Long nodded. ‘If you like.’
Rioz took a hesitant step forward. Space was clear, so to hell with sitting and looking at a blank, green, pipless line. He said, ‘What’s the Grounder been talking about?’
‘History of space travel mostly. Old stuff, but he’s doing it well. He’s giving the whole works – color cartoons, trick photography, stills from old films, everything.’
As if to illustrate Long’s remarks, the bearded figure faded out of view, and a cross-sectional view of a spaceship flitted onto the screen. Hilder’s voice continued, pointing out features of interest that appeared in schematic color. The communications system of the ship outlined itself in red as he talked about it, the storerooms, the patron micropile drive, the cybernetic circuits . . .
Then Hilder was back on the screen. ‘But this is only the travelhead of the ship. What moves it? What gets it off the Earth?’
Everyone knew what moved a spaceship, but Hilder’s voice was like a drug. He made spaceship propulsion sound like the secret of the ages, like an ultimate revelation. Even Rioz felt a slight tingling of suspense, though he had spent the greater part of his life aboard ship.
Hilder went on. ‘Scientists call it different names. They call it the Law of Action and Reaction. Sometimes they call it Newton’s Third Law. Sometimes they call it Conservation of Momentum. But we don’t have to call it any name. We can just use our common sense. When we swim we push water backward and move forward ourselves. When we walk, we push back against the ground and move forward. When we fly a gyroflivver, we push air backward and move forward.
‘Nothing can move forward unless something else moves backward. It’s the Old principle of ‘You can’t get something for nothing.’
Now 1magme a spaceship hat weighs a hundred thousand tons lifting off Earth. To do that, somethmg else must be moved downward. Since a spaceship is extremely heavy, a great deal of material must be moved downward_. So much aterial, in fact, that there is no place to keep it all aboard ship. A special compartment must be built behind the ship to hold it.’
Again Hilder faded out and the ship returned. It shrank and a trunated cone appeared behind it. In bright yellow, words appeared within 1t: MATERIAL TO BE THROWN AWAY.
‘But now,’ said Hilder, ‘the total weight of the ship is much greater. You need still more propulsion and still more.’
The ship shrank enormously to add on another larger shell and still another immense one. The ship proper, the travel-head, was a little dot on the screen, a glowing red dot.
Rioz said, ‘Hell, this is kindergarden stuff.’
‘Not to the people he’s speaking to, Mario,’ replied Long. ‘Earth isn’t M rs. There must be billions of Earth people who’ve never seen a spaceship; don’t know the first thing about it.’
Hilder was saying, ‘When the material inside the biggest shell is used up, the shell is detached. It’s thrown away, too.’
The outermost shell came loose, wobbled about the screen.
‘Then the second one goes,’ said Hilder, ‘and then, if the trip is a long one, the last is ejected.’
The ship was just a red dot now, with three shells shifting and moving, lost m space.
Hilder said, ‘These shells represent a hundred thousand tons of tungsten, magnesium, aluminum, and steel. They are gone forever from Earth. Mars is ringed by Scavengers, waiting along the routes of space travel, waitmg for the cast-off shells, netting and branding them, saving them for Mars. Not one cent of payment reaches Earth for them. They are salvage. They belong to the ship that finds them.’
Rioz said, ‘We risk our investment and our lives. If we don’t pick them up, no one gets them. What loss is that to Earth?’
‘Look,’ said Long, ‘he’s been talking about nothing but the drain that Mars, Venus, and the Moon put on Earth. This is just another item of loss.’
‘They’ll get their return. We’re mining more iron every year.’
‘And most of it goes right back into Mars. If you can believe his figures, Earth has invested .two hundred billion dollars in Mars and received back about five billion dollars’ worth of iron. It’s put five hundred billion dollars into the Moon and gotten back a little over twenty-five billion dollars of magnesium, titanium, and assorted light metals. It’s put fifty billion dollars into Venus and gotten back nothing. And that’s what the taxpayers of Earth are really interested in – tax money out; nothing in.’
The screen was filled, as he spoke, with diagrams of the Scavengers on the route to Mars; little, grinning caricatures of ships, reaching out wiry, tenuous arms that groped for the tumbling, empty shells, seizing and snaking them in, branding them MARS PROPERTY in glowing letters, then scaling them down to Phobos.
Then it was Hilder again. ‘They tell us eventually they will return it all to us. Eventually! Once they are a going concern! We don’t know when that will be. A century from now? A thousand years? A million? ‘Eventually.’ Let’s take them at their word. Someday they will give us back all our metals. Someday they will grow their own food, use their own power, live their own lives.
‘But one thing they can never return. Not in a hundred million years. Water!
‘Mars has only a trickle of water because it is too small. Venus has no water at all because it is too hot. The Moon has none because it is too hot and too small. So Earth must supply not only drinking water and washing water for the Spacers, water to run their industries, water for the hydroponic factories they claim to be setting up-but even water to throw away by the millions of tons.
‘What is the propulsive force that spaceships use? What is it they throw behind so that they can accelerate forward? Once it was the gases generated from explosives. That was very expensive. Then the proton micropile was invented – a cheap power source that could heat up any liquid until it was a gas under tremendous pressure. What is the cheapest and most plentiful liquid available? Why, water, of course.
‘Each spaceship leaves Earth carrying nearly a million tons – not pounds, tons – of water, for the sole purpose of driving it into space, so that it may speed up or slow down.
‘Our ancestors burned the oil of Earth madly and willfully. They destroyed its coal recklessly. We despise and condemn them for that, but at least they had this excuse – they thought that when the need arose, substitutes would be found. And they were right. We have our plankton farms and our proton micropiles.
‘But there is no substitute for water. None! There never can be. And when our descendants view the desert we will have made of Earth, what excuse will they find for us? When the droughts come and grow—’
Long leaned forward and turned off the set. He said, ‘That bothers me. The damn fool is deliberately – What’s the matter?’
Rioz had risen uneasily to his feet. ‘I ought to be watching the pips.’
‘The hell with the pips.’ Long got up likewise, followed Rioz through the narrow corridor, and stood just inside the pilot room. ‘If Hilder carries this through, if he’s got the guts to make a real issue out of it Wow!’
He had seen it too. The pip was a Class A, racing after the outgoing signal hke a greyhound after a mechanical rabbit.
Rioz was babbling, ‘Space was clear, I tell you, clear. For Mar’s sake, Ted, don’t just freeze on me. See if’you can spot it visually.’
Rioz was working speedily and with an efficiency that was the result of nearly twenty years of scavenging. He had the distance in two minutes. Then remembering Swenson’s experience, he measured the angle of declination and the radial velocity as well.
He yelled at Long, ‘One point seven six radians. You can’t miss it, man.’
Long held his breath as he adjusted the vernier. ‘It’s only half a radian off the sun. It’ll only be crescent-lit.’
He increased magnification as rapidly as he dared, watching for the one ‘star’ that changed p’osition and grew to have a form revealing itself to be no star.
