The Last Theorem - Arthur Charles Clarke [132]
And then she would pull out a few square meters of sail material and toss it toward her audience. The silvery film would coil and twist like smoke, and then drift toward the ceiling on the rising plume of warm air the human bodies made. And Natasha would continue:
“You can see how light the sail is. The whole square kilometer my yacht will deploy weighs less than a ton. That’s all we need. It’s enough to collect two kilograms of radiation pressure, so the sail will start to move…and the rigging will pull my Diana right along with it. Of course, the acceleration will be tiny—less than a thousandth of a G—but let’s see what that pitiful little thrust can do.
“In the first second, Diana will move about half a centimeter. Not even that much, really, because the rigging will stretch enough so that that first move can’t even be measured.”
She would turn toward the screen on the wall of the room, snapping her fingers to set it alight. It would display the vast, if almost impalpable, semi-cylindrical span of the sail, then zoom down to the passenger capsule—not much bigger than a motel shower stall—that would be Natasha’s home for the weeks in transit.
She would then go on. “After a minute, though, the motion is quite detectable. By then we’ve covered twenty meters, and our velocity has become nearly one kilometer per hour…with only a few hundred thousand more kilometers to go to reach the orbit of the moon.”
Then there would often be a faint titter from the audience. Natasha would smile back good-naturedly until it had died away, before going on. “That’s not bad, you know. After the first hour we’ll be sixty kilometers from our starting point, and by then we’ll be moving at a hundred kilometers an hour. And please remember where we are! All of this will be taking place in space, where there is no friction. Once you start something to move, it will move forever, with nothing slowing it down but the gravity of distant objects. You’ll be surprised when I tell you what kind of velocity our thousandth-of-a-G sailboat will be giving us by the end of its first day’s run. Almost three thousand kilometers an hour, all from the thrust of a sunlight pressure that you can’t even feel!”
Well, she’d convinced them. In the end the whole world had been convinced, or at least the people in high places, the decision makers, had been. Foundations, individuals, the treasuries of three great nations (and smaller amounts from dozens of smaller treasuries) had come together to meet the staggering bills for this event. It was paying off, though. The free-flying race in that old lunar lava tube had successfully sparked a trickle of actual lunar tourism. Now this new event already owned the biggest audience in history. And the big boys were already commissioning their prospector vessels, many of them solar-sail-driven themselves, to begin to investigate the raw material wealth of the solar system.
And here was young Natasha de Soyza Subramanian, right in the middle of it all!
Diana had made a good start. Now Natasha had time to take a look at the opposition. For starters she shrugged out of most of her clothing, since there was no one else around to see. Then, moving very cautiously—there were shock absorbers between her control capsule and the delicate rigging of the sail, but Natasha was determined to take no risks at all—she stationed herself at the periscope.
There the other spacecraft were, looking like strange silvery flowers planted in the dark fields of space. There was South America’s Santa Maria, Ron Olsos at the helm, only eighty kilometers