The Rising Flame — Sylvia Engdahl

Book One: Defender of the Flame
Starship pilot Terry Radnor is elated to be among those chosen to defend the secret colony Maclairn against enemies who pose a threat to the spread of paranormal human mind powers. He commits himself wholly to the goal of that world, not guessing how far his effort to protect it will take him from everything else he cares about--his promising career as a Fleet officer, his wife and soulmate, his unborn child. Torn away against his will, he is forced into exile from all that has previously mattered to him, without hope of a chance to fulfill the pledge he has made. Yet a mysterious and extraordinary destiny has been predicted for Terry, and fate leads him to an even dtranger one than anybody could have imagined.

Book Two: Herald of the Flame
As captain of his own starship Estel, Terry Steward, born Terry Radnor, is committed to spreading acceptance of psi powers and other advanced mind capabilities throughout the colonies of humankind. Barred from contact with Maclairn, he now journeys from world to world, heralding the hopeful future about which he alone knows the full truth. But the opponents of mind-power are gaining strength, and on Earth the persecution of people who develop new abilities is increasing. Soon targeted by bounty hunters, Terry risks everything that matters to him in a desperate attempt to defeat Maclairn's enemies, not guessing that if he lives long enough, he is destined for an even greater role in human history than he has played as a defender of its cause.