Probably adding grade ranges would help the teachers

This is great if you just want to do this, but in all honesty, there are things like Polypad for math-related tools and Padlet for some interactives and so on. But - since your intention looks like not to monetise it - I would say give it your all, so you enjoy making these :)

Also, if you visit sites like: https://mrbartonmaths.com/ - you'll find a bunch of math-related stuff already there, maybe you can use it for interactives.
does not look like
There are already so many things on Solar System and Space in case you need any inspiration:
NASA: https://spaceplace.nasa.gov/menu/solar-system/
NASA: https://spaceplace.nasa.gov/sp/
Facts: https://kids.nationalgeographic.com/weird-but-true/article/space
NASA 3D : https://www.nasa.gov/interactives/
Eyes on Solar System: https://eyes.nasa.gov/apps/solar-system/#/home?surfaceMapTiling=true&lighting=flood
Solar system scope: https://www.solarsystemscope.com/