Books in the Billy Jones - Space Cadet series

When 11 year old Billy Jones discovers his Dad is really a secret spaceman who works on the moon, to avoid a galactic diplomatic incident he becomes the first human child to go to space school.  However, not all aliens are friendly.  The sinister alien Darkmites hate humanity and secretly plot the Earth's destruction.  With his new, strange, friends, can he save the World from being destroyed and not get expelled?