It appears that there is no method of communicating over interplanetary distances for small ships in Eclipse Phase. A large radio has a range of 5000 km in open space (page 298), a laser or microwave link a range of 500 km (p. 314). Neutrino communicators require a potent energy source and thus are fitted only on large spacecraft (p. 314 again). Last communication method described is a QE communicator, which is quite expensive for regular mesh-browsing activities.

Nowadays, we have Deep Space Network that allows us to receive interplanetary communications. It requires a large amount of distributed sensors, and probably relies on low data load overall. Future tech can probably compensate for increased demand... maybe?

  1. Should it be assumed that ranges given for radio rely on single receiver, and can be effectively ignored when dealing with interplanetary mesh, thus allowing a spaceship to communicate (via relays if necessary) with mesh using radio waves?

  2. Are there other means of communication not covered by the book (which is not that focused on owning a spaceship) but plausible given the portrayed technology level? For instance, modern-day laser communication seems more than capable of handling the distances of our Solar system - but how affordable are they?

  3. Fundamentally, the question comes down to the following: can a spaceship flying between planets communicate with their mesh without using the expensive QE comms or demanding neutrino broadcasts, or is it effectively on its own until it gets into orbit?

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    \$\begingroup\$ Keep in mind that a lot of the information in the rulebooks is for equipment player characters are likely to get their hands on; It's entirely possible there are other communications devices commonly used by background NPCs but that wouldn't have a useful place in any in-game situations the game's developers thought about. Also note the philosophy that the rules should only be consulted when an answer based on reasonable assumptions isn't readily forthcoming; Not everyone agrees with how to apply it, but it's useful in a lot of games. \$\endgroup\$ – GMJoe Apr 2 '14 at 4:51

The data given in Eclipse Phase do seem to fly in the face of existing facts, unfortunately. As you note, existing laser link technology is already up to the task. The MESSENGER probe established laser link with a terrestrial station(!) from 24 million km in 2006. That's not even a quarter of an AU, but it's over four orders of magnitude further than what the manual says. It had a modest power supply and from what I can tell the laser communication hardware was fairly small. Certainly it wasn't the 100 m³ required for a neutrino receiver, as the entire satellite was not that large.

(As a side note: the size of neutrino comm tech is not consistent. EP p.314 says the smallest neutrino receiver 100 m³ while a transceiver is 8 m³ — but a transceiver necessarily includes a receiver. Meanwhile, the "neutrino retreat" receiver is 1 m³ (Gatecrashing, p154).)

Geostationary orbit is around 40,000 km up. According to the Eclipse Phase rules, it's not even clear how a small craft could communicate at that range. A truck-sized radio has a range of "many thousands of miles," which might cut it. (Miles??)

We've got two options: fix the rules or explain why they're so.

You might say that a laser link would, of course, work, but that you'd need to have someone keeping a point-to-point laser communication array ready for your ship. (I presume that you can't have an arbitrary number of laser links to a single target, although I Am Not a Physicist™.)

You might just grossly limit the bandwidth available on interplanetary lightspeed comms. "Sure, you can make a low-quality (and obviously high-latency) voice call, but you can't do anything else useful on the mesh."

The question to ask yourself is how disruptive the decision to diverge from the source material will be. My guess is "not very," no matter how far you diverge. Spaceship travel is not a popular thing to do, so it is probably not likely to affect most scenarios. If you do end up having PCs jaunting between planets on four-man ships, I think the best thing to do is to decide whether it's more dramatic or more annoying to have them isolated from the mesh. Personally, I think I'd go for the "low bandwidth, limited functions" uplink.

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    \$\begingroup\$ You're right about not being able to have multiple laser links—painting one target with two laser messages just interferes with each other. Unless of course you coordinate them so that you use or avoid the interference… but that's the same as doing two links on one laser beam with twice the power, and presumably you're already giving it max power. Because of how much even lasers spread out over interplanetary distances, you need two widely-spaced (many km apart at least) receivers to double up on laser links without using interference management that would make them redundant. \$\endgroup\$ – SevenSidedDie Apr 1 '14 at 23:53
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    \$\begingroup\$ The PCs in our game actually have a small ship (via the trait in Transhuman), hence the question. Limited mesh access has already been a plot point once. Figuring out why things work they way they do is part of the fun of EP for me, and hopefully for my players. \$\endgroup\$ – Magician Apr 2 '14 at 3:05

This sorta stuff falls under the "Not Fun, Forget It" rule. If you're worrying about it, then it isn't fun. Realistically, they'd be able to connect to Meshes, but it'd be slow. You would have several minutes to several hours of delay between transmitting and receiving data. So, possible, but a pain.

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    \$\begingroup\$ This answer does not really try to answer the question posed. Please read our help center to understand the stack exchange methodology. \$\endgroup\$ – mxyzplk Apr 3 '14 at 22:53

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