Jupiter Pirates: Hunt For the Hydra, by Jason Fry (HarperCollins, Dec. 2013), is the best "kid pirates in space book" I have ever read. Granted, the kids in question would be the first to point out that they are actually privateers, and also granted, I have never before read a book about space piracy/privateering told from the kids' point of view. And I was a tad uncertain, because piracy isn't my favorite fictional thing in the world. But it turns out that the piracy is part of a fun, exciting space adventure that is really solid sci fi, with engaging characters concerned with more than the adventure at hand, and in the end I liked it Lots and recommend it with Conviction.
(Privateering, by the way, is when you do piracy that's sanctioned by your government--you can still attack and pillage ships, but only if they are under enemy flag.)
So in any event, centuries off in the future humanity has sprawled through the solar system, but not amicably--the Jovian Union and Earth, thought not exactly at war at the time of the story, have been in the past. The Hashoone family are privateers of the Jovian Union, capturing Earth ships in true 18th-century piratic fashion, complete with salty nautical terminology. Young Tycho, his twin sister Yana, and their older brother Carlo have spent most of their lives on board the Shadow Comet, learning the family business, and competing with each other--only one of them can inherit the captaincy.
But when an old and clunky earth freighter claims diplomatic immunity from the attentions of the Shadow Comet, Tycho finds himself faced with a problem that's much bigger. And quickly things lead onward through an inter-planetary adventure of great danger and excitement as mystery is added to mystery and then solved with space battling.
Rather than build a future space-faring society from scratch, Fry uses the familiar trappings of pirate ships to good advantage--the world of the Shadow Comet is a familiar place right from the get go, without the need for explanations. Because there's this easy familiarity, with not much overt info dumping, the strange difference of life lived far from earth--like never seeing a blue sky-- spring from the story very vividly.
The characters are great too--though there's sibling rivalry, it's not malicious; though the siblings are smart, they aren't all that brilliant. And it's fun to see a whole family working together--Diocletia, the mother, makes a strong and formidable captain and parent, the father has his own competencies and identity, and Diocletia's father, still a true pirate at heart though he's passed on the captaincy, is a colorful character indeed.
It's easy to imagine this one being very popular with middle grade kids. Here's who I would recommend it too in particular: young readers who in about five years are going to become rabid fans of The Vorkosigan Saga, by Lois McMaster Bujold. I realize this is not as helpful as it might be, but if you've read those books it might give you an idea which kids would like these.
Short answer: Excellent.
Slightly longer answer: it passed the "will this book make the reader forget they are on a bus ride home" test with flying colors. Sigh. Fortunately I live near the end of the line, and the bus turns around and goes back again.....
Here's another review at Views From the Tessearct