China Astronaut Research and Training Center

Correction on: Xu Z, Yang C, Wu F, Tan X, Guo Y, Zhang H, Wang H, Sui X, Xu Z, Zhao M, Jiang S, Dai Z, Li Y. Triple-gene deletion for osteocalcin significantly impairs the alignment of hydroxyapatite crystals and collagen in mice. Front Physiol. 2023 Mar 28;14:1136561. doi: 10.3389/fphys.2023.1136561. PMID: 37057181; PMCID: PMC10089303.The original version of the Article contained errors in the Discussion, Paragraph 2: "This is the first study to examine the effects of deleting all three Ocn genes in mice with a C57BL/6J genetic background". A correction has been made to the section: "This is the first study to examine the effects of deleting all three Ocn genes in mice with a C57BL/6 substrain background ". The original version of this article has been updated.

DLR and ESA are jointly operating the Moon analogue facility LUNA in Cologne, Germany, to provide a venue for end-to-end testing of instruments, experiments, procedures and operations in a controlled, standardized environment. The facility consists of a large-scale testbed filled with mare regolith simulant EAC-1A, nominally to a depth of 60 cm, but extending to 3 m in the so-called deep-floor area (DFA), as well as a smaller dust lab filled to about 60 cm depth with the Lumina250 highland simulant. Both simulants have been characterized with a focus on mineralogical and geological properties, but for EAC-1A, lab data on shear-wave velocities as well as electric properties are also available. For both of these properties, compaction, which is in-situ unknown, plays an important role.Here, we report on the first attempts of in-situ characterization of the elastic properties of EAC-1A in LUNA by 12 single-station ambient vibration measurements that were analysed in terms of the H/V spectral ratios. In addition to a peak at 0.76 Hz consistently observed at all locations that is related to local geology (sediment-bedrock interface at about 150 m depth), measurements in areas covered by the regolith simulants show additional high-frequency peaks between 12 and 55 Hz, dependent on regolith thickness. As the regolith thickness at each measurement location is known, the common trade-off between layer velocity and thickness in the inversion of the H/V peak frequency is resolved and measurements at different regolith thicknesses can be used to constrain the vertical velocity profile of EAC-1A. However, the task is complicated by strong surface topography as well as the structure of the DFA and buried exploration targets within, which could potentially result in 2D and 3D site effects for some measurement locations. Hence, careful data selection based on the directivity of the observed H/V peaks is performed. First results indicate very similar velocities for both mare and highland simulants, pointing to the dominant effect of granular texture as compared to chemical composition.We compare fits to the data for different types of velocity laws and also discuss our results in light of the laboratory measurements as well as in comparison to in-situ data from the Moon.

Why AC2E?The AC2E initiative is based on several comments from scientists working in the MLT region regarding the potential impact from re-entering space debris burning up in the mesosphere. Furthermore, increasing numbers of orbital launches might have exhaust effects on the MLT region.The initiative will focus on the possible impacts caused by the emerging large constellations of satellites. Hence, it’s of vital importance to start a monitoring program as early as possible to secure baseline data before too many constellations are in orbit and the re-entering mass increases exponentially.The mesosphere is sometimes referred to as the "new ocean" since in earlier times, people considered items dropped into the ocean as something they didn’t need to worry about anymore. It “disappeared”. These days we know much better.Only in January 2025, 120 Starlink satellites burnt in the atmosphere. According to an ESA report, in 2022, more than 200 tons of metal particles were introduced into the atmosphere, in 2024, it was already 800 tons. Until 2040, more than 60.000 new satellites are predicted to be launched into orbit. This might lead to the disposal of up to 10.000 tons of Al2O3 / year into the atmosphere. Especially the upper atmosphere is very vulnerable for two reasons. Due to its low density, mass contribution has a much bigger effect. 1 ton of material in the MLT region equals up to 100.000 tons in the troposphere.What is AC2E? The “AC2E” is an international collaboration effort targeting advancement in specific, fundamental issues in space and earth science. The concept was conceived and developed between 2024 and 2026 by Andøya Space (ASP), Esrange/SSC and DLR MORABA.The main aim for AC2E is to set up a repetitive monitoring program providing measurements in the Mesosphere / Lower Thermosphere (M/LT) at regular intervals by any means possible, but in a systematic and standardized way. Thus, providing regulatory bodies with relevant background information for decision making.The projected timeframe of 2027 to 2037 is specifically chosen to align the initiative with the upcoming Solar Cycles 26 and 27, which have a large influence on the dimensions and characteristics of Earth’s atmosphere and its interaction with space objects. Such background information must be based on as much pristine and unmodified data as possible.Possible science topics Atmospheric Pollution from Re-entry: As satellites demise, they burn up and release materials (e.g., aluminum, titanium, composites) into the MLT. Sounding rockets equipped with sensitive instruments can:· Identify and quantify new types of artificial aerosol layers resulting from satellite re-entry.· Investigate the chemical reactions of these materials with the ambient atmospheric constituents.· Assess the potential impact on natural metal layers and MLT chemistry, including ozone.Influence on NLCs/PMCsLocalized Atmospheric PerturbationsImpacts of Orbital Rocket Launches

The lung, a key organ for oxygen exchange, is particularly susceptible to high-altitude hypoxic stress. Hypoxia induces vascular impairment, which is characterized by vascular inflammatory responses and aging-like changes. Lipid metabolism has been shown to be closely associated with cellular homeostasis and membrane balance. However, the alterations in pulmonary lipid metabolism in response to high-altitude hypoxia are not fully characterized. In this study, model mice were subjected to a hypobaric chamber at an altitude of 5500m for 3 days, and pulmonary microvascular endothelial cells (PMVECs) were cultured under 1% oxygen for 18h to simulate the effects of acute severe hypoxia. High-altitude hypoxia significantly disrupted lung sphingolipid metabolism, accompanied by inflammation and aging-like changes in mice. Moreover, C24-Ceramide (Cer) and its synthase (CERS2) were significantly increased in PMVECs. C24-Cer was identified to bind to voltage-dependent anion channel 1 (VDAC1) (a mitochondrial outer membrane protein), which promoted mitochondrial DNA (mtDNA) release and subsequently induced the inflammation and aging-like changes by activating the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway. Inhibition of C24-Cer or VDAC1 oligomerization by si-Cers2 or VBIT-4 could significantly reduce mtDNA release and alleviate inflammation and aging-like changes in the PMVECs and lung tissue under hypoxia. Our present work provides a novel and potential therapeutic target for high-altitude hypoxia-related vascular diseases.

Long-term spaceflight composite stress (LSCS) can induce detrimental impacts on the human central nervous system, leading to conditions such as depression. This study aimed to identify mechanisms of simulated LSCS-induced spaceflight depression and the protective effects of traditional Chinese medicine Baoyuan Jieyu Formula (BYJYF) on spaceflight depression rats. The present study simulated the real long-term space station environment by conducting a 6-week experiment that involved simulating microgravity, isolation, noise, circadian rhythm disruptions, and low pressure. Glutamatergic neuron firing in hippocampus of the rats was examined by patch clamp to explore the effects of simulated LSCS exposure and BYJYF intervention on neurons. Single-cell RNA sequencing was then conducted to reveal the underlying mechanisms of simulated LSCS-induced spaceflight depression and the efficiency of BYJYF intervention. Results showed that simulated LSCS caused glutamate overload, induced by an abnormally high release frequency ( P < 0.05) from glutamatergic neurons. Single-cell sequencing revealed that the possible causes of glutamate overload lied in the reduction in hippocampal stromal cells, especially astrocytes, thereby delaying glutamate clearance, which could be mitigated by BYJYF intervention by up-regulating the proportion of stromal cells. Transcriptomics revealed that the target pathway of simulated LSCS-induced spaceflight depression was the calcium signaling pathway, and BYJYF functioned by regulating genes related to long-term potentiation pathway. Taken together, we demonstrate the target pathways of simulated LSCS-induced spaceflight depression and the potential clinical application of BYJYF, opening up broader prospects for the application of traditional Chinese medicine in space medicine.

Guidance poses a significant issue in aerospace vehicle development. Simultaneous impacts and higher lethality necessitate constraints on impact time and angles, posing a substantial obstacle to effective guidance law design. Similarly, the flexibility and maneuverability of aerospace vehicles, which require a designable acceleration profile, are equally essential issues in guidance law design. Therefore, to overcome the limited selectable constraint ranges and the challenges of shaping acceleration profiles in existing guidance laws, without sacrificing their penetration and cooperation capabilities, a three-stage catenary-based guidance law is proposed that considers constrained impact and robustness to external disturbances. To begin with, the desired launch angle and initial velocity direction of the catenary are enforced during the first stage, which uses a circular arc. Subsequently, the impact time constraint is met in the second catenary-based stage, and the final stage employs an additional circular arc to enforce the desired impact angle. Using the proposed analytical geometric rules, trajectory parameters are determined explicitly. Meanwhile, a robust guidance law is developed, with all constraints met. The proposed guidance law requires no numerical calculations, nonlinear model linearization, or reliance on time-to-go error estimation, making it convenient to implement. Furthermore, the proposed guidance law extends the range of available time constraints from the minimum to infinity and the range of angle constraints from 0 degrees to 360 degrees, thereby addressing the issue of a wide range of spatiotemporal multi-constraints. The adaptability issue arising from an extensive range of impact time constraints and arbitrary angle constraints is addressed by a shapeable acceleration profile, enabling the maximum acceleration value or peak time to be adjusted to meet mission requirements. Various disturbed-engagement scenarios are simulated, and numerous analyses are conducted to evaluate the effectiveness and robustness of the proposed sliding mode control guidance law.

Accurate and efficient data-driven prediction of embedded airborne load separation trajectories and attitudes can not only significantly improve the safety of the separation process but also substantially reduce reliance on costly aerodynamic simulations and wind tunnel testing. This paper proposes a real-time condition fusion Transformer (RCF-Transformer) model for predicting the trajectory and attitude after load separation. Using wind-tunnel datasets of separation events obtained from Captive Trajectory Simulation (CTS), the model encodes historical sequence information while dynamically injecting real-time input conditions measured at the moment of separation into the decoder. Masked multi-head self-attention and cross-attention mechanisms are employed for collaborative learning, enabling multi-step, multi-output prediction of three-axis position and attitude. Experimental results show that, for a multi-step prediction horizon of up to T=5, the proposed model achieves an overall prediction accuracy of 95.28%. Furthermore, error-structure analyses based on Theil’s inequality coefficient decomposition, confidence intervals, and F-tests of residual variances demonstrate that the residuals are dominated by nonsystematic, high-frequency fluctuations and that the performance gains over the strongest baseline are statistically significant. These results indicate that the proposed method is highly stable and robust, providing an efficient and scalable data-driven solution for safety monitoring and decision support during the initial separation of airborne loads.