# Development of a Novel Deployable Solar Panel and Mechanism for 6U CubeSat of STEP Cube Lab-II
## 3 A PCB-Based High-Damping Deployable Solar Panel Module
### Solar Panel Holding and Release Mechanism  
Figure 5a,b illustrate close-up views of the proposed three-pogo pin-based mechanism in fully and partially stowed solar panel states, respectively. The mechanism comprises pogo pins, electrical interface PCB, brackets, Dyneema wire, resistor, and resistor PCB. [PERSON] et al. [23] and [PERSON] et al. [24] investigated the applicability and effectiveness of two pogo pins in HRM, although the main purpose of using three pogo pins in the proposed mechanism is to simplify the electrical circuit by reducing the electrical components to lower the cost of the product and increase its reliability for secure release action in a harsh space environment. The main design driver for the use of the pogo pin (MP511-1111-E03100A, CFE Corporation Co., Guangdong, China) [25] connectors is the establishment of a secure electromechanical connection between the electrical interface PCB and the resistor PCB integrated at the edge of the CubeSat structure and solar panel edge, respectively. The pogo pins provide electrical current to the resistor mounted on the resistor PCB during mechanism activation. The holding constraint on the solar panel at the stowed state is achieved by tightening the Dyneema wire on the brackets. Mechanical restraint in the in-plane direction of the solar panel during the stowed configuration is accomplished by ball and socket joints made on the brackets that act as a mechanical limiter to avoid the adverse panel strike on pogo pins beyond the pogo pin's plunger working stroke range. Additionally, the socket limits ball movement within a nominal gap, which averts the burden at the wire knot under vibration environments. To release the holding constraint on the solar panel, a resistor (3216 SMD type, Walsin Technology Co., Taipei, Taiwan) [26] was  
Figure 4: Integration process of a stiffeners on the PCB panel. integrated on the resistor PCB as an actuator. As the mechanism is activated by the power supply in an electrical circuit, the resistor cuts the tightened wire. The panel deployment is initiated instantly by the compression force of the pogo pin plunger, 0.68 \(\pm\) 0.19 N, which could rapidly or simply interrupt the circuit path to the resistor. Consequently, the hinge torsional forces deploy the solar panel to its intended angle. Table 5 lists the specifications of the hardware used in P-HRM. Figure 6a,b illustrate the electrical system of the three-pogo pin-based mechanisms. For mechanism activation, the input voltage on the electrical circuit path to the resistor was applied to 8V, although the electrical components were supplied at 3.3 V. The optocoupler  
Figure 5: Configurations of three-pogo pin-based HRM: (**a**) solar panel fully stowed and (**b**) solar panel partially stowed. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Items** & **Details** & **Value** \\ \hline \multirow{8}{*}{Pogo pin} & Manufacture & CFE Corporation Co. \\ \cline{2-3}  & Voltage and current (V, A) & 12, 3 \\ \cline{2-3}  & Max. electrical contact resistance (m\(\Omega\)) & 50 \\ \cline{2-3}  & Life test (Cycle) & 100,000 \\ \cline{2-3}  & Qualification temperature range (\({}^{\circ}\)C) & \(-\)40 to 85 \\ \cline{2-3}  & Spring force (N) & 0.68 \(\pm\) 0.19 \\ \cline{2-3}  & Total length (mm) & 9 \\ \cline{2-3}  & Full stroke (mm) & 1.4 \\ \cline{2-3}  & Working stroke (mm) & 1.0 \\ \hline \multirow{8}{*}{Wire} & Manufacture & YGK \\ \cline{2-3}  & Material & Dyneema \\ \cline{2-3}  & Diameter (mm) & 0.205 \\ \cline{2-3}  & Max. allowable force (N) & 88.2 \\ \hline \multirow{8}{*}{Resistor} & Manufacture & Walsin technology Co., Taipei, Taiwan \\ \cline{2-3}  & Package & SMD Type \\ \cline{2-3}  & Electrical resistance (ohm) & 4.7 \\ \cline{2-3}  & Resistance tolerance (\%) & \(\pm\)1 \\ \cline{2-3}  & Max. power dissipation (W) & 0.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Specifications of the hardware used in the three-pogo pin-based HRM.