The Tiny Cyborg — Jill Williamson

Darius is the youngest son of President Cassian. When his father goes missing on a planet with super strong gravity, Darius is determined to rescue him. He makes a dangerous deal with scientist Dr. Fleed to become a cyborg in order to protect his body on the planet's surface. With the help of a robot dog, Darius sets out on his quest. Will he find his father in time? Or will Dr. Fleed take over the solar system and make cyborgs of them all?