**4.2 Human health, its requirements and limitations in space and on the Moon**

Surface/elevation mapping, exosphere, radiation and volatile composition are the main subjects of interest for governments involved in lunar science, besides the engineering proof of work for orbital control, landing automation and sample return. Its lack of atmosphere also brings advantages to astronomical observation, more so with a large distributed array [26]. The Moon surface is in itself a human health issue, from the micro particulate size of the Moon regolith and its toxicity

<sup>1</sup> At the time of the editing of this manuscript (May 2022), the state of the Russian-lead presence in space is undefined and will certainly be delayed on many planned ventures. The 307th ESA HQ meeting press conference is found here (https://www.youtube.com/watch?v=P1Yox7Jmzlk) with elements provided on stopping all collaborations with Russia.

[27]. Indeed, the lunar environment has detrimental impacts on the human organism [28], but as found in the Global Exploration Roadmap (**Figure 7**; [29]), the Moon environment and astronauts in transits have much less to fear on the Moon base than in deep space or on a 3-year return mission to Mars. Here, we note in **Figure 7** about fractional Earth gravity that the impact of even a fraction of Earth gravity is highly beneficial on the human health. Indeed, only 1/10–1/2 of Earth gravity would suffice to bring considerable health benefits to humans, whether on the Moon, Mars or within the artificial gravity of a rotating spacecraft.

Most of the orbiting space stations study human health and adaptation to micro-gravity. PRC's TianHe core module launched end of April 2021, the station's environment is studying mutation breeding, medicines and new materials. After 6 months in orbit, a taikonaut returned to Earth 18th May 2022, enabling study of the effect of micro-gravity on the longest period in space for a woman.

Similarly, the ISS is running a large number of scientific experiments on a rotating basis, recently, the Dragon Crew-1 had a Multi-purpose Variable-G Platform (MVP) Cell-06 experiment dedicated to Cartilage–Bone–Synovium (CBS) Micro-Physiological System (MPS) Investigation. This particular experiment is vital to low-gravity adaptation of CBS system. It is especially dealing with the problematic recovery from trauma that happened in space or on the Moon due to its microgravity compared to our Earth-adapted bodies (**Figure 8**).
