## 2 Materials and Methods
### Description of the Software Developed and Used for the Analysis of the Results  
The information sent by the AztechSat-1 and received by the GlobalStar gateways is transmitted in a custom format, needing the development of a computer program to automatically count, categorize, and decode the received messages. AztechSat-1 transmits various parameters such as temperatures of different solar panels, battery voltage, current, and other relevant data. The system data dictionary, providing a comprehensive list of these parameters, can be found in Table 2.  
Figure 4 shows the nanosatellite received packets using the GlobalStar link throughout the entire mission. The chart provides a summary of packets categorized by their size in bytes. The transmission rate of messages is grouped into sets of 9-byte packets, with each transmission containing 1 to 16 packets. This allows a maximum of 144 bytes to be transmitted in a single uninterrupted burst. The geographic distribution of the AztechSat-1 packets is shown below in Figure 5 using GlobalStar communication.  
Figure 4: Received packets categorized by size (in bytes).  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Subsystem** & **Description of Parameters** & **Unit or Expected Value** \\ \hline Radio & Power amplifier temperature & tenth of \({}^{\circ}\)C \\  & Last Received Signal Strength Indicator & RSSI \\  & Background RSSI & RSSI \\ \hline EPS & Power converters voltage—Array [3] & mV \\  & Battery voltage & mV \\  & Current in—Array [3] & mA \\  & Boost converters current & mA \\  & Battery’s output current & mA \\  & Output current—Array [4] & mA \\  & Output channels status—Array [4] & 0 or 1 \\  & I2C watchdog time left & 32-bit number (Seconds) \\  & GND watchdog time left & 32-bit number (Seconds) \\  & Watchdog reboot number & 32-bit number \\  & Temperature sensor & \({}^{\circ}\)C \\ \hline OBC & Temperature Sensor & \({}^{\circ}\)C \\  & Pulse Width Modulation (PWM) current & Ma \\  & Last OBC reboot cause & 32-bit number \\  & Magnetometer—X axis & 32-bit float number \\  & Magnetometer—Y axis & 32-bit float number \\  & Magnetometer—Z axis & 32-bit float number \\  & Gyro—X axis & 32-bit float number \\  & Gyro—Y axis & 32-bit float number \\  & Gyro—Z axis & 32-bit float number \\ \hline Payload & Number of Channel & 8-bit number \\  & Number of Bursts & 8-bit number \\  & Minimum Burst Interval: Units of 5 s. & 01h to 3 Ch \\  & Maximum Burst Interval: Units of 5 s. & (5 to 300 s) \\  & Maximum Burst Interval: Units of 5 s. & (02 h to 78 h \\  & Status flags & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\ \end{tabular}
\end{table}
Table 2: Description of transmitted parameters categorized by subsystem.  
For the ground station-based system, the AztechSat-1 nanosatellite utilized a half-duplex radio operating at a UHF frequency that was compatible with the ASM + Golay protocol and offered Gaussian Frequency Shift Keying (GFSK) modulation options. The communication with the onboard computer was facilitated through the I2C communication protocol. The nanosatellite was equipped with a 50-ohm matched omnidirectional antenna, providing a gain of 1.5 dBi at \(-1\) dBi. The use of UHF made it possible to collect data from the university's ground station and the SatNOGS network.  
Throughout the operational period of AztechSat-1, SatNOGS received a total of 500 beacon packets. These packets were subsequently processed to extract and interpret the information they contained. On 10 December 2021, the AztechSat-1 nanosatellite reentered Earth's atmosphere, which is evidenced by numerous reports of telemetry available on Twitter and SatNOGS. In Figures 6 and 7 the altitudes and speeds of the last days in orbit of the nanosatellite can be observed.