simulated and analyzed. For the Cislunar space DRO exploration, the simulation adopted batch processing orbit determination method, selected celestial bodies centered on the Earth for orbit integration, and increased non-spherical gravitational perturbation of the moon. Under the current measurement conditions, the position and velocity accuracy of 2-day short-arc orbit determination using only range tracking data were the order of km and better than 3 cm/s respectively; for 7-day predictions, the maximum differences in the position and velocity are the order of ten kilometers and 6 cm/s respectively. When using ranging data combined with VLBI data, the position and velocity accuracy were the order of hundreds of meters and less than 0.4 cm/s respectively; for 7-day predictions, the maximum differences in the position and velocity were the order of kilometers and 2 cm/s respectively, which shows that VLBI data significantly improved the accuracy of short-arc orbit determination and prediction. Moreover, the position and velocity accuracy were better than 1 km and 1cm/s respectively when using 5-day long-arc range tracking data. For 7-day predictions, the maximum differences in the position and velocity were less than 2 km and 1cm/s respectively. This shows that an increase of ranging data significantly contributes to the accuracy of orbit determination and prediction for DRO.

For the detection of lava tubes on extraterrestrial bodies, this paper utilizes LiDAR technology to conduct field surveys on lava tubes in the Shishan Volcanic Cluster area of Haikou City, which has a high degree of similarity with the Moon and Mars. It also proposes a skylight detection method based on grid division and applies a crack detection method based on data enhancement and multi-scale feature learning network to detect the internal structure of the lava tube and study its morphology. The interior of the lave tubes is scanned in all directions using a portable handheld laser scanner in the first. Based on the high-precision point cloud data obtained by measurement, this paper completes a three-dimensional model using the ContextCapture software, and some special miniature geomorphic like skylight in the tube and the tubes’ inner fissure is detected and extracted automatically. The experimental results show that the laser scanner combined with point cloud processing software and program can efficiently, intuitively and truly restore the morphology and structure of the lava tube, conduct quantitative analysis, and detect the special miniature geomorphology in the tube.

A hazard avoidance strategy based on augmented curvature guidance was presented for complex planetary surface landing. Based on the basic curvature guidance law, a hazard avoidance augmentation term was introduced. The idea of spacecraft landing space division was used and an anti-collision zone was defined in the collision prone zone near the hazards. The continuous analytical hazard avoidance guidance law was derived based on anti-collision zone. While meeting the geometric convex trajectory state constraints, the hazard avoidance guidance law evaluated the relative position relationship between spacecraft and hazards, which can quickly steer the spacecraft away from hazards and increase landing safety. Simulation results reveal that the validity of avoiding terrain hazards on the complex planet surface and achieving pinpoint soft landing is enhanced, with good flexibility and reliability.

Given the complex and numerous morphological features during asteroid landing，which lead to challenges such as huge number of feature combinations，high computational load in online feature selection and low computational efficiency，in this paper an online multi-type feature rapid selection method was proposed. Using rapid selection criteria for multi-type features combined with search region，a method for selecting single-frame image features was established. Additionally，considering the short sampling interval，high inter-frame image overlap，and high feature inheritance probability during asteroid landing，a method for inter-frame image feature inheritance selection was proposed. Simulation experiments show that the design of single-frame image search regions and inter-frame image feature inheritance methods substantially reduces the number of feature combinations，thereby greatly enhancing the efficiency of computational and online feature selection.

This article proposed a 3D real scene modeling method for lava tubes that integrates airborne LiDAR, close-range photogrammetry, and point cloud data from GeoSLAM handheld laser scanner, with a focus on future lunar surface scientific explorations. Firstly, the entities were divided, and then entity feature extraction was performed based on semantic information. A new mesh model construction method was proposed, which uses multi-level model construction method and skeleton-plus-detail modeling method to construct the mesh model of the inner surface of the lava tube. Finally, entities were constructed separately between different layers inside the model to simulate the original state of different layers, and to measure layer thickness and volume of spallation. The 3D modeling of the lava tube located in Jingpo Lake, Heilongjiang province, shows that the 3D modeling method for lava tubes based on multi-source data fusion has high precision and high realism, providing an important reference for subsequent lunar lava tube skylight detection, Earth-Moon simulation comparison and internal exploration.

This paper, founded on the synthesis of recent exploration achievements and prior research, supplemented by on-site investigations of diverse terrestrial lava tubes, delves into the value and challenges associated with lunar lava tube exploration and development. Employing lunar remote sensing data and focusing on lunar lava tubes in areas such as Mare Fecunditatis and Mare Tranquillitatis, the paper formulates a collaborative exploration blueprint comprising lunar landing platforms, rovers, and autonomous robots. Furthermore, in line with the objective of utilizing natural cavities within lava tubes for potential lunar base construction, the paper scrutinizes the prerequisites and complications linked to lava tube modification and construction. It presents conceptual solutions, encompassing cave interior floor construction, communication and power infrastructure deployment, as well as residential facility establishment, providing a fundamental reference for the construction of future lunar bases.

Based on the Space Debris Experiment Telescope of the National Astronomical Observatories of the Chinese Academy of Sciences，together with the Yangwang-1 and Jilin-1 satellites，a space-based and ground-based collaborative monitoring experiment for near-Earth asteroids was designed and carried out. By using image processing and orbit determination methods，target detection and astronomical positioning of observation images were realized，and the orbit of near-Earth asteroids was precisely determined. Based on the analysis，the existing equipment can realize space-ground collaborative monitoring and orbit cataloging of near-Earth asteroids，and provide orbital data support for the study and estimating of impact risk of near-Earth asteroids.

An adaptive iterative guidance strategy was designed for the guidance of Mars ascent vehicle in the orbiting phase. To reduce the effects of initial state deviation and the uncertainty of the Martian environment, the remaining flight time was calculated iteratively in the guidance coordinate system in each cycle, and the optimal control angle satisfying the constraints of the target point position and velocity vector was solved under the fixed thrust of the ascender, so as to correct the flight trajectory in real time. The simulation results show that compared with the traditional open-loop guidance scheme, the proposed scheme significantly improves guidance accuracy, in which the altitude error is reduced by three orders of magnitude, the maximum velocity error is reduced to one-third of that of the original open-loop guidance, the orbital inclination and eccentricity errors at the entry point satisfy the basic engineering requirements, and it can be used as a reliable scheme for the future guidance of the Mars ascent vehicle in the orbiting phase.

In light of the demands for a micro-Newtonian level field emission electric thruster with wide，stable，precise， rapid，and persistent characteristics due to the drag-free control on satellites in space gravity wave detection missions，the mutual limitations between adjustable width range，resolution，and thrust noise should be broken through.Based on the principle of field emission thrust generation，and high-precision single pendulum to calibrate the accuracy of the model was uesd. Based on this thrust model，a flow and voltage-based active regulation strategy was established to control thrust，and a thrust feedback control strategy was proposed to maintain low thrust noise levels in a wider thrust range，accroding to the requirements for thrust control resolution and response speed. Finally，performance characterization was carried out on the developed prototype of the thruster principle，achieving 0.86-83.54 μN level，thrust resolution less than 0.1 μN，<0.1 μN/Hz^1/2，thrust noise in the millihertz frequency band less than 0.1 μN and less than 10 ms for thrust response time with constant flow.