In modern literature there are clearly defined roles for what SF is and is not, I don’t necessarily agree with it but you can almost see the Hugo nominees from a mile away. There isn’t any way that a book like this could get published now any more than a book like 'A Princess of Mars' could. 1950s SF was full of books aimed at young kids about space and aliens in an almost wholesome fashion. While the children involved with these sort of stories might be involved in danger it was more of the Saturday morning cartoon variety than the 'Hunger Games' sort. A lot of reviews for this novel actually criticize it for being too heavy on math for young kids, which I think is ridiculous. Kids love math.
For me this book gets classified with a lot of other pulp SF from the '50s and earlier. It's a good example of what the genre was about and where it was heading. It shows some of genre's roots in the sort of space adventure, alien punching, that you expect when you think classic SF. Also the novel had a strong female protagonist that didn't take a back seat to a man or become a damsel in distress, always a plus in my book and especially admirable considering when the book was written.