As terrestrial resources and energy become increasingly scarce and advancements in deep space exploration technology progress, numerous countries have initiated plans for deep space missions targeting celestial bodies such as the Moon, Mars, and asteroids. Securing a leading position in deep space exploration technology is critical, and ensuring the successful completion of these missions is of paramount importance. This paper reviews the timelines, objectives, and associated geotechnical and engineering challenges of recent deep space exploration missions from various countries. Extraterrestrial geotechnical materials exist in unique environments characterized by special gravity, temperature, radiation, and atmospheric conditions, and are subject to disturbances such as meteoroid impacts. These factors contribute to significant differences from terrestrial geotechnical materials. Based on a thorough literature review, this paper investigates the transformation of geomechanical properties of extraterrestrial geological materials due to the distinctive environmental conditions, referred to as the four unique characteristics and one disturbance, and their distinct formation processes. Considering current deep space mission plans, the paper summarizes the geotechnical challenges and research advancements addressing specific mission requirements. These include unmanned exploration and in-situ mechanical testing, construction of extreme environment test platforms, the mechanical properties of geotechnical materials under extreme conditions, the interaction between engineering equipment and geotechnical materials, and the in-situ utilization of extraterrestrial geotechnical resources. The goal is to support the successful execution of China's deep space exploration missions and to promote the development of geomechanics towards extraterrestrial geomechanics.

The Moon is a unique natural laboratory for the study of the deep space plasma and energetic particles environment. During more than 3/4 of its orbit around the Earth it is exposed to the solar wind. Being an unmagnetized body and lacking a substantial atmosphere, solar wind and solar energetic particles bombard the Moon's surface, interacting with the lunar regolith and the tenuous lunar exosphere. Energetic particles arriving at the Moon's surface can be absorbed, or scattered, or can remove another particle from the lunar regolith by sputtering or desorption. A similar phenomenon occurs also with the galactic cosmic rays, which have fluxes and energy spectra representative of interplanetary space. During the remaining part of its orbit the Moon crosses the tail of the terrestrial magnetosphere. It then provides the opportunity to study in-situ the terrestrial magnetotail plasma environment as well as atmospheric escape from the Earth's ionosphere, in the form of heavy ions accelerated and streaming downtail. The lunar environment is thus a unique natural laboratory for analysing the interaction of the solar wind, the cosmic rays and the Earth's magnetosphere with the surface, the immediate subsurface, and the surface-bounded exosphere of an unmagnetized planetary body.This article is part of a discussion meeting issue 'Astronomy from the Moon: the next decades (part 2)'.

With the development of technology and methodologies, Raman spectrometers are becoming efficient candidate payloads for planetary materials characterizations in deep space exploration missions. The National Aeronautics and Space Administration (NASA) already deployed two Raman instruments, Super Cam and SHERLOC, onboard the Perseverance Rover in the Mars 2020 mission. In the ground test, the SHERLOC team found an axial offset (similar to 720 mu m) between the ACI (Autofocus Context Imager) and the spectrometer focus, which would obviously affect the acquired Raman intensity if not corrected. To eliminate this error and, more importantly, simplify the application of Raman instruments in deep space exploration missions, we propose an automatic focusing method wherein Raman signals are optimized during spectrum collection. We put forward a novel method that is realized by evaluating focus conditions numerically and searching for the extremum point as the final focal point. To verify the effectiveness of this method, we developed an Auto-focus Raman Probe (SDU-ARP) in our laboratory. This method provides a research direction for scenarios in which spectrometers cannot focus on a target using any other criterion. The utilization of this auto-focusing method can offer better spectra and fewer acquisitions in focusing procedure, and the spectrometer payload can be deployed in light-weight bodies (e.g., asteroids) or in poor illumination conditions (e.g., the permanently shadowed region in the Lunar south polar area) in deep space exploration missions.