"Simple matter," said Pendray. "Nothing to it. Two equations. Little ship goes thirty times as fast as big ship--big _hulk_. Had to get here before 22 June. _Had_ to. Only way out, y'unnerstand. "Anyway. Two equations. Simple. Work 'em in your head. Big ship takes ten months, little one takes ten days. But can't stay in a little ship ten days. No shielding. Be dead before you got here. See?" "I see," said the captain patiently. "_But_--and here's a 'mportant point: If you stay on the big ship for eight an' a half months, then y' only got to be in the little ship for a day an' a half to get here. Man can live that long, even under that radiation. See?" And with that, he closed his eyes. "Do you mean you exposed yourself to the full leakage radiation from a lifeboat engine for thirty-six hours?" But there was no answer. "Let him sleep," said the ship's doctor. "If he wakes up again, I'll let you know. But he might not be very lucid from here on in." "Is there anything you can do?" the captain asked. "No. Not after a radiation dosage like that." He looked down at Pendray. "His problem was easy, mathematically. But not psychologically. That took real guts to solve." "Yeah," said the captain gently. "All he had to do was _get_ here alive. The problem said nothing about his staying that way."