## 2 Proposed Architecture for Mars Exploration with IoT  
To implement an IoT solution on the surface of Mars using satellite constellations, it is necessary to reconfigure and adapt the architecture currently used in terrestrial satellite constellations [14; 16]. Also, the new architecture must be integrated with the pre-existing communications systems between both planets [11]. As shown in Figure 1, the satellite IoT solution on Earth comprises five fundamental layers [14; 17]. In the first layer, there are IoT nodes, whose function is to acquire data from the physical environment and send it through low-power area network (LPWAN) communications to satellites in LEO. These satellites make up the next layer, consolidate data transmissions, and forward the data received from the IoT nodes to the ground station. In the third layer, the ground station receives the satellite data. It forwards it to the core layer or network server, which monitors and regulates the communications between the IoT nodes and the satellites and performs data ingestion. The network core, or network server, is responsible for transmitting data from IoT nodes to business applications and carries out authentication, authorization, and accounting tasks to ensure adequate security of services. Finally, the last layer is the application layer, which receives data from the satellite network for processing and displays it to the user. In the scenario involving Mars, it is crucial to integrate the IoT satellite communications architecture with the interplanetary communications system. Earth and Mars communicate through orbiters, which act as intermediaries for communication between missions on the Martian surface and ground stations. This helps to improve contact opportunities and direct communication time with Earth [18]. Orbiters in Mars orbit can carry high-gain X-band antennas that provide high-speed communications with Earth [19]. The constellation of satellites can use the orbiter as a relay to transmit data collected by IoT nodes to Earth. Communications between the satellites of this constellation would be carried out through Inter-Satellite Links (ISLs) using S-band frequencies [20]. Consequently, it is essential to characterize the communication dynamics between Earth and Mars to ensure the success of interplanetary communications and, therefore, the adequate support of Martian missions that use IoT technology. This involves considering the relationship between distance, transmission time, and frequency of contacts, considering orbital mechanics and the location of ground stations on Earth. Considering the above, the proposed interplanetary exploration IoT architecture consists of six fundamental layers, as shown in Figure 2:  
* IoT nodes: Refers to the devices and sensors deployed on Mars to analyze atmospheric aspects (e.g., temperature, pressure, gas measurement, and air quality) and geological aspects (e.g., seismic movements). These nodes share characteristics with terrestrial IoT nodes with LPWAN satellite communications, such as long battery life, low cost, and miniaturization. However, they must have enhanced protection against space radiation on Mars compared to Earth [21], as well as the problems associated with dust storms [22], extreme temperature [23], and high space radiation due to the lack of a magnetic field [24] and its tenuous atmosphere [25]. In that sense, the National Aeronautics and Space Administration (NASA) is making significant efforts to adopt IoT for space applications [11]. Figure 1: Satellite IoT terrestrial architecture. * Satellite constellation: The concept refers to satellites designed to meet a common objective, centrally coordinated, and deployed in orbit [26]. Unlike individual satellites, a constellation ensures the simultaneous presence of multiple satellites in different areas of Mars, allowing for extended coverage. These satellites are organized into orbital planes with similar altitudes and angles, which operate as an interconnected network to provide global coverage across the planet [27].