Preface

Startups and rocket manufacturers are revolutionizing access to space. For example, Aerojet Rocketdyne, NASA, and SpaceX partially (and increasingly) use 3D-printed elements in rocket building, which lowers costs and allows for faster construction of engines. The number of low Earth orbit (LEO) micro-gravity scientific experiments conducted by the International Space Station is already in the thousands. This year, the first set of circumlunar commercial missions will be launched, opening a vastly more diversified point of view on the possibilities to make the moon our first non-Earth planetary port. Although the multiple challenges of lunar habitats and periodic/long-term crew rotations are still many, science and technology, alongside commercial drives, are changing the convergence rate on a first landing/settlement date.

There are still many open scientific questions about the moon, and there are also now many questions about humans and their potential lives there. This book looks at the history of the moon orbit and the prospects of in situ lunar science, the radiation impact on the lunar surface, the resistance of settlement materials on the moon under the conditions of protecting humans on-site, and the preparation of humans for space missions.

> **Dr. Yann-Henri Chemin** Joint Research Centre, Ispra, Italy

Section 1 Introduction
