The Celestia project was dormant for nearly a decade. It becomes hard to package unmaintained software. I haven’t kept up with who the new owner is or what they’re doing, so there could be reasons it hasn’t been picked up again by the distros.

Back in the late 2000s, Celestia was certainly an amazing experience for me. I see there’s a mobile version now, which makes me happy. It works pretty well on my iPhone, although the UX is not perfect.