Who is Frank Steinitz from The Engines of God and what is their importance?

Frank Steinitz was the first deep sea mission astronaut. He traveled five Athenas to Saturn in an attempt to stir the imagination of the public and hopefully revive a flailing space program. Frank and the other astronauts in the program had come back with permanent scars, settling the debate about the devastating effects of weightlessness, and returning with tendons and ligaments loosened and muscle that was reduced to slush