Voyagers II: The Alien Within (Ben Bova Series)
The Return: Book IV of Voyagers (The Grand Tour 20)
Voyagers (Ben Bova Series Book 1)
The Exiles Trilogy
New Earth (The Grand Tour Book 21)
The Star Conquerors
Powersat (The Grand Tour Book 1)
Mars Life (The Grand Tour Book 18)
Empire Builders (The Grand Tour Book 3)
Forward in Time