Avengers of the Moon — Allen Steele

Curt Newton has spent most of his life hidden from the rest of humankind, being raised by a robot, an android, and the disembodied brain of a renowned scientist. This unlikely trio of guardians has kept his existence a closely guarded secret after the murder of Curt's parents.

Curt's innate curiosity and nose for trouble inadvertently lead him into a plot to destabilize the Solar Coalition and assassinate the president. There's only one way to uncover the evil mastermind -- Curt must become Captain Future.