# Research on Design, Simulation, and Experiment of Separation Mechanism for Micro-Nano Satellites
## 3 Design of the Separation Mechanism  
### Overall Design  
The MF satellite's separation mechanism is tube-shaped, and the entire structure is box-symmetrical. As illustrated in Figure 3, the separation mechanism is mainly composed of the bottom plate, deployment spring, push board, upper guide rail, lower guide rail, side panel, door cover, opening and locking module for the door cover (OLMDC), and locking and releasing module for the door cover (LRMDC). The bottom plate, upper guide rail, lower guide rail, side panel, and door cover form the separation mechanism's primary load-bearing structure. The ejection system is composed of a deployment spring and a push board. Through the use of an electromagnet, the LRMDC mechanism achieves power-on unlocking and power-off locking. The LRMDC mechanism is non-explosive, has no impact, and can be reused on the ground many times. The separation mechanism's primary load-bearing structure is made of aluminum alloy 2A12 due to its high strength, low density, low cost, and ease of manufacture. The upper and lower guide rails are integrated with the strengthening rib, which is simple to process and assemble and helps maintain the guide rails' parallelism. The guide rails are hard anodized to prevent cold welding between the satellite's guide rails and to provide a smooth surface for the MF satellite's deployment. Due to optimization of the design, the separation mechanism weighs only 5.8 kg. The mass ratio of the satellite to the separation mechanism is only 0.29, significantly less than the mass ratio of the conventional separation mechanism, which significantly reduces launch costs.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**NO** & **Index Name** & **Index Value** \\ \hline \multirow{2}{*}{1} & \multirow{2}{*}{Structural parameters} & Size (mm) & \(\leq\)400 \(\times\) 500 \(\times\) 550 \\  & & Mass (kg) & \(\leq\)6 \\ \hline \multirow{2}{*}{2} & \multirow{2}{*}{Separation attitude} & Separation velocity (m/s) & 0.5–2 \\  & & Separation angular velocity(\({}^{\circ}\)/s) & \(\leq\)3 \\ \hline \multirow{2}{*}{3} & \multirow{2}{*}{Natural frequency} & 3 axis (Hz) & \(\geq\)50 \\ \hline \multirow{2}{*}{4} & \multirow{2}{*}{Overload} & Lateral direction(g) & 3 \\  & & Vertical direction(g) & 10 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Indexes for separation mechanism.  
Figure 3: Exploded view of the separation mechanism.  
As illustrated in Figure 4, the outer envelope of the separation mechanism is 343.5 mm \(\times\) 470 mm \(\times\) 516.3 mm in the launch state and 343.5 mm \(\times\) 675 mm \(\times\) 945 mm in the on-orbit state. Above the guide rails on each side, an additional 50 mm of space is available to accommodate solar panels, a camera hood, and antennas. The length of the guide rail can be adjusted via the satellite's guide rail. The MF satellite is inserted into the separation mechanism along the guide rail. The rotational hinge joint in the OMLDC can be used to close and open the door cover. The satellite is in contact with the wedge compression points and the four guide rails of the separation mechanism, which restrict the satellite's vertical movement. The door cover and push board act as horizontal restrictions on the satellite. Eight screws secure the separation mechanism to the carrier launch vehicle. When the MF satellite reaches orbit, the separation mechanism detects the separation signal, the LRMDC releases the door cover, and the OMLDC opens the door cover. Under the action of the deployment spring, the MF satellite will slide out along the guide rail of the separation mechanism. When the door is opened to a certain angle, it is locked in place by the spring positioning pin to prevent it from bouncing back and interfering with the MF satellite in the event of a collision.