To get the proper velocity, so you don't get smeared over your target planet, they used linear accelerators with a Hassan-Smith transmitter at one end and a receiver at the other. Civilians and other delicate things restricted most accelerators to a little more than one G. There were bulk cargo and military accelerators that boosted at twenty Gs, and sometimes more, but we weren't using those routes.
Accelerators boosted you for the length of the thing, and then transmitted you back to the beginning, to be boosted some more. You repeated the process until the proper speed was reached.
Of course, you not only needed the right speed, you needed it in the right direction. The linear accelerators had to be built inside a big sphere so they could be pointed in any direction, and because of the speeds involved, the accelerator had to be evacuated.
Getting a hard vacuum was fairly easy, since all you had to do was defocus the transmitter and turn it on. The air all went someplace, and on most planets you didn't much care where. We used the same trick to evacuate our Loway system.
On New Kashubia, which had to import all of its air, they just drained the accelerator into a mining shaft that went a few hundred kilometers down, letting gravity provide the vacuum, and then recovered the air from down there. I invented that trick myself, before I was forced to enlist in the army.
Finally, when you had the right speed and direction, the transmitter sent you not to the beginning of the accelerator again, but to the planet of your choice, provided they had a receiver waiting for you.
The key to successful transporter operation was that the transmitter had to know precisely where the receiver was at the instant of transmission, and precisely what its velocity vector was at that time. Being off by a few hundred meters, or by a few kilometers per hour, over interstellar distances, resulted in a disaster.
If the receiver wasn't where the transmitter thought it was, or if it wasn't operating, you just didn't arrive. Your constituent atoms were spread over a large volume of space, and that was the end of you. Because of this, receivers were built with a lot of backups, redundant circuits, and extra power supplies.
If the traffic wasn't too heavy, a planet could get along with only one transmitter, but they needed a receiver dedicated to each transmitter that they did business with, since they could never tell just when something was going to come in. Having two things come in at once to the same receiver resulted in losing not only both canisters, filled with whatever or whoever they were, but also the receiver and several surrounding city blocks.
Surprisingly, the system had a fairly decent safety record. Way better than that of ground cars or aircraft, anyway.
The original system had been started by Earth over two hundred years ago, long before the muon-exchange fusion power supply was perfected. Ice was mined on one of Neptune's moons and transmitted to a huge station circling the Sun inside the orbit of Mercury, where a solar-powered factory converted it to frozen balls of oxygen and hydrogen. From there it was sent out to fuel a growing fleet of computer-controlled space ships.
Since they didn't have to carry their fuel with them, these ships could use simple rocket technology to reach relativistic speeds, typically nine-tenths of the speed of light. Each ship contained an assembly area where it could put together transmitted modules that could form additional ships which would continue outward in a slightly different direction. The original twelve ships had grown to many thousands over the centuries.
The ships also received robot probe ships, which were released when the ship passed close to a star. These probes were accelerated not to the speed of the ship, but to the speed of the target star, so they parted company from their receiver quickly.
Fueled from Earth's solar system, the probes explored the new solar system, and put themselves into a convenient orbit there. Since we would probably never send another ship near that star again, even the most unpromising solar systems were sent a probe.
It was a matter of now or never.
Eventually, many habitable planets were found and colonized. Each planet was connected by Hassan-Smith transporters in the original probe back to Earth, which was the way Earth liked it.
The whole program of interstellar exploration and colonization had been monstrously expensive, and Earth wanted to make a profit off it. They charged excessively high rates for use of their transporters. They passed laws that all goods had to be shipped through the Earth's solar system, and the building of additional transporters between the colonies was forbidden. They starved their colonies, often quite literally, while getting richer and richer themselves. England had done similar things to its American colonies, before the revolution.
Some people never learn.
Naturally, the colonies objected to this, and starting from the manufacturing world of New Kashubia, receivers were smuggled in bits and pieces first to New Yugoslavia, and then to many of the other planets in Human Space. Once a planet had a receiver, a transmitter could be sent to them in pieces which, once assembled, let the planet join the smuggling network.
The colonies thrived.
All of the planets in the net thus had a connection to New Kashubia, where the transmitters and receivers were originally built. Since our rates were a tenth of what Earth charged, New Kashubia became the new hub of Human Space.
Earth, of course, was not informed of this development. They were led to believe that a recession was the cause of reduced shipments through its transporter network.
But you can't keep that big a thing a secret forever, and Earth was getting unhappy. The current war was a symptom of this.
The four standard days we spent in transit meant that we had four months in Dream World to get ready for the battle, which was fine by me. We had to prepare for a whole different style of fighting than we had been trained for, and a whole new set of weapons.
The humanoid drones we had been issued were particularly interesting. Even though I owned more of them than everybody else in Human Space combined, I'd never studied up on them. We had been using them only in the machine-controlled mode, for example, with the computer of a tank operating them.
There was also a human-controlled mode, where the tank's observer essentially "wore" the drone. The operator was in Dream World, but seeing through the drone's eyes, hearing through its ears, and feeling through its body. Once you got used to it, it was just like being there, except that the drone could be destroyed without getting you killed along with it.
Humanoid drones were twelve times stronger than a man. They could run faster, hit harder, and jump much higher. Jumping was augmented by explosive charges in the feet, which let you, once, get to the top of a five-story building in a single bound! There were impellers in the lower legs that could propel you through water at considerable speed, and lasers in each forearm that could be modulated for long-distance communications, or which, at full power, made very good antipersonnel weapons.
And they were fun! They made you feel so much like a comic book superhero that you wanted to go out and buy a cape!
Another interesting drone was the mouse. This was a spy device. About the size of its namesake, it ran silently on six articulated wheels, and gave you a set of eyes and ears where you could otherwise not go, either because you were too big, or because you were in danger of being shot. It also had tough, sharp little carbide teeth, that, given time, could nibble throught just about anything.
Other drones were mobile listening posts, mobile bombs, mobile gun platforms, or all three. They could release any of the various gas grenades we had with us, and do other impolite things.
All of our drones were equipped with Squid Skin coverings, as were our entire tanks, something I'd never seen before.
Squid Skin was an active camouflage system. A mildly intelligent computer kept track of where your enemy was, figured out what he would be seeing if you weren't there, and then made you look like that.
It was a fabric that contained millions of tiny colored balloons that could be inflated by the computer in any combination it wished. If all of the blue ones were inflated, and none of the others, you looked blue.
Of course, this only worked from one perspective. If you had two enemies looking at you from two different angles, you were no longer well hidden from both. It only worked over the human visual spectrum, and wouldn't fool radar, or the sensors in a tank. And under the best of circumstances, a single enemy could make out your outline if he looked carefully. But despite all this, Squid Skin was something that you wanted very badly when you were being shot at.
And obviously, Squid Skin could make you look like anything you wanted to look like, within reason. It could look a lot like civilian clothes, or any uniform you could imagine.
It was expensive stuff, but we had automatic factories turning it out by the acre, so for us, cost wasn't very important.
Then there was the problem of tactics. I had been trained to fight battles in the open field, or more usually, under it, since in dirt and stone, our ultrasonic rigs could tunnel along in a hurry. They weren't much good to us now, because New Kashubia was a solid metal ball.
The planet had started out as a gas giant circling an oversized star. About a billion years ago, the star had gone supernova, and had eventually converted itself into a neutron star. The gas giant had largely evaporated, with the small central core reduced to a ball of boiling, mostly vaporized metal. This ball eventually cooled, and as it did, the metals with the highest melting points solidified on the surface first, and those with lower melting points solidified later. This was a lot like zone refining, but on a planetary scale. Oh, there was a good deal of natural alloying, with a lot of eutectic alloys present, alloys with particularly low melting points.
Nonetheless, for the most part, New Kashubia was a series of concentric metal shells, with a layer of tungsten at the surface, and a pool of mercury at the center.
Metals conduct heat better than the rocks that Earth is mostly covered with. The planet had cooled all the way through to around twenty degrees Celsius, a comfortable temperature, heated mostly by residual radioactivity in some layers, and a twice yearly dousing by the searchlight beams of radiation that came from the neutron star it circled.
People mostly lived in the gold layer, since gold is among the least poisonous of the metals. The gravity was lighter down there as well.
Fighting inside of a metal ball that was populated by my own people wasn't something that I was looking forward to. The standard tactics for tunnel fighting had us throwing grenades around every corner before we went to see if there was anybody there. How the hell could we do something like that when my own family might be around that corner?
There had to be a better way.
I had five very intelligent and superbly well-trained subordinates working for me. Was there ever a combat squad before in history in which every member had a Ph.D. in Military Science? And I had six very intelligent machines as well. When they are well enough trained and programmed, humans and computers complement each other very well. The humans can do things that the computers are not very good at, and
vice versa.
After a month of working at standard tactics, out of the books as it were, we were all dissatisfied. None of the stuff we were learning really fit our strange situation. We had to work out something better on our own. I told Quincy, Zuzanna, and Conan that they were the Invaders from Earth, and that the rest of us were The Kashubian Volunteers, and we fought it out in Dream World. A week later, we traded sides, and went at it again. I shuffled the teams, made it girls against boys, and tried it a third time.
In every scenario we ran, there were a godawful number of civilian casualties.
Oh, we were guessing about a large number of things. We didn't know how many men and machines Earth was using to invade us. Earth had a population as large as that of all of the other planets combined. What percentage of that population were they throwing at us?
We had no idea.
We didn't know what the level of their military technology was. New Kashubia had been Earth's arsenal before we had nationalized all of the factories. Had they built another one in the intervening five years? Did they have a back up in the first place?
We just didn't know.
The only thing definitely in our favor was the receiving station through which we were entering New Kashubia.
The New Nigerian Transporters, a transmitter and three receivers, had been funded by a single wealthy individual as an act of charity, but in fact hunter-gatherers have very little use for interstellar trade, and the receivers at both ends of all three lines were usually idle.
The maps of New Kashubia that we had been provided with showed the receiver to be in the copper layer, and over fifty kilometers from much of anything else on the planet. Our engineers had been willing to take the philanthropical twit's money, but knew very well that a bunch of primitive hunter-gatherers wouldn't be sending us very much. For good and sufficient reasons, they had put the New Nigerian receiver where it wouldn't get in the way.
It wasn't likely that the Earth forces would be guarding it very carefully.
The general had done that much for us, anyway.
Quincy was our best man at close-in fighting, be it with a tank, a drone, or bare knuckles, so he was the first one of us to land on New Kashubia. I followed two minutes later, which was as fast as the small, New Nigerian transmitter would allow. In Dream World, that seemed like an hour. At combat speed, it was almost twice that.
When I got there, the receiver was standing on the floor of one of the forty-meter-wide mining tunnels that the huge mining machines drilled. The copper was slightly tarnished, suggesting that this tunnel had been filled with air for a while.