"I know, Daddy," said Diane. She forced a wisp of a smile to her lips. She understood as well as I did what he was trying to tell us. The Old Man was--and is--one of the greatest skippers who ever blasted a rocket. But he's an old man in fact as well as title. Twice before our employers had threatened to remove his command, ground him, give his bridge to a younger officer. A man of action, the Skipper dared not look forward to the day when he had to bid farewell to space. To refuse this emergency command would be to risk everything. And so: "I understand, Daddy," said Diane Hanson "But you don't have to leave me." "And, Sparks, tell Todd he'll serve as First Mate," the skipper told me. "Wilson will be Second--_hey?_ What did you say, Diane?" Diane's voice was gentle, but there was a tightness about her eyes and lips I recognized. I'd seen it before, on her father's face. I knew what it meant. Stubbornness mixed with a dash of determination. "You won't leave me," she said calmly, "because I'm going with you!" "You're going with--Oh, no! No, you're not! This isn't any shuttle for a girl. There's danger out there near Jupiter, honey. I won't let you--" "You can't stop me, Dad. Can't you see I've _got_ to go? Please! I'll go crazy sitting home here by myself. And besides, it was out there--near Jupiter--that _he_--" Well, I saw how she felt. And I didn't much blame her for feeling she had a right to make at least one farewell trip to the part of space wherefrom her lover had disappeared. The Old Man growled softly. Then he wiped his glasses with a sort of savage vehemence. And he said, "Well, then, get your things packed. And Sparks--call Chief Garrity. Tell him to have the hypos and all control equipment ready for immediate flight--" Thus at twelve midnight sharp, Earth time, which is 7-R-4 Solar Constant, the _Saturn_ lifted gravs for Europa, the second satellite of monstrous Jupiter. * * * * * There's no use boring you with the routine details. We blasted from a Long Island cradle, set course and constant for Europa, waited till we were about six hours away from the Earth's gravitational field, then cut over to the V-I unit--the "velocity intensifier" invented by Lancelot Biggs which had made the _Saturn_ the fastest ship in space, increasing its speed potential from a slovenly 200,000 _mph_ to something only a trifle less than the limiting velocity of light. In the old days, before the installation of the V-I unit, a shuttle to Jupiter meant a journey of about a hundred days, more or less, depending on the positions of the planets. Now, however, the _Saturn_ had a speed potential of 650,000,000 miles per hour! Which _didn't_ mean that we could actually get to Jupiter in an hour. There were other factors which had to be allowed for: initial velocity, deceleration upon approaching our goal, and all that stuff.