Category: [TECHNOLOGY]
Type: [Starship Communications System, Regulated Equipment]
Canon Tier: Tier 2 (Expanded Universe; pending Council review)
Tags: [NEW-TECH] [NEW-INSTITUTION] [PLOT-DEVICE]
The comms array is the radio and laser head that connects a ship to the rest of human space. It is a folding 1.0 m dish, a pair of whip antennas, a transceiver and a transponder, packaged into a 0.2 t radial module that draws 2 kW. Under the grey line a ship’s array moves at most about 10 Mb s⁻¹, a thousandth of the 10 Gb s⁻¹ legal ceiling of public networks, so it carries chat, voice, messages and mission traffic but never bulk data. Light-lag does the rest: a reply from 10 AU away takes more than two hours. The transponder is a legal requirement everywhere that matters, because a ship that cannot be heard cannot be cleared into a berth, and a ship that will not be heard is assumed hostile.
| Symbol/Parameter | Meaning/Description | Value / Specification |
|---|---|---|
| Module | Mass, stowed envelope | 0.2 t; 1.2 × 1.4 × 1.2 m |
| Power | Draw at nominal (transmit and receive), also the heat load | 2 kW |
| Rated range | Out to which a station terminal still receives ≥ 100 kb s⁻¹ | $1.5 \times 10^{12}$ m (10.0 AU) |
| Channel rate | Per-channel maximum | $10^7$ b s⁻¹ (10 Mb s⁻¹) |
| Services | Gated by the array | Chat, voice, messages, transmissions, traffic control |
| Components | Dish, whip antennas, transceiver, transponder | |
| Band | Ka band | 32 GHz ($\lambda = 9.4$ mm) |
| Dish | 1.0 m, aperture efficiency 0.6 | gain 48 dBi ($G \approx 6.7 \times 10^4$) |
| RF power | Transmitted (≈ 25% of the 2 kW draw) | 500 W; EIRP $3.4 \times 10^7$ W |
| Receiver noise | System temperature | 30 K |
Link rate. The received power is $P_r = P_t G_t G_r (\lambda / 4 \pi d)^2$, the capacity is $P_r / (k T \ln 2)$ and the practical rate is one tenth of that (coding, pointing and margin), capped at the 10 Mb s⁻¹ channel limit:
| Link | 1 AU | 5.2 AU (Jupiter) | 10 AU | Full 10 Mb s⁻¹ out to |
|---|---|---|---|---|
| Ship to ship (1 m dish at both ends) | 20 kb s⁻¹ | 0.7 kb s⁻¹ | 0.2 kb s⁻¹ | $6.7 \times 10^9$ m (0.045 AU) |
| Ship to station (25 m dish) | 10 Mb s⁻¹ (capped) | 460 kb s⁻¹ | 120 kb s⁻¹ | 1.1 AU |
Light-lag (one way, $d / c$):
| Distance | Example | Delay |
|---|---|---|
| $3.84 \times 10^8$ m | Earth to Moon | 1.3 s |
| 1 AU | Earth to Sun | 8.3 min |
| 2.7 AU | Main Belt | 22 min |
| 5.2 AU | Jupiter | 43 min |
| 10 AU | Rated range | 83 min |
Bandwidth tiers under the grey line.
| Tier | Typical hardware | Rate per channel | Notes |
|---|---|---|---|
| 0: lamp | Station signal lamp, ship nav lights | ≈ 10 b s⁻¹ | No power or array needed beyond the lamp |
| 1: ship array | The module above | 10 Mb s⁻¹ | Sub-Grey-Line flight computer |
| 2: port relay | Port and station dishes | ≈ 1 Gb s⁻¹ | Several channels, each isolated |
| 3: public trunk | Planetary and inter-station fibre | ≤ 10 Gb s⁻¹ | The legal per-channel cap (grey line); open systems stay under the 20 Gb s⁻¹ wildcode threshold |
Moving a data volume $V$ at rate $R$ takes $V / R$: 1 GB over a ship array is 13 min; 1 TB is 9.3 days; 1 PB is 25 years. The same petabyte on a public trunk at the grey line is 9.3 days, and in a courier’s hold it is as long as the trip.
The array is the ship’s only voice: the chat and voice services are what a crew uses to talk to a port and to each other across a battlefield, messages are store-and-forward mail, and transmissions are everything in between, from mission updates to a remote contract being accepted or completed. traffic_control is the fifth service: clearance, lane assignment, torch interlock and auto-dock (see below). A ship carries one array as standard; a second, on a different bearing, is a common mark of a tramp that has been shot at.
Every ship’s array contains a transponder [NEW-TECH], a sealed 1 W unit that cannot be switched off from the cab. It broadcasts the ship’s registry number, position and vector, its drive certificate (including the rated torch line; see Space Warfare Doctrine) and its plate state (Ship Module Standards) every 10 s, in bursts too small to be a channel for wildcode. The Interstellar Navigation Conventions and every polity’s traffic code require it. A ship with a dark transponder is not a private matter: ports will not berth her, the guilds will not insure her, and a naval picket treats her as a threat.
Each port and station runs a traffic control office [NEW-INSTITUTION] that assigns lanes, issues clearances and, near a berth, helps with the final approach. Its reach depends on the ship’s array:
A ship with no array, or with a dead one, cannot:
She can still dock manually at an uncontrolled pad, or ask for clearance from the station signal lamp [NEW-TECH]. Every port keeps a lamp as the analog backup: a 10 W aimed lamp with a 1 mrad beam delivers 1.3 mW m⁻² at 100 km, about 500,000 times the light of Vega, so any ship in view of the port sees it, and a ship with a cab canopy and a pair of eyes can read it. The code has three colours and four-flash words; a pilot learns it in her first term at the Pilots’ Guild. The lamp carries “wait”, “go”, “no”, “come in slowly” and “cease fire”, and little more, and a ship without an array answers with her nav lights and a hand lamp.
The array’s logic is a sub-Grey-Line core with ROM-burned input and output. The channel rate is a thousand times below the grey line, and the whole array draws 2 kW, one ten-thousandth of the 20 MW wildcode power threshold. In practice it is the physics of a 1 m dish, not the law, that sets the rate at range.
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