# Space Weather Effects on Satellites
## 4 Results
### Space Weather Conditions during Starlink Launches  
We complement our brief literature overview of the SW effects with the analysis of Starlink satellite launches in about three-year period (2019-2022) as listed in Appendix A. We identified first the Dst index at the nearest hour to the launch time, as provided by the Kyoto (provisional and real-time) database, [[https://wdc.kugi.kyoto-u.ac.jp/dstdir/index.html](https://wdc.kugi.kyoto-u.ac.jp/dstdir/index.html)]([https://wdc.kugi.kyoto-u.ac.jp/dstdir/index.html](https://wdc.kugi.kyoto-u.ac.jp/dstdir/index.html)), accessed on 17 August 2023. Based on the Dst values, none of the cases qualified as a GS, as all values were \(\leq-50\) nT. Thus, we increased the time window of interest of about 1-2 days around the spacecraft launch in order to capture any GSs. From the entire list, we selected 15 Starlink launches accompanied by geomagnetic disturbances with Dst index down to \(-25\) nT, Table 2. The threshold is, however, to some degree subjectively chosen. Nevertheless, we do not expect SW effects due to geomagnetic disturbances weaker than this limit. None of the remaining GSs has the double profile and complexity as the case of GSs on 2022-02-03 and 04, described earlier. Some of the launches occur around times of long-lasting but always weak geomagnetic disturbances. Despite the step-like recovery profile, the strongest GS in Table 2 also shows a single drop in the Dst index. We focus on the IP conditions (presence or not of ICMEs, IP shocks and \(B_{2}\)-values) occurring close in time to the Starlink launches. The events are listed chronologically in Table 2. Only six cases have been accompanied by ICMEs, and only four of them have an IP shock with reported speeds ranging between \(\sim\)340 and 820 km s\({}^{-1}\). ICME information is adopted from the online list, [[https://izw1.caltech.edu/ACE/ASC/DATA/level3/icmetable2.htm](https://izw1.caltech.edu/ACE/ASC/DATA/level3/icmetable2.htm)]([https://izw1.caltech.edu/ACE/ASC/DATA/level3/icmetable2.htm](https://izw1.caltech.edu/ACE/ASC/DATA/level3/icmetable2.htm)), accessed on 17 August 2023. IP shock information is collected from the Wind spacecraft, [[https://lweb.cfa.harvard.edu/shocks/wi_data/](https://lweb.cfa.harvard.edu/shocks/wi_data/)]([https://lweb.cfa.harvard.edu/shocks/wi_data/](https://lweb.cfa.harvard.edu/shocks/wi_data/)), accessed on 21 August 2023, due to the larger data coverage of the database. The strongest value (\(-19\) nT) of the southward magnetic field component (\(B_{2}\)) of the interplanetary magnetic field (IMF) is for the Starlink failure case. Interestingly, at the time of the second weakest \(B_{2}\) (\(-6\) nT), we observe the fastest IP ejecta in the list, reaching 820 km s\({}^{-1}\) for the shock speed. The fast (projected) speeds for the incoming ejecta at the Earth are not a determining factor for the GS strength, whereas the GSs (here minor to moderate) are usually related to large values of \(B_{2}\). The \(B_{2}\) component is identifiedfrom the data provided by [[https://omniweb.gsfc.nasa.gov/form/dx1.html](https://omniweb.gsfc.nasa.gov/form/dx1.html)]([https://omniweb.gsfc.nasa.gov/form/dx1.html](https://omniweb.gsfc.nasa.gov/form/dx1.html)), accessed on 17 August 2023. All the IP data is inspected for abrupt changes from about a two-day period before to one day after the spacecraft launch. The exact timings are given in Table 2.  
The magnitude of the \(B_{z}\) does not seem to be an ordering parameters in terms of identifiable ICME at Earth, see Table 2, as the second weakest \(B_{z}\) (\(-6\) nT) is also related to the fastest ICME in our list (\(610\) km s\({}^{-1}\)). The positive trend known to exist between the Dst index and \(B_{z}\)-component is also examined for the above sample and given in Figure 1. Due to the fewer event pairs, the reliability of any type of correlation coefficients (e.g., Pearson, with a value of \(0.52\)) is highly questionable as the scatter plots are subject to statistical noise.