We've had this book for many months. When we first tried to read it to our toddler/preschooler, he didn't get halfway through. Since then he's learned more about space from other sources, and lately he's been requesting this book a lot and seems to like it pretty well. It introduces the basics of space travel like rockets, astronauts, satellites, travel to the Moon, and the like. If it's your child's very first exposure to space concepts, this might not be the best book for the purpose. Otherwise, it's good.
As to reading level, we have many beginning reader books that are divided into levels 1, 2, 3, etc. I wouldn't call this level 1 on anybody's scale--level 2 maybe. It is more advanced in its use of language than series like the "Little Bear" or "Biscuit." It's also much more conceptually advanced than those books.
If I had any complaints it would just be that the production is a little too slap-dash. Don't get me wrong, I'd buy it again and we'll keep reading it, but there are a lot of little things that could be better.