ORICHLACUM UNIVERSE sidebar: Interstellar Communications in 2123...

[Johnny1A.2]

ORICHLACUM UNIVERSE sidebar: Interstellar Communications in 2123...

In 2123, faster-than-light interstellar travel is established, and faster-than-light signaling is also a thing. Transceivers exist that can communicate enormously faster than any starship can travel, but the only usual way to communicate between star systems faster than light is to send a starship.

The reason is range limits. Even the largest FTL transmitters in the Solar System simply do not have the range to reach even the nearest stars, except under the most freakish of circumstances.

Faster than light signals exist in multiple levels, or 'orders', and propagate at a rate of (x^x)c, where 'x' is the order. That is, second order signals propage at 2^2 times c, or 4 times the velocity of light. A third order signal propagates at 3^3c, or 27 times the speed of light, and so on. While the lower-order signals are slower than most starships, fourth order and higher signals are faster than the vast majority of ships.

In 2123, transmission facilities exist in the Solar System that can transmit eighth order signals. These signals propagate at 16,777,216c. This would be fast enough to send a message from Sol to Alpha Centauri in slightly over eight seconds, or to send a message to the far rim of the Milky Way in under two Terran days.

Unfortunately, the practical range of these huge transmitter complexes is usually about one light-year. This varies up and down with cosmic conditions, and under extremely rare, freakish galactic conditions, transmissions have been successfully made between Sol and nearby stars. These conditions are always brief, rarely predictable, and might happen perhaps once in two or three years and last no more than hours. The one light year bound is a typical limit, though when conditions are particularly bad it might drop to half or a quarter of that.

(In practice it also depends on the size and sensitivity of the receiving station as well, of course.)

For reasons of physics, high-order FTL communications and sensory systems need to be well clear of planetary surfaces to work. Second and third order FTL transceivers can work on the surface of the Earth, and they are used for most in-System FTL communications. Higher-order systems are constructed in Earth orbit, or sometimes in Solar orbit, depending on the precise purpose of the installation.

Such stations require orichalcum, and that, together with the intricate and expensive technology necessary for translight communications and sensing, makes these facilities immensely expensive. They are also physically large, because they require large power supplies and extensive heat dissipation systems.

This is one of the reasons for the short range of such communications systems. In 2123, the process of generating FTL signals is tremendously inefficient, especially for the higher-order, faster signals. A typical eighth order transmitter might have a power input of ten gigawatts, and of that immense power it might emit perhaps one megawatt of eighth level signal.

Lower order signals can be generated somewhat more efficiently, but the ratio is still ruinous.

Of course, if one megawatt emerges as signal, the remaining nine million and nine hundred ninety-nine thousand kilowatts do not just disappear, they emerge as heat, and that heat has to be removed if the transmitter (to say nothing of the rest of the facility around it) is not to melt or vaporize. In practice, this means that enormous heat radiators are necessary.

Adding to the size of these facilities is the fact that with such low power output, broadcast signals are impractical, such communications require tight-beam transmission to be useful at all, which further requires very precise targeting to avoid missing the receiving station, which means large 'antennae' on the transmitter.

To be continued...

[Johnny1A.2]

ORICHLACUM UNIVERSE sidebar: Interstellar Communications in 2123 continued...

In 2123, most of the major nations and powers have at least one orbiting sensor/communications platform in geostationary orbit. Geostationary orbit is preferred because it is high enough/far enough out to permit the machinery to work efficiently, and the equatorial orbit permits these stations to 'hold position' relative to the surface of the Earth. Holding position in this way enables the station to remain above the home territory of its parent state, and it simplifies tight-beam and laser communications with ground stations, making it simpler to maintain information security.

The communications transmitters on these stations can maintain sixth, seventh or eighth-order communications with equivalent transceivers, on average, out to about one light-year. That is an average, as noted above, galactic conditions can cause that distance to vary widely over time. Still, the average of one light-year is fairly reliable.

In practice, most starships carry far less capable communications facilities, meaning that they can readily receive the high-order communications from the Earth-orbital stations further out than they can reply. The high sensitivity of the receivers on the orbital stations enables them to pull in messages from the relatively small transmitters aboard starships at a substantial distance, but much less than their effective transmission range.

Depending on the facilities aboard a ship, the orbital platforms can usually pick up a message at about one fourth the distance that they can send a message to that same ship. Also, because lower-order signals are easier to generate and require less massive and delicate and expensive apparatus, most starship transmitters are limited to fourth order signals. These signals propagate far more slowly than the sixth, seventh, and eighth level signals the communications stations usually transmit.

Eighth-order signals are by far the most expensive in terms of energy and delicate control, and so even though they are the fastest available, they are reserved for the highest priority needs. Given the modest ranges possible, sixth and seventh-order signals are usually more than swift enough for most purposes.

For example, a starship at the usual limit of reception range, about a light-year out, would receive an eighth-order signal from Earth orbit with a time lag of about 1.8 seconds. At that same distance a seventh-order signal would arrive after about 38 seconds. A sixth-order signal would require slightly more than eleven minutes. Obviously, for most purposes sixth-order signals are fully sufficient and far cheaper in terms of energy and effort.

To answer back, a starship would usually need to be no further out than about three light-months, and would usually be limited to fourth-order signals. A fourth-order transmission from that distance would need almost nine hours to arrive at the stations in GEO. If expense or other factors limit a ship to third-order transmissions, which is by no means unusual, that same distance would require three days and a bit over nine hours to arrive at Earth.

Given the fantastic expense, and limited utility, of the higher-order signal systems under these circumstances, it would not necessarily be cost effective to build the enormous orbital platforms for communications alone. They are constructed anyway, though, because they also serve another purpose.

The other function these platforms serve is sensory. Aboard these orbital stations are the (mostly) passive and (very limited) active FTL sensing systems the major powers use to watch the skies. The active sensing range is substantially less than the transmission range (because reflected signals are so faint), but this is still sufficient to provide a certain amount of useful information about the space around Sol.

There are also passive FTL observation systems on these platforms, analogous to telescopes. These have, as with any passive sensor, theoretically infinite range, but in practice they are usually useful out to about one light-year before the various forms of interference reduce the signal-to-noise ratio below utility. As with the communications systems, galactic conditions affect the passive sensor range, sometimes increasing it, more often reducing it, but again, one light year is about the average.

Geostationary orbit is good enough for most applications of this technology, but the Sun blocks observation in certain directions at any given time. For that reason, some of the major powers have built such stations in orbit around both Mars and Venus. Most of the time, the planets are spread out around the Sun, giving full coverage of the sky in all directions around Sol. Still, occasionally, Venus, Earth, and Mars all line up, and because of that, both the Empire and the United States also maintain observation platforms in solar orbit at the Terran Trojan positions. From these positions, it is usually possible to 'see past' the Sun.

(The Empire maintains a station at the leading Terran Trojan, America has one at the trailing Terran Trojan, and the Chinese have one under construction in the trailing Terran Trojan as well.)

Altogether, in 2123, the Empire maintains six such stations, three in Earth GEO, one in the leading Terran Trojan, and one each orbiting Venus and Mars. The USA maintains four, two in Earth orbit, one orbiting Mars, and the one in the trailing Terran Trojan. The Chinese have one in Earth orbit, one in Venus orbit, and one under construction in the trailing Terran Trojan. Australia maintains two, one in Terran GEO and one orbiting Mars, Argentina has one in Terran GEO, as does the Islamic Sultanate.

To be continued...

[Johnny1A.2]

ORICHLACUM UNIVERSE sidebar: Interstellar Communications in 2123 continued...

These various orbital stations are of various designs, of course, but all of them have certain things in common. They are all physically large, including enormous heat dissipation systems. They are all manned, and all heavily armed and shielded, because of the enormous strategic importance of the facilities, and the exceedingly expensive orichalcum (and to a lesser degree other things) the facilities incorporate.

All of these stations have tightly-secured volumes within which entry is prohibited. Typically, each such station has an outer defense volume and an inner sphere. Ships entering the outer sphere receive one warning and are fired upon, anything entering the inner sphere without authorization is fired upon immediately.

Furthermore, the various traffic-control centers that monitor space traffic in the Solar System route traffic well away from the defense zones around these stations, and any ship on an orbital trajectory or trans-light approach line that is projected to intersect such a zone is immediately rerouted.

All of these stations are maintained by governments. Access to the communications facilities is sometimes made available to private groups, usually for a fee, but this varies from state to state and time to time, and of course governmental traffic always has priority over private messages.

Some large corporate and business groups have contemplated constructing their own FTL communications stations. The fantastic expense of such, even allowing for lower cost because of the lack of need for the sophisticated sensor systems, has so far made it no more than a speculative project, though some large corporations have engaged in quiet talks about the idea of creating a consortium to create a shared facility.

This would be a complex project. Along with the sheer cost, there would be issues of getting permission to construct such a facility, such permission would by no means by a sure thing in 2123. At least as of 2123, the talk remains no more than talk.

[Prince Charon]

I feel like I've missed or forgotten something important: Who are 'the Empire,' please?

[Johnny1A.2]

Originally Posted by Prince Charon

I feel like I've missed or forgotten something important: Who are 'the Empire,' please?

That's because I've never gotten around to detailing the international setting a century from now. I keep meaning to, and I keep getting side-tracked.

Super-short version: in 2123, the Empire is the largest single government on Earth, it rules over half the planet and parts of the rest of the Solar System, and over half the population thereof, and it claims to have de jure rule over all of it. These claims are disputed, vigorously, by various states.

The Empire is highly heterogeneous, is very complex, and it is the most powerful single state (though it is so complex that it often acts more like a vast federal structure). Its primary geopolitical rivals are the USA, Argentina, and Australia (often shorted to the 3A or the Triple-A (the American Automotive Assocation is long gone) a century from now, because they are a close alliance that usually acts in opposition to the Empire), as well as Neochina (a sort of republic in 2123) and the Islamic Sultanate (very complicated). There are other independent powers, but they are minor players.

That's the super-condensed way-oversimplified version.

I really need to get around to that 22nd Century travel guide...