Search

China has successfully launched six lunar probes so far. From Chang’E-1 to Chang’E-4, they completed the circling, landing and roving exploration, of which Chang’E-4 was the first landing on the far side of the Moon in human history. Chang’ E-5 was launched in December 2020, bringing back 1731 g of lunar soil samples. Through the detailed analysis of the samples, the scientists understand the history of late lunar volcanism, specifically extending lunar volcanism by about 800 million to 1 billion years, and proposed possible mechanisms. In addition, there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon. China’s first Mars exploration mission Tianwen-1 was successfully launched in July 2021. Through the study of scientific data, a number of important scientific achievements have been made in the topography, water environment and shallow surface structure of Mars. This paper introduces the main scientific achievements of Chang’E-4, Chang’E-5 and Tianwen-1 in the past two years, excluding technical and engineering contents. Due to the large number of articles involved, this paper only introduces part of the results.

The Direction of Arrival (DOA) parameter is a key parameter in directional channel modeling for GNSS systems and multipath suppression. However, achieving high-precision, low-complexity DOA estimation of multiple signal sources without requiring a known source number is still a challenge. This paper introduces a satellite navigation DOA parameter estimation method based on deconvolution beamforming. By exploiting the translational invariance property of the uniform linear array pattern, the deconvolution process is applied to the de-spread array pattern of satellite navigation signals, achieving high-precision estimation of DOA parameters. This method can achieve high-precision blind DOA estimation of multiple signal sources while significantly reducing the estimation complexity. Compared with traditional methods, precise DOA estimation can be achieved even in low-signal-to-noise-ratio conditions and with a small number of elements in the array. The theoretical analysis and simulation results verify the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Context. Space weathering alters the surfaces of airless celestial bodies, thereby modifying their spectra significantly. Olivine plays a crucial role in responding to space weathering on silicate planets. However, the spectral variations that occur in olivine with varying iron content as a result of space weathering conditions remain unclear. Aims. We aim to systematically characterize the spectral variability of surface iron-rich olivine in the space weathering environments of Phobos and the Moon. Methods. We conducted nanosecond pulsed laser irradiation experiments on a set of synthetic Fe-rich olivine (Fa29, Fa50, Fa71, and Fa100). The energy levels were simulated for Phobos and the Moon. We analyzed the available near-infrared (NIR) spectroscopy. Results. We find that olivine with higher Fe content undergoes stronger weathering under the same irradiation energy, shifting absorption centers around 1.08 µm and 1.35 µm to longer wavelengths. When comparing the high energy and low frequency, spectral changes are more pronounced at low energy and high frequency. The olivine with the same iron content exhibits a more noticeable shift around 1.08 µm under various irradiation levels, while the band center around 1.35 µm remains stable. Conclusions. When the same amount of radiation energy is received, changes in the spectrum are more noticeable at low energy and high impact frequency than at high energy and low impact frequency. The absorption position at ~1.35 µm is a good indicator of the Mg# value of space-weathered olivine. [ABSTRACT FROM AUTHOR]