I am sorry for your loss, and I am sure "Rocket Cat" is now happy where it is.

Cats (and animals in general) definitely belong to family, and it is always a hard time when they decide to leave us for new horizons where we cannot follow them. Mine, who became later my mom's cat when I left Belgium, decided to leave us right before the pandemic at roughly the same age as yours. 17 years add up to being quite a full life for a cat, that I guess it has been a happy life with you (of which you will hopefully keep a lot of memories).

Take care!