## 2 Materials and Methods
### Design of Drive and Control System  
Due to the strict constraints on available space and power in deep space exploration missions, all electronic systems in microchip lasers suitable for planetary mass spectrometry measurements must be customized. The laser operates based on the principle of current injection, inducing particle inversion in the active region. The recombination of electrons in the conduction band and holes in the valence band in semiconductor materials results in stimulated emission, converting electrical energy into optical energy excitation [24]. Therefore, beyond the impact of the structure itself, the stability of the output from the electronic driving system is crucial for the laser's performance. The stability and ripple of the driving current for the semiconductor laser used as a pumping source can alter the optical power, central wavelength, and spectral linewidth of the emitted pump light. For an ideal pump laser, the linewidth should be narrow, the central wavelength stable, and it should have an appropriate photon intensity. This necessitates high stability of the driving current and minimal ripple. Additionally, lasers are highly sensitive to temperature variations. Every 1 \({}^{\circ}\)C fluctuation can lead to approximately 0.2-0.3 nm variation in the pump source's wavelength, accompanied by a noticeable decrease in the lifespan [25]. Therefore, the temperature control accuracy should be less than 0.1 \({}^{\circ}\)C. To mitigate thermal effects during laser operation while meeting low-power usage conditions, this study adopts a controlled constant current source for pulse output. This tailored electronic design ensures optimal performance and reliability of the microchip laser in the challenging conditions of deep space exploration. The electronic driving system comprises a control unit, a pulse constant current source system, a temperature control system, and a protection circuit. The overall structure is shown in Figure 5. The control circuit generates a reference signal, feeding it to the pulse constant current source system and the temperature control system to produce the required current based on the settings. It also engages in communication with the upper computer to monitor the laser's operational status in real-time. The pulse constant current source circuit operates to generate controlled and stable pulse current, facilitating proper laser operation. Simultaneously, the temperature control system upholds the microchip laser's operation under specified temperature conditions. The protection circuit is intricately designed to avert damage to the laser in the event of sudden system issues or abnormal conditions, ensuring the laser's safety and longevity. The control unit is equipped with a high-level anti-radiation microcontroller, and its structure is illustrated in Figure 6. Leveraging the built-in PCA (Pulse-Code Modulation) and DAC0 (Digital-to-Analog Converter), it governs the amplitude, frequency, and duty cycle of the output current. The synthesized reference signal is dispat  
Figure 5: Overall Structure Diagram of Laser Driver System. pulse constant current source system through analog switches, allowing users to adjust the parameters of the output current based on different application scenarios for the laser. DAC1 provides a reference voltage to the temperature control system, facilitating temperature regulation. Two ADC (Analog-to-Digita Converter) channels are employed to collect parameters related to current and temperature, which are then conveyed to the upper computer for display. This sophisticated control unit design ensures precise and flexible control of the microchip laser, adapting to various operational requirements in deep space exploration missions. The pulse constant current source system is depicted in Figure 7, and its operational workflow is approximately as follows: Initially, as the control unit provides the reference signal, the driving voltage (V\({}_{\text{G}}\)) starts to increase gradually from zero.