Aiming at the issues of latency in data processing and the difficulty of capturing short-period, high-frequency disturbances in existing polar motion observation techniques, this paper proposes a measurement method for Earth rotation polar motion based on the joint multi-station observation of high-precision fiber optic interferometers. Firstly, the linear projection equation between the observations of a single-station fiber optic interferometer and the polar motion parameters is derived based on the Sagnac effect, and a mathematical model for multi-station joint least-squares estimation is constructed. Secondly, the influence of the geometric distribution of observation stations on the stability of the solution is investigated, with the Condition Number of the design matrix introduced to quantitatively evaluate the system's performance. For various geographic distribution scenarios, simulation verification is conducted by constructing a complex polar motion physical model that incorporates both Chandler wobble and annual wobble components. The research results indicate that the measurement accuracy of polar motion is highly dependent on the geometric configuration of the observation network. A smaller condition number in the design matrix leads to a stronger suppression of random noise within the system. Compared to the dense distribution scheme (
With the deployment of a new batch of multi-wavelength, multi-messenger survey telescopes, the detection rate of transient sources has been increased significantly. With the discovery of hundreds of thousands of transient sources by these survey telescopes, the existing or planned telescopes are seriously insufficient to achieve all-sky, multi-dimensional (timing, imaging, spectral, polarization), multi-target simultaneous follow-up observations. The development of technologies such as lightweight focusing optics, high-precision deployable mast, and compact focal plane detectors has enabled micro-satellites to possess observational capabilities comparable to those of observatory-level space telescopes. The Chasing All Transients Constellation Hunters (CATCH) propose to deploy a constellation of hundreds of small satellites. Through intelligent distribution and deployment of the constellation, with different satellites configured with different kinds of payloads, CATCH will conduct uninterrupted observations as well as multi-dimensional simultaneous observations for numerous transients using multiple satellites. The key technologies of the CATCH constellation are lightweight focusing optics and compact focal plane detectors.
High-precision space missions, including gravitational wave detection, space-based high-resolution imaging, and advanced propulsion technologies, impose stringent requirements on ultra-quiet and ultra-stable experimental environments, in which low-frequency disturbance suppression is a critical challenge. To address the demands for low-frequency vibration isolation and high-resolution micro-thrust measurement under microgravity conditions, a space science experimental platform based on a high-temperature superconducting (HTS) magnetic levitation composite bearing is proposed in this paper. By exploiting the flux pinning effect and hysteretic characteristics of the HTS magnetic levitation bearing, the platform simultaneously achieves passive low-frequency vibration isolation in the levitated state and ultra-low-friction circumferential rotation. A levitation damping system with frequency-independent hysteretic damping is established, enabling effective suppression of low-frequency disturbances. Power spectral density analysis indicates that the noise level can be controlled below 1 μm/Hz1/2 above 10 mHz. Under space microgravity conditions, the influence of the gravitational unbalance potential well is significantly reduced, and the rotational coefficient of friction is expected to decrease from the order of 10−6 under terrestrial conditions to 10−7~10−8. As a result, long-duration micro-thrust measurements with a resolution of 0.1 μN can be achieved. The proposed superconducting magnetic levitation space experimental platform provides technical support for future high-precision space science experiments, including space electric propulsion performance verification and drag-free control validation.
High-accuracy reference frame transformations for spacecraft precision orbit determination rely on polar motion. To address the 13-day data latency in observed data and the lack of physical mechanisms in traditional prediction models, we propose a fusion prediction method combining Earth rotation dynamics and weighted least squares. This method inverts polar motion series into excitation functions via the Liouville equation, extrapolates them using a weighted least squares model with a time decay factor, and reconstructs predictions via dynamic integration. Experiments using 2019—2023 data demonstrate that this approach outperforms least squares+autoregressive model and International Earth Rotation and Reference Systems Service Bulletin A over 1~365 days, improving accuracy by 43.61%~46.50% and 16.26%~21.08%, respectively. Furthermore, 90-day simulations for navigation satellites such as Global Positioning System and Beidou Navigation Satellite System reveal a 23.97%~35.93% accuracy enhancement over Bulletin A. Results indicate that dynamic constraints effectively mitigate medium-to-long-term divergence, reducing frame transformation errors and supporting high-precision autonomous precision orbit determination and deep space exploration.
A comprehensive understanding of the microbial landscape within space stations is a prerequisite for ensuring space biosafety, enabling precise microbial source tracking, early warning, and efficient elimination. The cornerstone of this endeavor is the establishment of a high-resolution time-series monitoring system for intra-cabin microbial communities. In 2022, the China Space Station (CSS) Habitation Area Microbiome Program was designed to address space biosafety imperatives. It incorporates four core technical components: cultivable strain isolation, longitudinal microbial community monitoring, cross-compartment environmental gradient comparison, and potential-risk identification, thereby providing systematic knowledge support for long-duration crewed missions. This paper presents the characteristic microbes unique to CSS, with Niallia tiangongensis as the representative species. Based on the early-operation “microbe-environment” integrated dataset of the CSS, we integrated resources of cultivable strains, multi-omic big data, cabin environmental parameters, and mission operational metadata to systematically delineate microbial origins, transmission pathways, keystone taxa, and their functional profiles. Furthermore, we mapped out the core technologies and priorities research directions for space microbiology studies that will support high-level missions, including deep-space habitation and lunar surface base deployment. The insights generated by this study will directly inform the formulation and refinement of in-orbit microbial countermeasures, the design of future crewed flight campaigns, and the upgrading of microbial control standards for spacecraft, while offering transferable protocols and data frameworks for microbial management in other sealed extreme environments such as deep-sea submersibles and polar research stations.
During spacecraft operations such as attitude adjustment, orbital transfer, and multiple engine restarts, time-varying thrust often induces sloshing of the propellant inside the tank. This sloshing interacts with the spacecraft structure, leading to rigid-fluid coupled oscillations, which increase the complexity of high-precision control. A key scientific challenge lies in understanding the dynamics of rigid-liquid coupling under microgravity and variable gravity conditions. However, there remains a lack of dedicated experimental platforms and systematic studies for such coupling processes in microgravity environments. To address this gap, a free-sloshing experimental platform has been developed based on the drop tower. The setup consists primarily of a tank and an integrated tank-cage assembly. By applying initial external loads of varying forms and magnitudes, the platform enables the experimental simulation of free-sloshing dynamics in partially filled tanks. This system supports both ground and drop-tower experiments, allowing for studies of rigid-liquid coupling under variable acceleration, and provides valuable microgravity experimental data. The platform helps bridge the gap in experimental capabilities for studying propellant sloshing under microgravity.
With the vigorous development of single-stage orbital insertion, deep space exploration and other technologies, space experimental systems under microgravity conditions have become the research focus of various countries. Space levitation technology can achieve stable suspension of research objects, better simulating the microgravity environment in the space environment, and has gradually become the mainstream technology for ground space experiments. The currently more mature levitation methods include pneumatic levitation, electromagnetic levitation and ultrasonic levitation. A comprehensive summary of these three relatively mature levitation technologies has been made, the research status and levitation principles of the three levitation methods have been detailedly sorted out, and their applications in aerospace engineering have been analyzed in detail: The application scenarios of pneumatic levitation technology include ground testing and manufacturing of spacecraft-related equipment and in-orbit application of dynamic pressure motor devices; the application scenarios of electromagnetic levitation technology include multi-degree-of-freedom magnetic levitation ground test technology, space equipment vibration isolation, wide-speed-range aircraft power system optimization and satellite low-friction attitude and orbit control; ultrasonic levitation is widely used for fuel combustion monitoring in microgravity environments. Finally, some new space levitation technologies have been summarized, and the development direction of future space levitation technology has been proposed, providing certain references for the related research and application of space levitation technology in aerospace engineering.
For the requirement of in-situ utilization of Martian atmosphere resources in future Mars exploration missions, a non-thermal plasma Martian atmosphere oxygen production system was established. Carbon dioxide conversion experiments were conducted using a coaxial dielectric barrier discharge reactor under simulated Martian environmental conditions. This study investigated the effects of key operational parameters such as discharge power and gas flow rate on CO2 conversion and oxygen production rate. It was found that increasing the discharge power could effectively promote CO2 decomposition, and the optimal gas flow rate was determined. In-situ spectroscopic diagnostics were used to examine the species and distribution of molecular and ionic excited states of major gases under different operating conditions. The relationship between working performance and intensities of emission lines was evaluated. The experimental results demonstrate that the coaxial dielectric barrier discharge can effectively convert CO2 under low pressure conditions, providing a valid basis for future engineering applications and potential extension to in-situ production of methane and/or other hydrocarbons.
In deep space exploration missions, the pointing accuracy of high-gain antennas directly impacts the reliability of telemetry, tracking, and command communication, as well as data transmission efficiency. Addressing the technical challenge of in-orbit pointing calibration for high-gain antennas on deep space probes, this paper systematically analyzes the sources of pointing errors and proposes a novel method for calibrating the Earth-pointing direction of high-gain antennas based on the inversion of on-board automatic gain control telemetry data. By analyzing the flight characteristics and constraints of deep space probes, this method adopts a collaborative working mechanism between high-gain and low-gain antennas, providing a systematic solution for in-orbit antenna pointing calibration. Drawing on the engineering practice of the Tianwen-1 Mars orbiter, the design principles, implementation procedures, and error analysis methods of the calibration scheme are elaborated in detail. In-orbit testing demonstrates that this method effectively improves antenna pointing accuracy, with pointing errors better than 0.10°, thereby offering reliable technical support for deep space exploration missions.
As a stable periodic orbital category, distant retrograde orbit (DRO) demonstrates significant application potential in deep space exploration missions. However, their unique thermal environment presents new challenges for spacecraft thermal control design. This study investigates the thermal characteristics of DRO orbits, establishes an external heat flux analysis model, and quantitatively analyzes the intensity and variation patterns of solar radiation, Earth’s infrared radiation, Earth’s albedo radiation, lunar infrared radiation, and lunar albedo radiation. The results indicate that DRO orbits exhibit near-total sunlight exposure. The intensity of Earth-Moon radiation shows nonlinear variations with the Jacobi constant. Comparative thermal simulations between typical DRO orbits and spacecraft in sun-synchronous orbits reveal that DRO spacecraft experience low-frequency large-amplitude temperature fluctuations. These findings provide theoretical foundations and engineering references for future thermal design of DRO spacecraft.
Aiming at the imaging quality degradation of area array cameras caused by satellite-ground relative motion during video imaging of remote sensing satellites, a high-precision and high-stability rotation-free attitude control algorithm for the beam area of video imaging is proposed. This algorithm realizes rotation-free attitude control by constructing a yaw angle calculation model of the beam area through the coordinate transformation method; it establishes a calculation model of the irregular beam area on the ellipsoidal earth’s surface by using the analytical method, providing a reference model for the attitude control technology of video imaging; the attitude controller is designed with the feedforward compensation method to achieve high-precision and high-stability attitude control. Finally, numerical simulations are carried out to verify the accuracy and stability of the algorithm, and an analysis is conducted on the stability of video imaging. The results show that the algorithm can meet the accuracy requirements of video imaging for attitude control.
