## 3. Lunar Communication Challenges  
Scientists encounter a wide range of challenges that demand thorough study and analysis to achieve clear communication without any loss of information (see Figure 1). The moon displays a wide temperature range on its surface. Daytime near the equator can hit 250 \({}^{\circ}\)F (120 \({}^{\circ}\)C, 400 K), nights drop to \(-\)208 \({}^{\circ}\)F (\(-\)130 \({}^{\circ}\)C, 140 K), and a record-breaking \(-\)410 \({}^{\circ}\)F (\(-\)250 \({}^{\circ}\)C, 25 K) was detected at Hermite Crater, making it the solar system's coldest known spot. Thermal investigations indicate that the temperature at Atlas Crater has the potential to exceed 80 \({}^{\circ}\)C during the midday period on the moon. Similarly, frigid areas were located in shadowed craters near the southern pole during winter nights [25; 26; 27]. Furthermore, small impact-created craters are crucial on airless solar system bodies like the moon, which accumulate due to the lack of weathering. Yet, erosion from micrometeorite impacts affects smaller craters [28]. Manual crater detection via visual inspection is impractical due to the moon's numerous small craters. This results in limited databases with either wide coverage of large craters or coverage of craters of varied sizes in a specific area. Expert counting also shows up to 40% of disagreement [28]. Six decades of lunar exploration have yielded only 1675 dated craters out of 9137 recognized. The struggle lies in identifying diverse craters and estimating their ages, complicated by intricate morphologies [29]. Crater environments cause significant signal reflection, resulting in \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Ref**} & \multicolumn{6}{c}{**Models Considered**} \\ \cline{2-9}  & **Free-Space** & **Freznel** & **Reflection** & **Two-Ray** & **Diffraction** & **Irregular Terrain** & **Multipath** \\ \hline [19] & ✓ & ✓ & & ✓ & ✓ & \\ \hline [20] & & & & & ✓ & ✓ & \\ \hline [21] & ✓ & & & ✓ & ✓ & & \\ \hline [22] & ✓ & & & ✓ & ✓ & & \\ \hline [24] & ✓ & & & & & ✓ & ✓ \\ \hline \end{tabular}
\end{table} 
Table 1. Summary of lunar propagation models. Figure 1. Lunar communication challenges. multiple signal copies with different strengths and delays due to diffraction and reflection. These signals include scattered energy, reflections, and direct and diffracted paths, forming a complex channel with attenuation, delay variations, and polarization. The moon's numerous distant craters intensify signal delays, posing challenges for high-data-rate wireless systems. Empirical studies highlight multipath propagation as the primary constraint rather than weak signal strength [24]. The moon's surface is covered by a substantial layer of regolith (fragmented and loose rock material). This regolith results from meteoroid impacts and solar particle bombardment, with varying thicknesses (4-5 m in more regions, 10-15 m in highlands) and sizes, ranging from boulders to dust particles. While \"lunar soil\" and \"regolith\" are often used interchangeably, \"lunar soil\" specifically means the subcentimeter part, but, practically, it usually refers to the submillimeter fraction [30; 31]. The term \"lunar soil\" is misleading as the moon's soil differs significantly from Earth's soil. Lunar soil lacks organic matter and forms mechanically due to meteoroid impact and solar-wind interaction. Unlike terrestrial soils shaped by wind and water, lunar soils are unsorted and characterized by sharp, fresh surfaces. On the other hand, lunar regolith consists of rock fragments, mineral chips, impact glasses, volcanic materials, and a unique moon-specific element known as \"agglutinates\" [30]. Lunar regolith displays varying permittivity and conductivity characteristics depending on its location. These characteristics directly affect the radiation pattern of antennas. Ground reflections introduce multiple peaks and valleys in antenna patterns, leading to signal oscillations.