Except for the baby none of them had any reason to expect more than minor and temporary discomfort from the change from planet-surface weight to the endless falling of free orbit. Their stomachs and the semicircular canals of their ears had been through the ordeal before; they were inured to it, salted.
Lowell was not used to it; his physical being rebelled against it, nor was he old enough to meet it calmly and without fear. He cried and made himself worse, alternating that with gagging and choking. Hazel and Meade took turns trying to quiet him. Meade finished her skimpy dinner and relieved the watch; when Hazel came into the control room where they were eating Roger Stone said, ‘How is he now?’
Hazel shrugged. ‘I tried to get him to play chess with me. He spat in my face.’
‘He must be getting better.’
‘Not so you could notice it.’
Castor said, ‘Gee whiz, Mother, can’t you dope him up till he gets his balance?’
‘No,’ answered Dr Stone, ‘I’m giving him the highest dosage now that his body mass will tolerate.’
‘How long do you think it will take him to snap out of it?’ asked her husband.
‘I can’t make a prediction. Ordinarily children adapt more readily than adults, as you know, dear — but we know also that some people never do adapt. They simply are constitutionally unable to go out into space.’
Pollux let his jaw sag. ‘You mean Buster is a natural-born groundhog?’ He made the word sound like both a crippling disability and a disgrace.
‘Pipe down,’ his father said sharply.
‘I mean nothing of the sort,’ his mother said crisply. ‘Lowell is having a bad time but he may adjust very soon.’
There was glum silence for some minutes. Pollux refilled his soup bag, got himself some crackers, and eased back to his perch with one leg hooked around a stanchion. He glanced at Castor; the two engaged in a conversation that consisted entirely of facial expressions and shrugs. Their father looked at them and looked away; the twins often talked to each other that way; the code — if it was a code — could not be read by anyone else. He turned to his wife. ‘Edith, do you honestly think there is a chance that Lowell may not adjust?’
‘A chance, of course.’ She did not elaborate, nor did she need to. Spacesickness like seasickness does not itself kill, but starvation and exhaustion do.
Castor whistled. ‘A fine time to find it out, after it’s too late. We’re already in orbit for Mars.’
Hazel said sharply. ‘You know better than that, Castor.’
‘Huh?’
‘Of course, dopy,’ his twin answered. ‘We’ll have to tack back.’ :1
‘Oh.’ Castor frowned. ‘I forgot for the moment that this was a two-legged jump.’ He sighed. ‘Well, that’s that. I guess we go back.’ There was one point and one only at which they could decide to return to the Moon. They were falling now toward Earth in a conventional ‘S-orbit” practically a straight line. They would pass very close to Earth in an hyperboloid at better than five miles per second, Earth relative. To continue to Mars they planned to increase this speed by firing the jet at the point of closest approach, falling thereby into an ellipsoid, relative to the Sun, which would let them fall to a rendezvous with Mars. They could reverse this maneuver, check their plunging progress by firing the jet against their motion and thereby force the Stone into an ellipsoid relative to Earth, a curve which, if correctly calculated, would take them back to Luna, back home before their baby brother could starve or wear himself out with retching. ‘Yep, that’s that,’ agreed Pollux. He suddenly grinned. ‘Anybody want to buy a load of bicycles? Cheap?’
‘Don’t be in too big a hurry to liquidate,’ his father told him, ‘but we appreciate your attitude. Edith, what do you think?’
‘I say we mustn’t take any chances,’ announced Hazel. ‘That baby is sick.’
Dr Stone hesitated: ‘Roger, how long is it to perigee?’
He glanced at his control board. ‘About thirty-five hours.’
‘Why don’t you prepare both maneuvers? Then we will not have to decide until it’s time to turn ship.’