* * * * *
I
"Beep!" said the radio smugly. "_Beep! Beep! Beep!_"
"There's one," said the man at the pickup controls of tugship 431. He
checked the numbers on the various dials of his instruments. Then he
carefully marked down in his log book the facts that the radio finder
was radiating its beep on such-and-such a frequency and that that
frequency and that rate-of-beep indicated that the asteroid had been
found and set with anchor by a Captain Jules St. Simon. The direction
and distance were duly noted.
That information on direction and distance had already been
transmitted to the instruments of the tugship's pilot. "Jazzy-o!" said
the pilot. "Got 'im."
He swiveled his ship around until the nose was in line with the beep
and then jammed down on the forward accelerator for a few seconds.
Then he took his foot off it and waited while the ship approached the
asteroid.
In the darkness of space, only points of light were visible. Off to
the left, the sun was a small, glaring spot of whiteness that couldn't
be looked at directly. Even out here in the Belt, between the orbits
of Mars and Jupiter, that massive stellar engine blasted out enough
energy to make it uncomfortable to look at with the naked eye. But it
could illuminate matter only; the hard vacuum of space remained dark.
The pilot could have located the planets easily, without looking
around. He knew where each and every one of them were. He had to.
A man can navigate in space by instrument, and he can take the time to
figure out where every planet ought to be. But if he does, he won't
really be able to navigate in the Asteroid Belt.
In the Nineteenth Century, Mark Twain pointed out that a steamboat
pilot who navigated a ship up and down the Mississippi had to be able
to identify every landmark and every changing sandbar along the river
before he would be allowed to take charge of the wheel. He not only
had to memorize the whole river, but be able to predict the changes in
its course and the variations in its eddies. He had to be able to know
exactly where he was at every moment, even in the blackest of moonless
nights, simply by glancing around him.
An asteroid man has to be able to do the same thing. The human mind is
capable of it, and one thing that the men and women of the Belt Cities
had learned was to use the human mind.
"Looks like a big 'un, Jack," said the instrument man. His eyes were
on the radar screen. It not only gave him a picture of the body of the
slowly spinning mountain, but the distance and the angular and radial
velocities. A duplicate of the instrument gave the same information to
the pilot.
The asteroid was fairly large as such planetary debris went--some five
hundred meters in diameter, with a mass of around one hundred
seventy-four million metric tons.
* * * * *
Within twenty meters of the surface of the great mountain of stone,
the pilot brought the ship to a dead stop in relation to that surface.
"Looks like she's got a nice spin on her," he said. "We'll see."
He waited for what he knew would appear somewhere near the equator of
the slowly revolving mass. It did. A silvery splash of paint that had
originally been squirted on by the anchor man who had first spotted
the asteroid in order to check the rotational velocity.
The pilot of the space tug waited until the blotch was centered in the
crosshairs of his peeper and then punched the timer. When it came
around again, he would be able to compute the angular momentum of the
gigantic rock.
"Where's he got his anchor set?" the pilot asked his instrument man.
"The beep's from the North Pole," the instrument man reported
instantly. "How's her spin?"
"Wait a bit. The spot hasn't come round again yet. Looks like we'll
have some fun with her, though." He kept three stars fixed carefully
in his spotters to make sure he didn't drift enough to throw his
calculations off. And waited.
Meanwhile, the instrument man abandoned his radar panel and turned to
the locker where his vacuum suit waited at the ready. By the time the
pilot had seen the splotch of silver come round again and timed it,
the instrument man was ready in his vacuum suit.
"Sixteen minutes, forty seconds," the pilot reported. "Angular
momentum one point one times ten to the twenty-first gram centimeters
squared per second."
"So we play Ride 'Em Cowboy," the instrument man said "I'm evacuating.
Tell me when." He had already poised his finger over the switch that
would pull the air from his compartments, which had been sealed off
from the pilot's compartment when the timing had started.
"Start the pump," said the pilot.
The switch was pressed, and the pumps began to evacuate the air from
the compartment. At the same time, the pilot jockeyed the ship to a
position over the north pole of the asteroid.
"Over" isn't quite the right word. "Next to" is not much better, but
at least it has no implied up-and-down orientation. The surface
gravity of the asteroid was only two millionths of a Standard Gee,
which is hardly enough to give any noticeable impression to the human
nervous system.
"Surface at two meters," said the pilot. "Holding."
* * * * *
The instrument man opened the outer door and saw the surface of the
gigantic rock a couple of yards in front of him. And projecting from
that surface was the eye of an eyebolt that had been firmly anchored
in the depths of the asteroid, a nickel-steel shaft thirty feet long
and eight inches in diameter, of which only the eye at the end showed.
The instrument man checked to make sure that his safety line was
firmly anchored and then pushed himself across the intervening space
to grasp the eye with a space-gloved hand.
This was the anchor.
Moving a nickel-iron asteroid across space to nearest processing plant
is a relatively simple job. You slap a powerful electromagnet on her,
pour on the juice, and off you go.
The stony asteroids are a different matter. You have to have something
to latch on to, and that's where the anchor-setter comes in. His job
is to put that anchor in there. That's the first space job a man can
get in the Belt, the only way to get space experience. Working by
himself, a man learns to preserve his own life out there.
Operating a space tug, on the other hand, is a two-man job because a
man cannot both be on the surface of the asteroid and in his ship at
the same time. But every space tug man has had long experience as an
anchor setter before he's allowed to be in a position where he is
capable of killing someone besides himself if he makes a stupid
mistake in that deadly vacuum.
"On contact, Jack," the instrument man said as soon as he had a firm
grip on the anchor. "Release safety line."
"Safety line released, Harry," Jack's voice said in his earphones.
Jack had pressed a switch that released the ship's end of the safety
line so that it now floated free. Harry pulled it towards himself and
attached the free end to the eye of the anchor bolt, on a loop of
nickel-steel that had been placed there for that purpose. "Safety line
secured," he reported. "Ready for tug line."
In the pilot's compartment, Jack manipulated the controls again. The
ship moved away from the asteroid and yawed around so that the "tail"
was pointed toward the anchor bolt. Protruding from a special port was
a heavy-duty universal joint with special attachments. Harry reached
out, grasped it with one hand, and pulled it toward him, guiding it
toward the eyebolt. A cable attached to its other end snaked out of
the tug.
Harry worked hard for some ten or fifteen minutes to get the universal
joint firmly bolted to the eye of the anchor. When he was through, he
said: "O.K., Jack. Try 'er."
The tug moved gently away from the asteroid, and the cable that bound
the two together became taut. Harry carefully inspected his handiwork
to make sure that everything had been done properly and that the
mechanism would stand the stress.
"So far so good," he muttered, more to himself than to Jack.
Then he carefully set two compact little strain gauges on the anchor
itself, at ninety degrees from each other on the circumference of the
huge anchor bolt. Two others were already in position in the universal
joint itself. When everything was ready, he said: "Give 'er a try at
length."
The tug moved away from the asteroid, paying out the cable as it
went.
Hauling around an asteroid that had a mass on the order of one hundred
seventy-four million metric tons required adequate preparation. The
nonmagnetic stony asteroids are an absolute necessity for the Belt
Cities. In order to live, man needs oxygen, and there is no trace of
an atmosphere on any of the little Belt worlds except that which Man
has made himself and sealed off to prevent it from escaping into
space. Carefully conserved though that oxygen is, no process is or can
be one hundred per cent efficient. There will be leakage into space,
and that which is lost must be replaced. To bring oxygen from Earth in
liquid form would be outrageously expensive and even more outrageously
inefficient--and no other planet in the System has free oxygen for the
taking. It is much easier to use Solar energy to take it out of its
compounds, and those compounds are much more readily available in
space, where it is not necessary to fight the gravitational pull of a
planet to get them. The stony asteroids average thirty-six per cent
oxygen by mass; the rest of it is silicon, magnesium, aluminum,
nickel, and calcium, with respectable traces of sodium, chromium,
phosphorous manganese, cobalt, potassium, and titanium. The metallic
nickel-iron asteroids made an excellent source of export products to
ship to Earth, but the stony asteroids were for home consumption.
This particular asteroid presented problems. Not highly unusual
problems, but problems nonetheless. It was massive and had a high rate
of spin. In addition, its axis of spin was at an angle of eighty-one
degrees to the direction in which the tug would have to tow it to get
it to the processing plant. The asteroid was, in effect, a huge
gyroscope, and it would take quite a bit of push to get that axis
tilted in the direction that Harry Morgan and Jack Latrobe wanted it
to go. In theory, they could just have latched on, pulled, and let the
thing precess in any way it wanted to. The trouble is that that would
not have been too good for the anchor bolt. A steady pull on the
anchor bolt was one thing: a nickel-steel bolt like that could take a
pull of close to twelve million pounds as long as that pull was along
the axis. Flexing it--which would happen if they let the asteroid
precess at will--would soon fatigue even that heavy bolt.
The cable they didn't have to worry about. Each strand was a fine wire
of two-phase material--the harder phase being borazon, the softer
being tungsten carbide. Winding these fine wires into a cable made a
flexible rope that was essentially a three-phase material--with the
vacuum of space acting as the third phase. With a tensile strength
above a hundred million pounds per square inch, a half inch cable
could easily apply more pressure to that anchor than it could take.
There was a need for that strong cable: a snapping cable that is
suddenly released from a tension of many millions of pounds can be
dangerous in the extreme, forming a writhing whip that can lash
through a spacesuit as though it did not exist. What damage it did to
flesh and bone after that was of minor importance; a man who loses all
his air in explosive decompression certainly has very little use for
flesh and bone thereafter.
"All O.K. here," Jack's voice came over Harry's headphones.
"And here," Harry said. The strain gauges showed nothing out of the
ordinary.
"O.K. Let's see if we can flip this monster over," Harry said,
satisfied that the equipment would take the stress that would be
applied to it.
He did not suspect the kind of stress that would be applied to him
within a few short months.