Kid appropriate chapter books featuring space, scifi or fantasy

I have been reading chapter books to my son, who is 6. We have done some popular kid recommendations (world according to Humphrey, wild robot, charlie and the chocolate factory).

I absolutely love scifi and fantasy, and kid enjoys space. Would love to find some age appropriate books to read to him in those genres. I have the Hobbit in mind, but I remember it having a bunch of songs which kid isn't too into, although I could skip them.

We also tried the boy who grew dragons, but wasn't into it. I'd also like to avoid graphic novels or easy readers (magic tree house). I'd prefer to "save" those for a couple years when hopefully kid will have the reading skills to read those on his own.