Another thought crowded in. Why such high speed? That was something over which there was no choice. The protective atmosphere had to be left swiftly. The speed was added to at every opportunity. It was possible to slow down only at the last moment. Otherwise....
Otherwise what?
There was no escape from the conclusion—otherwise heredity was altered and mutations would result. Marlowe sat back. This was true without exception. It was the biggest factor that controlled the conditions of interplanetary flight. But—
They'd had their children!
Marlowe's pulse increased. As training director, he'd learned not to leap at things that merely looked good. He had to examine them carefully. But—well, it was a new approach, though he couldn't really expect anything from it. There was more to a crew than a pilot, more to space flight than one incredible lucky voyage, for angels took vacations, too.
"You weren't on duty at all times," Marlowe pointed out. "Then there's navigation."
"Don't sleep much," said Ethan. "Catnap once in a while." He thought it over. "When I did sleep, 'Mantha helped out." He looked at her. "I'm not the expert on navigation. You'd better ask her."
"No!" cried Marlowe.
"Why not? Just because I'm a woman?" Her eyes were bright.
"But who taught you navigation?"