## 2 The \({}^{3}\)ColStar Satellite Mission
### Preliminary Design
#### 2.3.3 On-Board Computer  
An early version of the OBC from [PERSON]'s [71] MISC satellite project [72] is used in the building of the satellite. Executing onboard operations and overseeing communication systems are the OBC's primary responsibilities. The Control and Data Handling (C&DH) subsystem is responsible for managing internal procedures and intersystem communications within the satellite.  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Parameter** & **WHC** & **WCC** \\ \hline Solar Constant (W/m\({}^{2}\)) & 1412.5 & 1321.7 \\ Albedo Factor (\({}^{\circ}\)) & 0.39 & 0.3 \\ Earth’s Effective Temperature (K) & 300 & 250 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Selected parameters for the WHC and WCC cases [68].  
\begin{table}
\begin{tabular}{l c c} \hline \hline
**Payload** & \(T_{min}\) (\({}^{\circ}\)C) & \(T_{max}\) (\({}^{\circ}\)C) \\ \hline OBC & \(-20\) & 70 \\ EPS & \(-40\) & 80 \\ ADCS & \(-40\) & 80 \\ COMM & \(-20\) & 60 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Thermal requirements of satellite subsystems.  
Figure 6: Temperature profiles for WHC and WCC.  
Furthermore, most autonomous software maintains satellite components' operational characteristics, which are critical in executing commands from ground control and processing data for transmission to Earth. OBC development will incorporate cybersecurity measures proposed by NIST [73; 74; 75], and CCSDS [76], leveraging insights from the FACSAT-2 mission [77]. FACSAT-2's key conclusions include a complete review of each component across six operational modes. The addressed issues, such as power constraints, allow for the optimal deployment of resources for high-consumption tasks like X-band communication while optimizing energy utilization during non-sun-tracking modes, especially in penumbral environments [78; 79; 80; 81].  
To protect command and telemetry lines, these precautions include implementing encryption methods and authorization/authentication systems. For this purpose, CCSDS 350.1-G, CCSDS 350.7-G, CCSDS 350.9-G, and CCSDS 3552.0-B [82] are essential reference resources. For this mission, the OBC will consist of the MotherBoard (MB) and the Pluggable Processor Module (PPM), as shown in Figure 7.  
The OBC's ability to withstand single-particle inversions and other radiation-induced flaws is crucial. It uses error detection and correction (EDAC) techniques like memory scrubbing and parity checks, as well as hardware solutions like Triple Modular Redundancy (TMR) and watchdog timers [83]. Backup systems or components provide redundancy, while radiation-hardened parts lessen the likelihood of errors. These safeguards are complemented by software mitigation strategies such as checkpointing and rollback, as well as voting algorithms. Real-time error correction algorithms and hardware are used, and automatic system reconfiguration switches to backup systems or alternate modes when problems are discovered. These solutions ensure that the OBC can successfully regulate and reduce the effects of single-particle inversions, allowing satellites to operate reliably in the hostile space environment [84].  
Figure 7: 3 ColStar OBC architecture.