"Convulsions. A battle royal between a glandular-level panic and a violent and useless effort of the will to control the situation. Muscles tear, working against one another. Lungs rupture and air is forced into the blood-stream, causing embolism and death. Not everything is known about it, but I would guess that pregnant women are especially susceptible because their protective reflexes, through and through, are much more easily stimulated." "And the only thing that can be done about it is to supply gravity?" "Or centrifugal force (or centripetal, depending on where you're standing, but why be technical?)--or, better yet, keep those people off the ships." "So now Jack will spin the ship until I'm pressed against the walls with the same force as gravity, and then everything will be all right." "You make it sound so simple." "There's no need to be sarcastic!" Marcia blurted. "Jack can do it. You think he can, don't you? Don't you?" "He can do anything any space skipper has ever done, and more," said Sue Eagen, and her face glowed. "But it isn't easy. Right this minute he's working over the computer--a small, simple, ship-board computer--working out orbital and positional and blast-intensity data that would be a hard nut for the giant calculators on Earth to crack. And he's doing it in half the time--or less--than it would take the average mathematician, because he has to; because it's a life-and-death matter if he makes a mistake or takes too long." * * * * * "But--but--" "But what?" Miss Eagen's composure seemed to have been blasted to shreds by the powerful currents of her indignation. Her eyes flashed. "You mean, but why doesn't he just work the ship while it's spinning the same way he does when it isn't?" Through a growing fear, Marcia nodded mutely. "He'll spin the ship on its long axis," said the stewardess with exaggerated patience. "That means that the steering jet tubes in the nose and tail are spinning, too. You don't just turn with a blast on one tube or another. The blasts have to be let off in hundreds of short bursts, timed to the hundredth of a second, to be able to make even a slight course correction. The sighting instruments are wheeling round and round while you're checking your position. Your fuel has to be calculated to the last ounce--because enough fuel for a Moon flight, with hours of fuelless free-fall, and enough fuel for a power spin and course corrections while spinning, are two very different things. Captain McHenry won't be able to maneuver to a landing on the Moon. He'll do it exactly right the first time, or not at all." Marcia was white and still. "I--I never--"