A research group led by Prof. SHENG Zhigao from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, has discovered mirror symmetry triggered chiral phonon behavior and a giant magneto-optical modulation in the two-dimensional material AgCrP₂S₆ with space- and time-symmetries.

Large-scale Low Earth Orbit (LEO) constellations have become a focal point for providing round-the-clock high-fidelity information services. However, their efficient and economical batch deployment faces severe challenges from growing demands and multiple constraints, with existing methods struggling to address the computational complexity in large-scale scenarios. To meet this pressing need, this study published in the Chinese Journal of Aeronautics proposes an innovative deployment optimization framework. At its core, it constructs a novel partial time-expanded network and employs an efficient hybrid algorithm to significantly reduce constraint explosion, enhancing solution efficiency and scalability. The framework supports dual-channel, multi-configuration rocket strategies and flexible deployment under multiple mission triggers through weighted optimization. Ultimately, it effectively reduces deployment costs, improves optimization efficiency, and provides reliable decision support for large-scale constellation deployment.

The positioning, navigation, and timing (PNT) information is fundamental to modern information systems. Over the years, people have invented many navigation systems to get PNT information, whereas each single navigation system has its flaws. As far as radio navigation is concerned, besides global navigation satellite systems (GNSS), exploiting non-navigation signals of opportunity for navigation under complex environments has attracted more and more interest in recent years. Satellite signals of opportunity positioning (SSOOP) attempts to work out a navigation solution with many non-GNSS satellite signals, such the many low-earth-orbit direct-to-cell and broadband satellite communications signals, when GNSS signals are not available. It is promising in addressing GNSS vulnerability by using an overwhelming quantity of satellites with diverse signal formats, multiple radio bands, and global availability. However, existing work on SSOOP is still quite preliminary. No work on identifying the passing satellite has been done when a receiver powers on without a rough guess on its location.

Accurate estimation of the ionosphere is essential for reliable Global Navigation Satellite System (GNSS) positioning, timing, and space weather applications. 

Due to the unique conditions of the space environment and abundant resources, the field investigation and study of the Moon, Earth’s sole natural satellite, represent a crucial milestone in China’s forthcoming deep space endeavors. The successful collection of lunar soil by the Chang’E-5 mission signifies the next phase of the lunar exploration program, which aims to establish a preliminary research station on the lunar south pole. Highly adhesive fine dust particles with an adhesion strength of 0.1 to 1.0 kN/m², which originate from the regolith, disperse throughout the lunar surface. These particles exhibit a lasting attraction and subsequent persistent adhesion to the surface of spacecraft or spacesuits. The accumulation of highly adhesive dust on spacecraft presents a serious issue to hinder long-term extravehicular activity and the establishment of a permanent station on lunar surface. In contrast to the immediate physical damage caused by hypervelocity (> 1.0 km/s) impacts, this adhesion observed at low- velocity (0.01 to 100 m/s) collisions can more unobtrusively and mortally degenerate the performance of equipment. In recent years, many interaction models have been developed to forecast the adhesion and ejection dynamics of lunar dust on various surfaces. Most researches on the electrostatic force applied on dust particles near the surface use point-charge approximation. Although this simplification makes the simulation easier, the error can be large due to the polarization of dust induced by the image charge.

Discover how space–ground fluid AI is set to revolutionize 6G networks by integrating edge AI with satellite systems, enabling global AI services and overcoming challenges of satellite mobility and communication rates. Explore the innovative techniques proposed in a new study published in Engineering that could shape the future of intelligent connectivity.

There are over 36,500 pieces of space debris of larger than 10 cm in orbit according to statistical model orbit provided by European Space Agency’s Space Debris Office at European Space Operations Centre in Darmstadt, Germany. Any of those debris can pose a threat to operational satellites. Active debris removal (ADR) is conducted to solve the above problems for stabilizing the space debris environment. Unfortunately, the angular velocity of space debris exceeds the maximum angular velocity of 4 to 5 deg/s that can be directly captured by a robotic arm. Therefore, to stabilize the debris environment, the first task, i.e., de-tumbling tasks, is to reduce the initial angular velocity of the debris by applying an external torque. To ensure the safety of the de-tumbling tasks avoiding collision between the de-tumbling device and the uncooperative space target, many contactless methods have been studied. Among them, the contactless method based on electromagnetic eddy current method has received increasing attention due to the advantages of pollution-free and high safety performance.