NASA Space Place is good site sponsored by…NASA.
It has lots of very accessible info about all things space-related and, with a click on the globe on the top right of the English or Spanish page, it will take you to the version in the other language.
I’m adding it to The Best Sites For Learning About Planets & Space.
I’m also adding it to The Best Multilingual & Bilingual Sites For Math, Social Studies, & Science.
You might also be interested in The Best Resources For Helping Beginner ELLs Learn About Space & Planets.