# Concept of a 3D-Printed Voronoi Egg-Shaped Habitat for Permanent Lunar Outpost
## 1 Introduction  
Looking to the starry sky, man has always longed to stand on the surface of the Moon. However, starting from 4 October 1957, the dream began to become a reality. A new era of space exploration began, when the Soviet Union sent the first artificial satellite Stputnik to the Earth's orbit [1; 2]. Man stepped on the surface of the moon on 16 June 1969 as part of American Apollo 11 mission. No one thought at the time that the last step taken by the crew of Apollo 17 on 19 December 1972 would be the last for the next decades. Currently, NASA plans to return and land a human crew by 2024 and permanently inhabit the Moon in the future. However, NASA is not the only institution or country which has such intentions. China (among other countries) and private companies such as SPACEX and BLUE ORIGIN also strive for the Moon [3; 4; 5; 6]. European Space Agency developed Terrae Novae 2030+ Strategy Roadmap [7], whose main long term goals for Europe are defined as follows: capability to launch and deliver payloads to ISS as laboratory for technology demonstration, and to be able to deliver these technologies to the Moon and Mars. Poland is an example of a relatively small country with lunar ambitious. The Polish Space Agency is a part of the Artemis Accord program and has its own plans for Moon exploration. Polish scientists are working on different aspects related to prospective exploration and further utilization of lunar surface. The investigations of future orbiter payload able to detect troilite on lunar surface are described in [8]. The developed surface payloads are presently able to detect mechanical properties of lunar soil with the capability to reach 5 m depth in lunar regolith [9]. The technology of lunar surface exploration is based on drilling systems [10] and sampling systems [11]. The latter is currently under investigations to reach technology readiness level 6. In this context, several campaigns were organized in Poland to better understand the lunar regolith [12]. From the perspective of future lunar surface utilization, economic aspects, intellectual property issues, and space law questions are of great importance [13]. Ideas for establishing a base on the Moon have been around since the early days of the space program. Many questions arose regarding the functionality, use, shape, and transport of the material, and assembly of the habitat [13]. A big breakthrough happened recently when 3D printing technology appeared, which completely opened up new possibilities for working with the shape and processing of material on site. NASA's ultimate goal is to get to Mars. In order to achieve this, many procedures and technologies need to be tested on the nearest neighbour--the Moon. The Artemis mission is to test new technologies, land a man on the Moon, and establish a base there. The base would also serve as a transfer station and actively provide support for missions to Mars. The major components of the program are the Space Launch System (SLS), Orion spacecraft, Lunar Gateway space station, and the commercial Human Landing Systems, including Starship HLS. The entire lunar surface is covered by regolith, which is the unconsolidated layer of granular material and has been generated over time due to the pulverization of rocks by meteorite and micro-meteorite impacts [14]. To create a permanent base, strategic raw materials (e.g., water, metals, and oxygen) are needed. Possible water deposits were found in the regions of the South Pole [15]. Metals and oxygen can be extracted from regolith at the lunar South Pole [14]. There are more craters in these places, and due to their position and depth, sunlight never reaches the bottom of craters. At the same time, this location is advantageous for long-term foundations thanks to the constant sunshine. Even though the Sun moves just above the horizon in these regions, its radiation is not weakened, as is the case on Earth where it is limited by the atmosphere.