This affects questions 1-7. Later questions using the Fireball data set work fine.
Can someone please verify and perhaps correct the issue?
I solved it, the Autograder was just being very particular, instead of defining a “planets” expression, just using CloudGet inline worked:
CloudGet["http://wolfr.am/7FxLgPm5"][All, "Moons", Max, "Mass"]
I just stumbled across this one, too. Sometimes, the autograder in this package is doing pure magic. Other times, it’s kinda dumb.
I give huge props to anyone who makes it through all the chapters/exercises in this course. It’s a huge swath of knowledge.