# Impact of Mega Constellations on Geospace Safety
## 4 Impact of Starlink on Control Avoidance Strategies for low-orbiting Satellites in Geospace
### Impact on ACPL Values for LEO Space Target Satellites
In Figure 8c,d when the manipulation frequency is the smallest in the two comparison groups, the corresponding risk coefficient is 0.681 with a risk of 4.35 \(\times\) 10\({}^{-5}\) when the manipulation frequency is 6.88 \(\times\) 10\({}^{-4}\) without considering Starlink, and the corresponding risk coefficient is 0.254 with a risk of 1.73 \(\times\) 10\({}^{-3}\) when the manipulation frequency is 0.131 when considering Starlink. Furthermore, the corresponding risk coefficient is 0.372 when the manipulation frequency is 190.4-times of the previous one in the two comparison groups. Manipulation frequency at the minimum, the risk coefficient becomes 0.372-times after the manipulation frequency becomes 190.4-times the previous one, and this comparison group data shows that when the manipulation frequency increases across orders of magnitude, its corresponding risk coefficient can be reduced compared to the previous one, but the effect is weaker and not proportional to the growth of the manipulation frequency, i.e., the consumption is too great for half the effort. In Figure 8e,f we choose a more moderate manipulation frequency, i.e., the manipulation frequency corresponding to ACPL-10\({}^{-4}\). The risk coefficient corresponding to a manipulation frequency of 0.0809 is 0.0112 with a risk of 2.63 \(\times\) 10\({}^{-6}\) when Starlink is not considered. The risk coefficient corresponding to a manipulation frequency of 1.68 is 0.192 with a risk of 1.65 \(\times\) 10\({}^{-4}\) when Starlink is considered. With 1.65 \(\times\) 10\({}^{-4}\), the risk coefficient becomes 17.143-times greater after the manipulation frequency becomes 20.77-times greater than the previous one, a data set that corroborates the fact that the corresponding risk coefficient still grows with a similar multiplication when the manipulation frequency grows insignificantly. One thing the above data show is that increasing operating frequency after taking Starlink into account does not guarantee that the risk coefficient decreases or even returns to the original tier; in the case where the increase in operating frequency is not of a large order of magnitude, the risk coefficient is even larger than before, indicating that the overall risk magnitude increases, and the residual risk is operated even if it is 10% of the original risk. It is further exhibited that even if the number of orbit avoidance controls is significantly higher than before Starlink is considered, it will still face a worse geospace environment. Figure 8: Average number of operations vs. residual risk. (**a,b**) The variation of GAOFEN satellites in fractional risk and risk to different Mean Number of Avoidance Manoeuvres With Starlink and Without Starlink; (**c,d**) The variation of CORVUS BC5 satellites in fractional risk and risk to different Mean Number of Avoidance Manoeuvres With Starlink and Without Starlink; (**e,f**)The variation of YAOGAN-35C satellites in fractional risk and risk to different Mean Number of Avoidance Manoeuvres With Starlink and Without Starlink. From the preceding discussions, it can be deduced that Starlink has an impact on the target satellites due to the large number of satellites dispersed across their entire orbit, and that the degree of impact corresponds to the degree of flux variation. When ACPL-\(10^{-4}\) is selected, when comparing to the case without Starlink, the avoidance frequency of GAOFEN satellites increases by a factor of 2.252, and the collision risk with or without Starlink is 2.27 \(\times\)\(10^{-6}\) and 1.27 \(\times\)\(10^{-5}\) respectively. However, the risk increases to 5.5947-times greater than the previous one. CORVUS BC5 with its ACPL-\(10^{-4}\) has increased its avoidance frequency by a factor of 13.9, with a collision risk of 1.22 \(\times\)\(10^{-5}\) and 5.4 \(\times\)\(10^{-5}\), respectively. While changing the risk to 4.5-times greater than the previous one, while maintaining the ACPL-\(10^{-4}\), indicating an increased avoidance frequency. However, again the risk is shown to increase rather than decrease.