## 2 Proposed Architecture for Mars Exploration with IoT
* Orbiter satellite: The orbiter satellite acts as a communication link between the Martian surface and the Earth and is located 300 km above the Martian surface [28; 29]. Given the distance between Mars and Earth, the direct signal that equipment such as rovers can send is weak, so the orbiters act as signal amplifiers to retransmit them with greater intensity to Earth. They use X-band frequencies to provide a stable and reliable connection with Earth [30]. * Ground station: This refers to the antenna located on Earth to receive communications sent by the Martian orbiter. This station is part of the existing infrastructure for communications with Mars orbiters [30] and acts as a bridge with the terrestrial communications infrastructure. The information from the IoT nodes received by the ground station is forwarded to the core or network server. * Core or network server: The network server is in charge of processing, storing, and forwarding satellite data to external applications [17], such as data visualization tools. In the case of LPWAN communications, it manages the authentication, validation, and provisioning of IoT nodes in the network. The processed data are then sent via an application programming interface (API) to applications used by scientists. * Scientific applications: These are applications used by scientists or companies to analyze and study data collected by IoT nodes or other instruments on Mars, such as Java Mission-planning for Analysis and Remote Sensing (JMARS) for atmospheric data analysis [31]. Section 5 of this work details the main applications that can be developed on Mars with this technology, considering the lines of research currently underway or planned to be carried out in the future. IoT nodes and systems must be designed and tested meticulously to ensure their reliability and performance even under extreme conditions. They use materials and components that resist radiation and the vacuum of space [22]. To prevent operational problems, internal thermal control and specific protection systems are implemented [11; 23]. Error mitigation techniques are also implemented to ensure the integrity of transmitted data. For terrestrial IoT nodes, hardware-level adaptation can be conducted through dust protection systems, internal thermal control, and protection against space radiation. NASA is currently conducting studies in this area [11]. The feasibility of using electronic devices based on Commercial Off-the-Shelf (COTS) has become a central issue in space mission planning [32]. It has proven to be a transformative strategy to reduce costs and accelerate development timelines. An example of this is the Ingenuity helicopter, which operates on the surface of Mars. It has two cameras and a telecommunications module that depends on COTS components. The Mars Science Laboratory mission also included these components  
Figure 2: Interplanetary exploration IoT architecture. in the propulsion and parachute systems to guarantee a precise and safe landing [33]. These components are increasingly used in deep space exploration missions [34]. They benefit from advances in miniaturization, energy efficiency, and signal processing. This allows for the construction of smaller, lighter satellites and probes with increasingly greater capabilities and operational autonomy. As shown in Figure 3, communications between IoT nodes and the satellite constellation in Mars orbit can have two communication models: Direct-to-Satellite IoT (DtS-IoT) and Indirect-to-Satellite IoT (ItS-IoT) [35]. In DtS-IoT communication, IoT nodes communicate directly with the constellation without an intermediary. On the other hand, ItS-IoT needs a gateway that centralizes all communications from nearby IoT nodes. This gateway collects data from IoT nodes and transmits it to the orbiting satellite constellation. Current rovers can be proposed as LoRa gateways for exploration on Mars since they currently act as gateways between sensors and drones with the Earth, such as the Ingenuity helicopter [36].