## 5 Conclusions  
We designed and developed a wireless communication system incorporating a consumer communication IC for expected application to satellite components. The developed communication system was subjected to radiation tests to evaluate its radiation tolerance; the wireless module exhibited sufficient radiation tolerance to withstand the space environment. Using a microcomputer with the same or higher radiation tolerance than that of the wireless module as the module control IC, the complete module can attain sufficient radiation tolerance for application to satellite components.  
Figure 16: CW signal received on the ground.  
Figure 17: FSK signal received on the ground.  
Figure 15: CubeSat WARP-01 in which the developed component was successfully demonstrated.  
The Doppler shift tolerance was investigated considering potential installation on a satellite; hence, it was confined that an FSK signal was received at \(\pm\)38 kHz center frequency in the 435 MHz band, and that unlimited communication could be established, even for an LEO satellite at 400 km altitude, where the Doppler shift effect is large.  
Based on the test results, we developed a satellite component and demonstrated its in-orbit performance as the communication module of an LEO CubeSat (WARP-01) at 400 km altitude. Hence, normal operation was confirmed for both CW and FSK signals, and space utilization of the consumer communication IC was shown to be possible.  
The key outcome was a successful space mission involving the transceiver with the consumer communication IC, which was achieved following sufficient space environment tests, i.e., radiation tolerance and Doppler frequency tests. To exploit the CubeSat mission, rapid development is crucial; therefore, the use of consumer parts and products is unavoidable, not only in our work but for future projects as well. As it is difficult to perform environmental tests, such as radiation tolerance in several institutions, the sharing of information and space application results is crucial. The methodology presented in this paper can be helpful for the advanced evaluation of electrical parts and can contribute to more flexible and advanced system designs using newly introduced devices. As a limitation, production lot differences exist between the test and onboard devices; however, the usage of up-to-date consumer products can enhance and broaden research opportunities compared to persistence with out-of-date products.  
Conceptualization, T.K.; methodology, T.K. and A.N.; software, A.N.; validation, A.N., Y.K. and R.I.; formal analysis, T.K., A.N. and R.I.; investigation, T.K., A.N., Y.K. and R.I.; resources, T.K.; data curation, A.N., Y.K., R.I., P.S., K.K., A.Y. and H.W.; writing--original draft preparation, T.K., A.N. and R.I.; writing--review and editing, T.K.; visualization, Y.K.; supervision, T.K.; project administration, T.K.; funding acquisition, T.K. All authors have read and agreed to the published version of the manuscript.  
This work was supported in part by the Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), Enhancement of National Resilience against Natural Disasters (Funding agency: National Research Institute for Earth Science and Disaster Resilience).  
Not applicable.  
The authors declare no conflict of interest.