The GPS satellites bus is listed under GPS, GPS II, GPS IIA, GPS IIF, and GPS IIR. It looks like a bug that the Payload isn't showing up. I see one as GPS SVN 10. I may be only showing payloads where there are at least 2 with the same name - otherwise there would be a dropdown that is 30,000 long.

Love your suggestion to improve the search feature to be more like the main search dropdown. Adding it to the list of to-dos on the github issues.