K. H. Joy

Orbital data indicate that the youngest volcanic units on the Moon are basalt lavas in Oceanus Procellarum, a region with high levels of the heat-producing elements potassium, thorium, and uranium. The Chang’e-5 mission collected samples of these young lunar basalts and returned them to Earth for laboratory analysis. We measure an age of 1963 ± 57 million years for these lavas and determine their chemical and mineralogical compositions. This age constrains the lunar impact chronology of the inner Solar System and the thermal evolution of the Moon. There is no evidence for high concentrations of heat-producing elements in the deep mantle of the Moon that generated these lavas, so alternate explanations are required for the longevity of lunar magmatism.

The Rocks That Hit the Moon The cratered surface of the Moon bears witness to the numerous impacts it has suffered. Chemical signatures of these impacts have been detected indirectly. Now, Joy et al. (p. 1426 , published online 17 May; see the Perspective by Rubin ) report the detection and characterization of meteorite fragments preserved in ancient lunar regolith breccias from the Apollo 16 landing site. These meteoritic fragments represent direct samples of the population of small bodies traversing the inner solar system at around 3.4 billion years ago—the same time or just after the basin-forming epoch on the Moon.

A high-level overview of current research in the area of lunar regolith excavation and handling for In Situ Resource Utilisation (ISRU) is presented. Thirteen processes are grouped into discrete and continuous excavators. A further differentiation is made between systems with and without connection to a mobility platform – referred to as complete and partial systems. For each group, a set of representative performance parameters has been identified and compared, while special characteristics or limitations are highlighted. The present work identifies a need for high detail research into the development of reliable and efficient excavation systems, due to the high importance of regolith excavation and handling to ISRU. A need for more standardised information and recording of specific data during supporting experimental studies is made apparent. In order to enable easier categorisation, comparison, and evaluation of future concepts, a set of key performance parameters requiring consideration during experimental campaigns is described and the importance of their inclusion underlined.

The lunar geological record contains a rich archive of the history of the inner Solar System, including information relevant to understanding the origin and evolution of the Earth-Moon system, the geological evolution of rocky planets, and our local cosmic environment. This paper provides a brief review of lunar exploration to-date and describes how future exploration initiatives will further advance our understanding of the origin and evolution of the Moon, the Earth-Moon system and of the Solar System more generally. It is concluded that further advances will require the placing of new scientific instruments on, and the return of additional samples from, the lunar surface. Some of these scientific objectives can be achieved robotically, for example by in situ geochemical and geophysical measurements and through carefully targeted sample return missions. However, in the longer term, we argue that lunar science would greatly benefit from renewed human operations on the surface of the Moon, such as would be facilitated by implementing the recently proposed Global Exploration Roadmap.