# Space Debris In-Orbit Detection with Commercial LiDAR Sensors
## 3 Discussion  
Deploying multiple satellites in the same orbit forming a constellation of satellites can reduce the overall scanning time. This full study introduces the new concept of a Large Cosmic LiDAR (LCL). There is a description of the conceptual design of a Large Cosmic LiDAR in Figure 5.  
This concept can be compared to deploying an enormous radar system circling the Earth. However, instead of using traditional radar, the detection mechanism employs a LiDAR sensor--or constellation of LiDAR sensors--positioned at the sensor's effective detection range within the target orbit. In a Large Cosmic LiDAR, the sensor onboard is able to scan the target orbit with the resolution of the LiDAR's range. The detection system outlined by LCL involves scanning the satellite's orbit while maintaining a constant radial orientation. In this setup, the sensor faces outward from  
Figure 4: The number of years required for a complete scanning as a function of altitude with 10 LiDAR sensors per orbit. Figure 5: Conceptual design of a Large Cosmic LiDAR. the orbit, with the satellite's orientation sustained throughout by the ADCS (Attitude Determination and Control System) onboard the CubeSat. Once all of the characterization of the detection system has been completed and according to the automotive LiDAR sensors currently in the market and summarized in Figure 1, a range below 500 m is quite common for LiDAR sensors with the requirements of being onboard of a small satellite: small size, weight, and power. These sensors can be identified in the table with IDs 1 to 12. Based on the analysis conducted and the information known so far, the LCL system will be designed to achieve a mission duration of 0.5 years for each sensor, which is the typical duration for space missions in low orbits without propulsion systems. Table 1 presents the LCL configuration for each sensor in Figure 1. It includes the Sensor ID, the range, and the number of satellites. The background color of each cell serves as a color code that classifies the LCL system according to the number of satellites in the constellation. Table 2 explains the color code used in Table 1. The background color is green if the constellation has fewer than 5 satellites, orange if it falls between 5 and 10, purple if it is between 10 and 50, and red if it is more than 50. The criterion for choosing the best configuration will depend on the launch possibilities and control of a large number of satellites equipped with the same sensor. The deployment of small satellites in orbit can be just as costly as establishing a single sensor if they can travel on the same launcher. The system becomes more complex if data must be collected from one or many satellites, but this has to be a decision between complexity and costs. There are many possible configurations. It is important to emphasize that detection methodology primarily targets orbital objects that share the same orbital inclination. For objects orbiting with inclinations that differ, traditional one-dimensional sensors are insufficient for detection. To effectively identify such objects, the implementation of three-dimensional sensors onboard or the addition of sensors on alternate CubeSat faces would be necessary. If the satellite exhibits a spin frequency, the scanning also shifts from 1D to 3D. It should be noted that achieving a near 4 pi steradian detection range would theoretically be possible, depending on the satellite's rotational dynamics and sensor configuration. This would require the satellite to rotate so that the sensor field of view covers all directions, but would also significantly increase the complexity of the system due to the contribution of multiple spinning frequencies, the satellite spin, and the sensor spin. The primary preference is to use a single sensor per CubeSat to streamline onboard data management and transmission, thereby reducing system complexity.