What space-related APIs exist out there?

I know open notify API has json files for how many people are on the iss right now, and where it currently is located. These are excellent examples.

I also have NOAA KP Index API which is super interesting too.

NASA open API was a bit too much, and some of them seem dead.

I'm looking for small and easy APIs like these. Will be used as content for educational live coding sessions with teachers.

Do you know of any other such APIs?