He covered his face with his hands. ‘What do I do, Mother?’
‘You are captain, son.’
He sighed. ‘I suppose I knew it all along.’
‘Yes, but you had to struggle with it first.’ She kissed him. ‘Orders, son?’
‘Let’s get to it. It’s a good thing we didn’t waste any margin in departure.’
‘That it is.’
When Hazel told the others the news Castor asked, ‘Does Dad want us to compute a ballistic?’
‘No.’
‘A good thing — for we’ve got to get those bikes inboard, fast! Come on, Pol. Meade, how about suiting up and giving us a hand? Unless Mother needs you?’
‘She does,’ answered Hazel, ‘to take care of Lowell and keep him out of the way. But you won’t be bringing the bikes inboard.’
‘What? You can’t balance the ship for maneuvers with them where they are. Besides, the first blast would probably snap the wires and change your mass factor.’
‘Cas, where are your brains? Can’t you see the situation? We jettison.’
‘Huh? We throw away our bikes? After dragging almost to Mars?’
‘Your bikes, all our books, and everything else we can do without. The rough run-through on the computer made that clear as quartz; it’s the only way we can do this maneuver and still be sure of having a safe margin for homing in. Your father is checking over the weight schedule right now.’
‘But —,’ Castor’s face suddenly relaxed and became impassive. ‘Aye aye, ma’am.’
The twins were suiting up but had not yet gone outside when Pollux was struck by a notion. ‘Cas? We cut the bikes loose; then what happens?’
‘We charge it off to experience — and try to recover from Four-Planets Transit. They won’t pay up, of course.’
‘Use your skull. Where do the bikes end up?’
‘Huh? Why, at Mars!’
‘Right. Or pretty near. In the orbit we’re in now, they swing in mighty close and then head down Sunside again. Suppose, on closest approach, we are standing there waiting to snag ’em?’
‘Not a chance. It will take us just as long to get to Mars — and in a different orbit, same as the War God’s?
‘Yes, but just supposing. You know, I wish I had a spare radar beacon to hang on them. Then if we could reach them, we’d know where they were.’
‘Well, we haven’t got one. Say! Where did you put that used reflecting foil?’
‘Huh? Oh, I see. Grandpa, sometimes your senile decay is not quite so noticeable.’ The Stone had started out, of course, covered on one side of her living quarters by mirror-bright aluminium foil. As she drifted farther and farther from the Sun, reflecting the Sun’s heat had grown less necessary, absorbing it more desirable. To reduce the load on the ship’s heating and cooling system, square yards of it were peeled up and taken inside to store from week to week.
‘Let’s ask Dad.’
Hazel stopped them at the hatch to the control room. ‘He’s at the computer. What’s the complaint?’
‘Hazel, the reflecting foil we’ve been salvaging — is it on the jettison list?’
‘Certainly. We’ll pick up some more on Mars for the trip back. Why?’
‘A radar corner — that’s why!’ They explained the plan.
She nodded. ‘A long chance, but it makes sense. See here, wire everything we jettison to the bikes. We might get it all back.’
‘Sure thing!’ The twins got busy. While Pollux gathered together the bunches of bicycles, all but a few in good repair and brave with new paint, Castor constructed a curious geometrical toy. With 8-gauge wire, aluminium foil, and sticky tape he made a giant square of foil, edged and held flat with wire. This he bisected at right angles with a second square. The two squares he again bisected at the remaining possible right angle with a third square. The result was eight shiny right-angled corners facing among them in all possible directions — a radar reflector. Each corner would bounce radar waves directly back to source, a principle easily illustrated with a rubber ball and any room or box corner. The final result was to step up the effectiveness or radar from an inverse fourth-power law to an inverse square law — in theory, at least. In practice it would be somewhat less than perfectly efficient but the radar response of the assembly would be increased enormously. A mass so tagged would stand out on a radar screen like a candle in a cave.