Charles Sheffield is known for the depth and scope of science in his adult science fiction; as if he had added to Asimov's famous line, "To be good science fiction, it must first be good fiction," the reservation, "but it must also be good science."
This charge Sheffield has met even in his fiction for the Tor Jupiter series, with four juvenile novels (Higher Education, The Billion-Dollar Boy, Putting Up Roots, The Cyborg from Earth) released between 1997 and 2003. All four books are enjoyable even for adults, but (and I have the word of my two children here) they are great fun for teens as well.
Higher Education was co-authored by Larry Niven. The story begins in the extremely poor schools of Earth's cities, in which Rick Luban, like other students, is repeatedly given a pass for incredibly bad behavior, until suddenly, one day, he passes over an invisible line and is expelled. Now Rick faces either a grim life of useless poverty on Earth, or being drafted into a program designed to recruit asteroid miners. His choice to take training is his first step into space, and into adulthood. Along the way he and the reader learn some basic physics and astronomy in the easist way possible (as characters in the tale.) Rick's growth from a spotty obnoxious dork to the mature, poised hero is realistic, and (even better for the juvenile reader) is obviously values-based.
The Billion-Dollar Boy is, as many reviewers have pointed out, somewhat a space-fiction Captains Courageous. Shelby Cheever is the eponymous boy who decides that he can pout and tantrum his way to what he wants. In a move to get attention from the staff on his mother's space liner, Shelby lands himself in an outbound ore carrier, on his way to a ship-bound society where a man's name means less than his word (and where Shelby's word has no value). Once again, character growth proceeds along realistic lines: Shelby learns how to negotiate rather than lie, contribute instead of throwing tantrums, and appreciate the value of others' efforts in his behalf.