Ten-year-old Kai of Hilo, Hawaii, is beyond thrilled that he’s going to be a real astronaut, like his hero Ellison Onizuka. He’s been chosen for a two-year NASA youth mission that will travel to the dwarf planet Ceres, where they’ll also get a good view of Mars. Four other kids will participate: Greg, 13, from Texas; 12-year-old Floridian twins Mary and David; and Keola, 11, from Southern California, with each youngster working on a special research project. Greg’s, for example, involves a time-travel mechanism, and Kai wants to test a device that could sense life-supporting elements and minerals on asteroids. In addition, Kai is bringing his cat, Cappy, to measure how weightlessness affects him, although he receives many warnings that the animal must stay inside his pod (spoiler: he doesn’t). While studying, testing, collecting, and reporting data for individual projects, the young astronauts must work as a team and with adults to address challenges that arise. It’s a learning experience in several ways, testing the kids’ maturity and intelligence. In the end, they earn Capt. Bowie’s praise and look forward to future adventures. Co-authors Jeffries, in her third children’s book, and Bob, in his debut, offer improbably accomplished young characters in this story, but it’s a fantasy that will appeal to any kid who dreams of space exploration. The book fairly vibrates with enthusiasm—and employs many exclamation points—but also takes science seriously, modeling teamwork and depicting realistic problems. A shuttle-door malfunction, for example, is diagnosed by examining a schematic that shows a weak connection—and requires a cool spacewalk to fix it. Rosenberg presents monochrome illustrations with lively compositions that capture the story’s fun.