# CubeSat-Based Observations of Lunar Ice Water Using a 183 GHz Horn Antenna: Design and Optimization
## 2 Design Methodology  
[PERSON] once said that humanity will one day be faced with a choice between extinction and outer space colonization. The concepts arising from this insightful speech suggest that space colonization is a vital investment for the long-term survival of humanity [30]. As the sun's energy is finite, with estimates suggesting it will die out in the next 5 billion years, it is logical to begin taking preventive measures now to ensure humanity's future [31]. To create life on an extraterrestrial planet, water is a vital element there. Electrolysis of water is a critical resource for supporting life on an uninhabited planet, as it can be used to split oxygen for breathing, hydrogen for refueling spaceship propulsion systems, and for agriculture [29]. According to current technology, human exploration beyond our solar system remains beyond our capabilities. So far, the farthest planet we have successfully reached is Mars, thanks to NASA's landers, and the Moon, visited by NASA's astronauts. Consequently, our options for potential human habitation in outer space are limited to Mars and the Moon. Considering the feasibility of near-future living in outer space, we have chosen to focus on the Moon. We believe that, given the current technological advancements, establishing a human presence on the Moon is more achievable than on Mars. Therefore, directing our efforts toward lunar exploration and colonization seems to be a more practical and realistic goal. In this paper, we propose a system for detecting water on the Moon, an essential technology to facilitate scientific exploration and potentially provide resources for future space missions. The proposed system incorporates a subharmonic mixer spectrometer payload mounted on a CubeSat, aimed at precisely detecting water particles on the lunar surface. This system builds upon our previous work detailed in [29], where we introduced the initial concept. In this current study, we focus on optimizing the payload antenna to enhance the system's performance. By improving the antenna's design, we aim to achieve more accurate and efficient water detection capabilities. This research represents a significant advance ment in our pursuit of harnessing space resources and contributes to the broader goal of enabling human exploration and habitation beyond Earth [32]. There are several techniques for optimizing the performance of a horn antenna. One approach is to design the horn with the correct geometrical dimensions and material properties, such as the size and shape of the aperture, the length of the horn, and the material used for the horn and the aperture. Another approach is to use matching circuits, such as impedance matching networks, to ensure that the antenna is matched to the transmission line, which can improve its efficiency and reduce reflection losses. Additionally, adjustments or modifications may be necessary to mitigate the effects of nearby structures or interference sources. The choice of frequency, polarization, and beamwidth can also impact the performance of the horn antenna, and these parameters may need to be optimized as well. In this paper, we transform the specification of the corrugated horn antenna by the usage of curve fitting algorithms. Firstly, we must plot the 183 GHz corrugated horn antenna regarding to formulas on MATLAB, then simulate the antenna in CST software. After the simulation of the corrugated antenna at CST software, we apply MATLAB spline smooth curve algorithms on corrugated horn antenna geometry and transform the corrugated horn antenna into an identical size smooth-walled horn antenna. At the end of this section, we extract the entry antenna design parameter data. Following section, we undertake the process of smoothing and optimizing the antenna design, by taking this into account we keep antenna specifications for CubeSat remote sensing.