A mod for KSP, originally created by forum user Divico, updated for KSP v1.8.0+ by forum user Stone Blue, and further enhanced(?) by Ted Thompson (TG626).
License: CC Attribution-NonCommercial-ShareAlike 4.0 International aka (CC BY-NC-SA 4.0)
Included Sound Effect (relay.ogg) was obtained under "Royalty-Free License" from videvo.net (identified as Film Projector 25) and as that license provides "There are no limitations on where you can publish your work" and it has been substantially altered by me, I include it in the terms set out above (CC BY-NC-SA 4.0).