# Internet of Spacecraft for Multi-Planetary Defense and Prosperity
## 5 Multi-Planetary Detection, Communications, and Defense: Live Long and Prosper
### Equipping the SCADN with Mitigation Technologies
attaching a mass driver on the PHO to eject material into space to give the PHO a slow steady push and decrease its mass; deploying coherent digging/mining array multiple 1-ton flat tractors able to dig and expel PHO's soil mass as a coherent fountain array [171]; attaching a tether and ballast mass to the PHO to alter its mass center and trajectory; and using magnetic flux compression to magnetically brake and or capture a PHO that contains a high percentage of meteoric iron by deploying a wide coil of wire in its orbital path [172]. The multi-layered architecture of the SCADN network can detect and mitigate the PHO more effectively. On top of a deep understanding of the characteristics of mainstream PHO mitigation technologies, the SCADN framework is equipped with various types of mitigation strategies with several key points unfolded as follows:  
1. Ideally, a hybrid of PHO deflection schemes can be deployed to the spacecraft in each planet's Lagrange points. For example, in remote areas such as around Saturn, Uranus, or Neptune, the low-cost and slow-paced schemes (non-nuclear scheme) can work over an allowable time window that is usually large enough. For example, whenever a space object is detected and determined to be a threat to Earth or other humans' colonization by the SCADN, one or more spacecraft patrolling in the nearest proximity or being able to intercept the PHO on its collision course will be scheduled and coordinated to handle the mitigation. 2. If the situation is so urgent that a fast response is needed immediately, the decision making, resource allocation, task scheduling, and trajectory planning can be fully autonomous, e.g., completely directed by AI/edge-computing, to overcome the large latency in space communication (due to the extremely large space travel distance). The early detection and mitigation will result in lower cost and a higher success rate of mitigation. The power supply can be a hybrid source of nuclear battery and solar panel, while the propulsive devices can be of various types, e.g., cold gas thruster, electrohydrodynamic thruster, electrodless plasma thruster, electrostatic ion thruster, Hall effect thruster, magnetoplasmadynamic thruster, etc. 3. An illustrative description of an exemplary application scenario is presented in Figure 19a, where a space object is detected and identified as having a high probability of impacting Earth within less than one year. The SCADN framework calculates its trajectory (in the red dash line), determines its mass and characteristics, and makes feasible mitigation strategies and plans. Eventually, the SCADN schedules the available spacecraft equipped with suitable mitigation technologies to intercept the object. During this procedure, the spacecraft perhaps need to change its orbit, accelerate or decelerate, which can lead to the consumption of power and thrust on board the spacecraft. In case one spacecraft fails a mitigation task, SCADN can call for multiple spacecraft simultaneously from different orbital locations of different planets to perform the interception. 4. The SCADN framework is capable of computing and mobilizing all available resources within its framework to monitor any space object sensed, estimate the risk, and take the corresponding actions. Such a SCADN framework is supposed to be robust enough that it can still be functional to detect and mitigate the risk even when some spacecraft/survey stations within the framework cannot work properly or human operators are not available. A brief flow chart of the SCADN is given in Figure 19b, where the SCADN framework will utilize all available spacecraft to perform the interception until the impact risk is completely neutralized. Since all spacecraft being able to conduct the mitigation missions are continuously on alert in space, the success rate is largely improved compared to any improvisational interception launch mission from Earth.