Return to the Moon: New perspectives on lunar exploration.

Lunar exploration is deemed crucial for uncovering the origins of the Earth-Moon system and is the first step for advancing humanity's exploration of deep space. Over the past decade, the Chinese Lunar Exploration Program (CLEP), also known as the Chang'e (CE) Project, has achieved remarkable milestones. It has successfully developed and demonstrated the engineering capability required to reach and return from the lunar surface. Notably, the CE Project has made historic firsts with the landing and on-site exploration of the far side of the Moon, along with the collection of the youngest volcanic samples from the Procellarum KREEP Terrane. These achievements have significantly enhanced our understanding of lunar evolution. Building on this success, China has proposed an ambitious crewed lunar exploration strategy, aiming to return to the Moon for scientific exploration and utilization. This plan encompasses two primary phases: the first crewed lunar landing and exploration, followed by a thousand-kilometer scale scientific expedition to construct a geological cross-section across the lunar surface. Recognizing the limitations of current lunar exploration efforts and China's engineering and technical capabilities, this paper explores the benefits of crewed lunar exploration while leveraging synergies with robotic exploration. The study refines fundamental lunar scientific questions that could lead to significant breakthroughs, considering the respective engineering and technological requirements. This research lays a crucial foundation for defining the objectives of future lunar exploration, emphasizing the importance of crewed missions and offering insights into potential advancements in lunar science.

The origins of colour patterns in fossil insects revealed by maturation experiments.

Many fossil insects show monochromatic colour patterns that may provide valuable insights into ancient insect behaviour and ecology. Whether these patterns reflect original pigmentary coloration is, however, unknown, and their formation mechanism has not been investigated. Here, we performed thermal maturation experiments on extant beetles with melanin-based colour patterns. Scanning electron microscopy reveals that melanin-rich cuticle is more resistant to degradation than melanin-poor cuticle: with progressive maturation, melanin-poor cuticle regions experience preferential thinning and loss, yet melanin-rich cuticle remains. Comparative analysis of fossil insects with monotonal colour patterns confirms that the variations in tone correspond to variations in preserved cuticle thickness. These preserved colour patterns can thus be plausibly explained as melanin-based patterning. Recognition of melanin-based colour patterns in fossil insects opens new avenues for interpreting the evolution of insect coloration and behaviour through deep time.

Surges in volcanic activity on the Moon about two billion years ago.

The history of mare volcanism critically informs the thermal evolution of the Moon. However, young volcanic eruptions are poorly constrained by remote observations and limited samples, hindering an understanding of mare eruption flux over time. The Chang'e-5 mission returned the youngest lunar basalts thus far, offering a window into the Moon's late-stage evolution. Here, we investigate the mineralogy and geochemistry of 42 olivine and pyroxene crystals from the Chang'e-5 basalts. We find that almost all of them are normally zoned, suggesting limited magma recharge or shallow-level assimilation. Most olivine grains record a short timescale of cooling. Thermal modeling used to estimate the thickness and volume of the volcanism sampled by Chang'e-5 reveals enhanced magmatic flux ~2 billion years ago, suggesting that while overall lunar volcanic activity may decrease over time, episodic eruptions at the final stage could exhibit above average eruptive fluxes, thus revising models of lunar thermal evolution.

Fusible mantle cumulates trigger young mare volcanism on the cooling Moon.

The Chang'E-5 (CE5) mission has demonstrated that lunar volcanism was still active until two billion years ago, much younger than the previous isotopically dated lunar basalts. How the small Moon retained enough heat to drive such late volcanism is unknown, particularly as the CE5 mantle source was anhydrous and depleted in heat-producing elements. We conduct fractional crystallization and mantle melting simulations that show that mantle melting point depression by the presence of fusible, easily melted components could trigger young volcanism. Enriched in calcium oxide and titanium dioxide compared to older Apollo magmas, the young CE5 magma was, thus, sourced from the overturn of the late-stage fusible cumulates of the lunar magma ocean. Mantle melting point depression is the first mechanism to account for young volcanism on the Moon that is consistent with the newly returned CE5 basalts.

In situ detection of water on the Moon by the Chang'E-5 lander.

We report analysis results of the reflectance spectra (0.48 to 3.2 µm) acquired by the Chang'E-5 lander, which provides vital context of the returned samples from the Northern Oceanus Procellarum of the Moon. We estimate up to 120 parts per million (ppm) of water (OH + H2O) in the lunar regolith, which is mostly attributed to solar wind implantation. A light-colored and surface-pitted rock (named as CE5-Rock) is evident near the lander. The reflectance spectra suggest that CE5-Rock could be transported from an older basalt unit. CE5-Rock exhibits a stronger absorption, near 2.85 µm, than the surrounding regolith, with estimation of ~180 ppm of water if the model for estimating water content of regolith is applicable to rock samples, which may suggest an additional source from the lunar interior. The low water content of the regolith may suggest the degassing of mantle reservoir beneath the Chang'E-5 landing site.

GAUSS - genesis of asteroids and evolution of the solar system: A sample return mission to Ceres.

The goal of Project GAUSS (Genesis of Asteroids and evolUtion of the Solar System) is to return samples from the dwarf planet Ceres. Ceres is the most accessible candidate of ocean worlds and the largest reservoir of water in the inner Solar System. It shows active volcanism and hydrothermal activities in recent history. Recent evidence for the existence of a subsurface ocean on Ceres and the complex geochemistry suggest past habitability and even the potential for ongoing habitability. GAUSS will return samples from Ceres with the aim of answering the following top-level scientific questions: What is the origin of Ceres and what does this imply for the origin of water and other volatiles in the inner Solar System?What are the physical properties and internal structure of Ceres? What do they tell us about the evolutionary and aqueous alteration history of dwarf planets?What are the astrobiological implications of Ceres? Is it still habitable today?What are the mineralogical connections between Ceres and our current collections of carbonaceous meteorites?

A dry lunar mantle reservoir for young mare basalts of Chang'e-5.

The distribution of water in the Moon's interior carries implications for the origin of the Moon1, the crystallization of the lunar magma ocean2 and the duration of lunar volcanism2. The Chang'e-5 mission returned some of the youngest mare basalt samples reported so far, dated at 2.0 billion years ago (Ga)3, from the northwestern Procellarum KREEP Terrane, providing a probe into the spatiotemporal evolution of lunar water. Here we report the water abundances and hydrogen isotope compositions of apatite and ilmenite-hosted melt inclusions from the Chang'e-5 basalts. We derive a maximum water abundance of 283 ± 22 µg g-1 and a deuterium/hydrogen ratio of (1.06 ± 0.25) × 10-4 for the parent magma. Accounting for low-degree partial melting of the depleted mantle followed by extensive magma fractional crystallization4, we estimate a maximum mantle water abundance of 1-5 µg g-1, suggesting that the Moon's youngest volcanism was not driven by abundant water in its mantle source. Such a modest water content for the Chang'e-5 basalt mantle source region is at the low end of the range estimated from mare basalts that erupted from around 4.0 Ga to 2.8 Ga (refs. 5,6), suggesting that the mantle source of the Chang'e-5 basalts had become dehydrated by 2.0 Ga through previous melt extraction from the Procellarum KREEP Terrane mantle during prolonged volcanic activity.

Isobaric Spike Method for Absolute Isotopic Ratio Determination by MC-ICP-MS.

Absolute isotopic ratios are required for isobaric interference corrections, spike calibrations, and isotopic analysis by external normalization methods. However, high-precision natural isotopic abundance data are lacking for many elements, particularly those with less than four isotopes or having isobaric isotopes with other elements. In this study, we developed a method for absolute isotope ratio analysis, which integrates the concept of the double-spike method with isotopic analysis of element pairs that have isobaric isotopes. Using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS), the isotopic composition of a sample can be derived by measuring a series of mixtures of the sample and a spike element that has an isobaric isotope with the element being analyzed. We applied this method to five pairs of elements (Ca-Ti, V-Ti, Cr-Ti, Ni-Zn, and In-Sn) and obtained the absolute isotopic ratios for Ca, V, Cr, Ni, and In, as well as the relative Ca isotopic composition. By simultaneous measurement of Ti and Ca isotopes, a quantitative relationship between the instrumental mass fractionation factors and element masses was developed. After correcting for the difference in instrumental mass fractionation factors, the obtained absolute ratios agree well with the literature data and have per mil level accuracy. This method has considerable potential in measuring the absolute isotopic ratios of elements that have isobaric isotope with other elements. Such precisely determined absolute isotopic ratios and the relationship between the instrumental mass fractionation factors and elemental masses will improve isobaric interference corrections, particularly when chemical purification is imperfect or during laser ablation analysis.

Microplastics in a wind farm area: A case study at the Rudong Offshore Wind Farm, Yellow Sea, China.

Despite the rapid construction of offshore wind farms, the available information regarding the risks of this type of development in terms of emerging pollutants, particularly microplastics, is scarce. In this study, we quantified the level of microplastic pollution at an offshore wind farm in the Yellow Sea, China, in 2016. The abundance of microplastics was 0.330 ±â€¯0.278 items/m3 in the surface water and 2.58 ±â€¯1.14 items/g (dry) in the sediment. To the best of our knowledge, the level of microplastic pollution in our study area was slightly higher than that in coastal areas around the world. The microplastics detected in the surface waters and sediments were mainly fibrous (75.3% and 68.7%, respectively) and consisted of some granules and films. The microplastics in the samples might originate from garments or ropes via wastewater discharge. The abundance of plastic in the water and sediment samples collected from the wind farm area was lower than that in the samples collected from outside the wind farm area. The anthropogenic hydrodynamic effect was the main factor affecting the local distribution of microplastics. The presence of a wind farm could increase the bed shear stress during ebb tide, disturbing the bed sediment, facilitating its initiation and transport, and ultimately increasing the ease of washing away the microplastics adhered to the sediment. This study will serve as a reference for further studies of the distribution and migration of microplastics in coastal zones subjected to similar marine utilization.