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In this universe humans have advanced far enough to be able to colonize planets in our system but not enough to do interstellar travel. Earth is united and they have moved beyond countries and borders.

Against a possible attack on any of the colonies on other planets, humans must have come up with a way to have a constantly open communications channel. The problem is, there will be times when planets are behind the sun (according to Earth).

For those special times I'm thinking of placing a relay station that will orbit the Sun with about a 90 degree lead from Earth in the same orbit as Earth. How realistic is this and what other methods could there be?

Edit: There are really good answers here and I think I should clarify a few things as the people who answered felt it necessary. You don't really need to read these if you feel like just writing a general answer, but if you want to add details, then these may interest you.

  • Earth is united, therefore small stuff like energy costs and supply lines will be taken care of by the UHF (United Humanity Front).
  • The UHF has colonized most of the planets that are plausible as colonies. Mercury is currently off limits but it's on the to-do list for the UHF.
  • If there's an asteroid that can be used for mining, there's either a mining base there or somewhere close-by and most moons are colonized, although neither has the equipment that a planet does.
  • Planets are independent of Earth in the sense that they handle their internal issues with their governments but they work more like a state government than anything else (so they're still bound by rules that the UHF sets but they can set their own rules too). This might seem irrelevant but this will also make sending messages to other planets and trusting them with those messages harder than it already is. (It would be like trusting Kansas to relay a message from DC to California, yeah it would most likely not be edited, but it might be.)
  • The UHF has been keeping a tight leash on the planets, there is no discontent among the general public but that's just because most people are living luxuriously and they wouldn't bother with an uprising. If there happened to be one, they wouldn't bother with stopping it either. There are rebel-ish groups but they're mostly irrelevant (the problems that will arise with the comm-system I'm choosing will have to do with a rebel group).
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    $\begingroup$ You're re-inventing George O Smith's Venus Equilateral series, which is over seventy years old. en.m.wikipedia.org/wiki/Venus_Equilateral $\endgroup$ – Mike Scott Jan 13 '17 at 12:07
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    $\begingroup$ I wasn't even aware of the book! Thank you! @MikeScott $\endgroup$ – John Hamilton Jan 13 '17 at 12:13
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    $\begingroup$ Even with just three planets inhabited (let's say Earth, Mars and a moon of Jupiter) the situation where you can't communicate directly and can't "bounce" a signal off another inhabited planet should be rather infrequent. Communication won't be fast and a close planet (like Mars) would experience jumps in communications delay when needing to bounce off a far "planet" (like a moon of Jupiter). The problem would decrease as more and more (nearby) planets are colonized. (Of course a moon has its own problems, but we should be able to solve that using artificial satellites around Jupiter.) $\endgroup$ – Jasper Jan 13 '17 at 14:47
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    $\begingroup$ @Jasper Look up Earth-Moon-Earth communication. Passive reflection off celestial bodies (specifically the Moon) is done by radio amateurs. It requires moderately high amounts of power (kilowatt-class) and huge antennas (for the necessary gain) for very low bandwidth communications (on the order of bits to tens of bits per second). Doing the same thing using different planets is simply not feasible. Remember that power delivered scales as distance squared, and you are taking that hit twice during a roundtrip. $\endgroup$ – a CVn Jan 13 '17 at 14:59
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    $\begingroup$ @MichaelKjörling I meant "bounce" in a figurative manner. You have people and equipment on those planets. Sent them the message and request them to forward it to your destination... $\endgroup$ – Jasper Jan 13 '17 at 15:02

11 Answers 11

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I am going to assume that by constant, you really mean constant as opposed to instantaneous. In other words, we are still bound by the speed of light propagation delay. We are also bound by the laws of orbital mechanics as currently understood.

Since you use "planets" plural, I take it that humanity has colonies on multiple planets and possibly moons, as opposed to just one outpost away from Earth or Earth-centric orbit (which we already have one of: the International Space Station).

I'm also going to, for simplicity's sake, assume that you have unlimited power output for the transmitters. In practice this is not going to be the case, but to a first order approximation to maintain reader suspension of disbelief, it works okay. Also, you can trade power output for data rate, as described by the Shannon–Hartley theorem, so if you can accept a lower data transmission rate, you can make do with less power (to a point).

Let's start with colonies only on the planets' surface, not any of the moons in the solar system. The problem here is that planets orbit the Sun with little regard to their respective orbital alignment with the other planets.

The easiest way to ensure that every planet is always in view of at least one communications relay satellite is probably to put the relay sats in an orbit around the Sun which is highly inclined relative to the solar system ecliptic (the imaginary disk that is formed by the orbits of the planets, which traces back to the protoplanetary disk of the solar system). A simple way to do that (well, "simple", but still expensive in terms of orbital maneuvering to get into place) would be to use a solar polar orbit. This is an orbit that goes across the poles of the Sun, rather than around the Sun's equator, at a 90 degree angle to the ecliptic.

Having three relay satellites in a solar polar orbit, 120 degrees out of phase, will ensure that there is always one within view of somewhere on every planet in the solar system, as the Sun will only block the view of one at any one time (as viewed from any particular planet). You may want a few extra for redundancy, but doing so does not significantly change the setup. Given that the other end of the link is close to the ecliptic, having three ensures that one is always within view of each planet, whereas with two, the situation could arise that one is behind the Sun and the other is directly in front of the Sun. That would almost certainly work from a geometric point of view, but in practice you would have serious trouble picking the signal out from the Sun's noise (see below).

Now, notice that I said somewhere on every planet. You are going to need a similar constellation in orbit around each planet where there is a human colony, to ensure that there is a satellite in view of every point on the surface where it is needed. At this point it comes down to a similar scenario to that described in Minimum number of satellites to image the entirety of Earth's surface at all times. It turns out that this is possible to do with four to six satellites (mostly depending on your ground station capabilities, I suppose; four is the absolute minimum required for the satellite constellation to be able to see every point on the surface all the time, but you also need particular spots on the surface to be able to communicate with at least one of the satellites at any given time). Again, you may want a few extra for redundancy, but solving this problem is not an insurmountable task.

Once you add colonies on the planets' moons or otherwise in orbit of the planets, you will need a reliable method for communication from the colony to the relay sats around the planet. For this, you can look to the Tracking and Data Relay Satellite System (TDRSS) for inspiration. Long story short, you need at least three satellites in geostationary orbit to maintain constant communications between any point in orbit and any point on the ground, after which getting the signal to the solar system relay sats is merely a matter of getting a signal (any signal) from point A to point B on the planet's or moon's surface, or between the TDRSS-like satellites. Once the signal is within view of one of the solar relay sats, have the satellite shoot it off toward the solar relay satellite, and the signal is off to its penultimate destination.

There are two big problems with this that your world's engineers would be facing, which I can think of.

First, the Sun is rather noisy well into the RF spectrum. That's a problem when the Sun is in line with the desired signal. So you will need to either place the Sun-orbiting satellites in a relatively high orbit around the Sun to ensure sufficient separation that high-gain antennas can select against the radio noise of the Sun, or extremely high-gain antennas at the ends of the links. I don't know which of these would be easier, but given that fighting the ecleptic is already difficult, either might well be worth the price to pay. Note that the higher-gain antennas require more accurate aiming, which will require more station-keeping, necessiting more reaction mass ("fuel") on-board the satellites for a given service life. Again, not insurmountable, but worth keeping in mind as it is an issue that real-life engineers would have to contend with and make tradeoffs in.

Second, solar polar orbit is hard. I alluded to this above, but don't dismiss the importance of it; it really is crazy hard. Let's say you want to place the Sun-orbiting relay satellites at the distance to the Sun of Venus (0.73 AU), with an inclination to the ecliptic of 90 degrees. First, you need to get to Venus' orbit, which can be accomplished with a Hohmann transfer (calculated based on a heliocentric, or Sun-centered, reference frame):

$$ r_1 = 1.00~\text{AU} \approx 149\,598\,023\,000~\text{m} \\ r_2 = 0.73~\text{AU} \approx 109\,206\,445\,611~\text{m} \\ \Delta v_1 = \sqrt{\frac{\mu_\text{Sun}}{r_1}} \left( \sqrt{\frac{2r_2}{r_1 + r_2}} - 1 \right) = \sqrt{\frac{1.3271244 \times 10^{20}}{149\,598\,023\,000}} \left( \sqrt{\frac{218\,412\,891\,222}{258\,804\,468\,611}} - 1 \right) \\ \Delta v_2 = \sqrt{\frac{\mu_\text{Sun}}{r_2}} \left( 1 - \sqrt{\frac{2r_1}{r_1 + r_2}} \right) = \sqrt{\frac{1.3271244 \times 10^{20}}{109\,206\,445\,611}} \left( 1 - \sqrt{\frac{299\,196\,046\,000}{258\,804\,468\,611}} \right) \\ \Delta v_1 \approx 2\,423~\text{m/s} \\ \Delta v_2 \approx 2\,622~\text{m/s} \\ \Delta v = \Delta v_1 + \Delta v_2 \approx 5\,045~\text{m/s} $$

which is managable (going to the Moon took a total of about 11 km/s delta-v for the trip out, plus some for landing and going back for a total delta-v budget of somewhere in the vicinity of 20 km/s split among the Saturn, service module, lunar module descent and lunar module ascent stages). This puts you in the neighborhood of Venus; not necessarily in Venus' actual location (that depends on orbital transfer timing, or what we refer to as launch windows), but at least approximately co-orbiting with it. Now, assume that your orbit is circular, and change its inclination by 90 degrees while maintaining its circularity (technically, its eccentricity), where $v = 35.02~\text{km/s}$ is Venus' orbital velocity around the Sun:

$$ \Delta v_i = 2v \sin\left({\frac{\Delta i}{2}}\right) = 70\,040~\text{m/s} \times \sin\left(\frac{90°}{2}\right) \approx 49\,526~\text{m/s} $$

So if your satellite-carrying spacecraft is already in Earth's orbit (which is not the same thing as an orbit around the Earth, but rather, co-orbiting the Sun with Earth), you need a total velocity change (delta-v) budget of about 54,600 m/s to enter a solar polar orbit at Venus' distance from the Sun, and that's after you apply almost 8 km/s plus drag losses to get to low Earth orbit. While there are almost certainly tricks you can use to cut down on how much of this you need to apply under power (with rocket engines running), that remains a massive undertaking. I wouldn't be the least bit surprised if you'd be looking at something similar to the Saturn C-8, which was about the same height but much bulkier than the Saturn V which sent Apollo towards the Moon.

Compare also Is it possible to communicate in space while the sun is between parties? on the Space Exploration SE.

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    $\begingroup$ Oh, that's a great idea. Three relays would make the plot that much more interesting. There would need to be a simultaneous-ish attack on the relays so that communications can be cut-off. Yeah, I'm liking this idea! $\endgroup$ – John Hamilton Jan 13 '17 at 12:19
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    $\begingroup$ Yeah I've read that part too. I'm thinking that they would be somewhere between Earth and Venus or Earth and Mars. I'm not sure if that would be a good distance or not, but it will give the suspension of disbelief. Resources are not infinite but solar energy technology would probably be enough for communications and the station systems. Of course, with this method, maintenance and supply lines are bigger problems. I'm thinking that they would have 3D printers for parts and supply ships coming in every few months or so. Anyway, that part is still under research. $\endgroup$ – John Hamilton Jan 13 '17 at 12:31
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    $\begingroup$ @JohnHamilton Yeah, I was thinking somewhere in the neighborhood of Venus or so. The specifics would depend on the capabilities of your link nodes, and don't significantly change the overall picture. IMO the only major problem with this is that attaining a solar polar orbit is hard. But given the capabilities of the people in your world, I suspect that the orbital maneuvering required to make something like this work would be within (or possibly even well within) their capabilities. $\endgroup$ – a CVn Jan 13 '17 at 12:34
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    $\begingroup$ @JohnHamilton: You wouldn't it a simultaneous attack, of the 3 relays, there are only 2 in view at most at any point in time, and depending how far from the Sun they are, there might only be 1 in view for some periods of time. Furthermore, this relay in view cannot by itself relay the message directly at all time, when the destination is on the other side of the Sun, it must relay toward another of the relays, which will then send to the destination. As you can see, a setup with 3 relays has plenty of SPOFs, and in the vicinity of the Sun (with its eruptions), it's not unlikely one goes down.. $\endgroup$ – Matthieu M. Jan 13 '17 at 16:31
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    $\begingroup$ @MatthieuM.: All three relays would practically always be visible from everywhere in the solar system. The sun coming between would be pretty rare. Note that you wouldn't put them anywhere near the sun; trying to pick a signal out from a source near the sun is really hard, which is precisely what building these relays is intended to avoid. $\endgroup$ – kundor Jan 14 '17 at 0:20
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Let the signals simply reflect off other planets, moons and shiny objects

In so-called Radar Astronomy, scientists send microwave signals as far away as to Mercury and Venus and are able to measure the signal reflected back at us! You may also have heard that a laser is bounced off a reflective plate on the Moon, left there by apollo astronauts.

What this goes to show, is that your civilization does not need a relay station around the sun, they only need a reflective object. A "mirror" in orbit would do fine, perhaps a chunk of ice further out, a polished comet? Or perhaps mirrors strewn around Mercury, it having no atmosphere.

There is some precedent to this in Earth orbit. In 1960, the US launched Echo 1 a highly reflective inflated satellite that allowed people on earth to communicate by bouncing radio signals off it.

Below is a picture of Echo 1 being tested at NASA and of LAGEOS 1, which was launched in 1971.

The LAGEOS satellite reflects laser light and was not intended as a communication relay. Instead it is used to measure distances. And as background for a scifi story perhaps? You see, the LAGEOS satellite is still orbiting earth but is expected to crash into our atmosphere in 8 million years. It contains a plaque designed by Carl Sagan, meant to be understood by any intelligent creatures living on the planet at that time. Will it be understood?

enter image description here enter image description here enter image description here

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  • $\begingroup$ See also space.stackexchange.com/a/15329/415 $\endgroup$ – a CVn Jan 13 '17 at 12:42
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    $\begingroup$ Ooh, I'm loving the idea of a huge disco ball going around the sun for "communication purposes" and "no we're not having parties there". Yeah, it could even be a conversation within the events that explains how they work and why they look the way they do. Maybe one side could always look to the sun and have solar panels and that way, it could also broadcast if it needs to. (Would itrequire maintenance in that case though? Hmm.) $\endgroup$ – John Hamilton Jan 13 '17 at 12:52
  • $\begingroup$ @JohnHamilton You are going to have major thermal control issues if your spacecraft is tidally locked with the Sun. $\endgroup$ – a CVn Jan 13 '17 at 13:33
  • $\begingroup$ Not suitable for interplanetary communication. You'll need several orders of magnitude higher transmission power to be able to reach the same data rate as with direct communication. $\endgroup$ – Karl Jan 13 '17 at 13:45
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    $\begingroup$ @MichaelKjörling oh, right. Then just an uncontrolled ball that revolves around itself would have to do. Although, if what Karl said is true, then this will be less logical than the others. (Well, in that case it will be fun factor over plausibility) $\endgroup$ – John Hamilton Jan 13 '17 at 15:05
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Three or four satellites around each planet, high enough so they see each other and one is always visible from any place (except polar latitudes) on the ground. For a reliable system, eight satellites might be a safer bet. You'd want to be able to connect to two of them to minimise loss during switchover.

Plus two (one is essentially redundant) additional communications platforms in earths Lagrange points 4 and 5. That way you always have at least two clear views at every spot in the solar system.

You'll want to add these lagrangian platforms to all planets so you can always connect directly between any of them. Saves bandwidth and delays.

The routing will be an interesting piece of applied math, not only calculating the best pathways, but especially the optimal time to switch between routes, depending on their variable bandwidth.

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  • $\begingroup$ Hmm, this seems solid in theory. Would it work on any spherical object with a size bigger than a moon? If so, this might just be the relay system I'm looking for. $\endgroup$ – John Hamilton Jan 13 '17 at 15:10
  • $\begingroup$ Sun is really big. "High enough" might be higher than stable orbit is possible. Have you checked the numbers? $\endgroup$ – Mołot Jan 13 '17 at 16:03
  • $\begingroup$ @Mołot Sun is big? And for four satellites you need an orbit that is a fraction of the planets diameter above its surface. Draw a square around the planet to get the picture. How could that not be a stable orbit?? $\endgroup$ – Karl Jan 13 '17 at 18:10
  • $\begingroup$ Four satellites might be too few if you want to cover the whole surface all the time, in any valley you would lose coverage sometimes, and away from the equator the angle would get bad. We use 24 for GPS. $\endgroup$ – user25818 Jan 14 '17 at 0:28
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    $\begingroup$ @notstoreboughtdirt Four satellites are sufficient to have a view of every point on the planet at all times, if you pick the orbits appropriately. Compare space.stackexchange.com/q/8414/415. GPS uses as many satellites as it does because part of its design goals mandates that every point near Earth's surface needs an absolute minimum of three, ideally four or more, satellites visible at all times. That's a different problem. $\endgroup$ – a CVn Jan 14 '17 at 12:11
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According to NASA, during Solar Conjunction:

They collect data from others and store it. In some cases, they continue sending data to Earth, knowing that some data will be lost.

OK, so this isn't great, but sun does not block communication totally.

Relay station on orbit that's not on ecliptic might help, but there will be problems with it:

  • Maintenance issues
  • Once upon a time it might be in solar conjunction with either of these planets

For this reasons, I'd prefer using another planet, or colonies in The Belt as relays. First, there will be many of them, and second, they will take care of their comm maintenance anyway. Of course, fees during conjunction will skyrocket, but well, anything comes with a price.

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    $\begingroup$ Yeah, that seems like a fair idea. The fees are unimportant as the "United Humanity Front" will take care of it and it would only ever cost anything to send a personal message instead of a governmental one. $\endgroup$ – John Hamilton Jan 13 '17 at 12:15
  • $\begingroup$ During conjunction, there is zero communication. It depends on solar activity (and exact position of source and target with respect to the ecliptic) how long that takes, and so probes keep sending data at the beginning and end. You can always re-send stuff that did not arrive correctly later, unless it's not stored anyway. $\endgroup$ – Karl Jan 13 '17 at 18:17
  • $\begingroup$ @Karl if NASA says some data will be lost, and you say all data will be lost, then it's NASA for me. Sorry, but I believe them more when it comes to space exploration. $\endgroup$ – Mołot Jan 13 '17 at 18:25
  • $\begingroup$ How do you expect to communicate through the sun? It might be that the orbit nodes are such that one conjunction leads the line of sight so far obove or under the sun that you retain some signal. Next time no such luck. Not what i'd call constant communication. $\endgroup$ – Karl Jan 14 '17 at 0:12
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This is not a realistic problem.

You haven't clearly explained why the communication channel is necessary, but from the context of your question I assume it's so Earth can launch a defense fleet to defend the colony planet.

Let's consider Mars, since it is the closest planet that is remotely habitable (the surface of Venus averaging 467 degrees Celcius, hot enough to melt lead). The optimal minimum-energy launch window occurs roughly once every two years and lasts roughly a month. This occurs at a point when the difference in orbit between the two planets is 44 degrees, meaning the sun is certainly not obscuring line-of-sight between the two planets. This transfer flight plan takes roughly 260 days to reach Mars. Faster flight plans are possible, but they require considerably more energy.

With a one-month transfer window that only occurs every two years, your odds of the alien attack coup occurring at the optimum time are very low, and even then if you get lucky it's going to take two-thirds of a year to reach Mars.

Furthermore, if I understand this article correctly, we only lose line-of-sight communication with Mars for a few days every two years. If it takes well over half a year to fly to Mars in the best case, and Mars is never out of sight for more than a few days, that loss of communication is extremely insignificant.

If your aliens attack coup takes place on a further planet, it will take significantly longer for a fleet from Earth to arrive. To give you a sense of scale, Jupiter is the next planet out in the solar system after Mars, and it takes six years to fly to Jupiter.

If your alien species is advanced enough to launch an attack from outside our solar system, they are probably intelligent enough to plan their attack in such a way that maximizes the time it would take a defense force from Earth to arrive at the planet. So travel time will probably be closer to worst-case scenario than best-case.

tl;dr

It takes so long to fly to another planet that short gaps in communication when the planet is eclipsed behind the sun are not worth worrying about.

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  • $\begingroup$ This ended up a little rambling and probably not organized the best, but I'm too tired to fix it now. I hope it's helpful. $\endgroup$ – user45623 Jan 14 '17 at 11:01
  • $\begingroup$ The tl;dr is almost longer than the rest of the answer, which kinda defeats the purpose of a "tl;dr". I suggest editing $\endgroup$ – xDaizu Feb 7 '17 at 7:30
  • $\begingroup$ @xDaizu I originally wrote this answer while I was tired and it barely made sense. When I revised it, I shortened the first part and extended the tldr; I think it is more coherent now but you're right that the 'summary' isn't any shorter than the 'body'. However, the asker has already accepted a different answer, and my answer wasn't completely relevant because I had misunderstood some of the context of the question (I thought his colonies were being attacked by aliens but the question is related to coups) $\endgroup$ – user45623 Feb 7 '17 at 21:29
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    $\begingroup$ @xDaizu Eh, I revised it anyway. $\endgroup$ – user45623 Feb 7 '17 at 21:35
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Why not model TCP/IP Ethernet protocol. where you can have many transmitters, and relay/routers that will build a resiliant routing table to send communications to the fastest route available at the time

This will give fault tolerance and allow for adjustment to communication stations going down.

Focused directional transmissions would take less energy but more maintenance. Also let's not assume we are alone in the universe, focused transmissions might keep most transmissions virtually silent outside of the intended target. I can only assume like people some other worlders are good and some are not.

There is plenty of sun for power outside our atmosphere. so earth satellites and moon stations might be the first layer.

Sometimes Mars is close to our orbit and sometimes it is on the other side of the sun, which is far. so communication times will vary from anyplace other than the moon.

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  • $\begingroup$ TCP is not useful for interplanetary networking because of the delays inherent in speed-of-light communications at the distances involved. TCP is designed for networks where transit time is negligible. While it can in theory be used in networks where transit time is significant, the delays make it a less useful option than other alternatives. Compare for example Information Exchange In Space and End-user experience and prominent use cases of robust interplanetary internet. $\endgroup$ – a CVn Jan 14 '17 at 12:16
  • $\begingroup$ tcp has been used over slow unreliable transports, see also RFC2549 :) $\endgroup$ – Jasen Jan 15 '17 at 12:02
  • $\begingroup$ @Jasen I sincerely hope that you realize that RFC 1149 and 2549 are both April Fool's RFCs. $\endgroup$ – a CVn Jan 15 '17 at 13:52
  • $\begingroup$ yeah, but some fool tried it,and it worked. $\endgroup$ – Jasen Jan 16 '17 at 5:56
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put 2 an artifical planets (can't call them a satellites) in an elliprical polar orbit around the sun, they'll spend most of their time ouside the eccliptic, and thus atleast one should be reachable at any time

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  • $\begingroup$ Wouldn't that require too many resources? Even if we all got together, it would be a tad too much just for a comm system. $\endgroup$ – John Hamilton Jan 14 '17 at 11:24
  • $\begingroup$ these would be machines or possibly crewed space platforms, (satellites orbit planets, these orbit the Sun) if you've got energy to travel between planets this should be possible too. $\endgroup$ – Jasen Jan 14 '17 at 11:28
  • $\begingroup$ This basically makes the same suggestion as my answer, except you use two instead of three. Note that two are not necessarily sufficient to ensure constant communications (as desired by the OP); it's perfectly possible for one to be occluded by the Sun (as viewed from any particular planet) while the other is in line with the Sun (degrading signal strength possibly to the point of practical unusability). And as you can see in my answer, entering a solar polar orbit is crazy expensive in terms of delta-v. $\endgroup$ – a CVn Jan 14 '17 at 12:30
  • $\begingroup$ use signifigantly elliptical orbits, and not near the sun, maybe somewhere between venus and mercury. so the platforms will spend 1/4 their time to the south of the the sun and 3/4 to the north, then if the platforms are evenly spaced on the orbit there will always be one, and often two significantly north of the sun. (see also Keppler's law) $\endgroup$ – Jasen Jan 15 '17 at 12:00
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Maybe a mesh network in or near the asteroid belt? Lots and lots of very small, very cheap and also cheaply replaceable relays networking the entire belt increases the odds of being line of sight with one or more of the satellites and all of the satellites being line of sight with at least one other. Sow them out slightly above or below the plane of the ecliptic. The redundancy factor means that the system would be much more robust than a handful of relay satellites. The downside is that the speed of light is a non-trivial factor. By the time the message reaches earth, the aliens have packed all of the colonists into TV dinners.

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    $\begingroup$ The big cost is more likely to be in putting the satellites into their respective orbits, not manufacturing, especially if you are able to churn out a bundle of them at once with effectively the same design. $\endgroup$ – a CVn Jan 14 '17 at 16:45
  • $\begingroup$ Launch a "launcher" that contains hundreds or thousands of the buggers. It gets to the approximate area and then spits them out at intervals. Since they are small and cheap, don't worry about too much precision. You want quantity. $\endgroup$ – Paul TIKI Jan 16 '17 at 15:00
  • $\begingroup$ What matters is mass, delta-v requirement and delta-v capability. Whether that mass is in a single payload or thousands of distinct payloads is largely irrelevant. Also, while not impossible, you'd need some fancy flying in the interim because objects in space generally refuse to stay put. All that fancy flying costs fuel, which brings you back to square one: delta-v budget. $\endgroup$ – a CVn Jan 16 '17 at 15:55
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    $\begingroup$ I'm thinking that none of these is permanent and each would only have a limited life, so to speak. If the orbit decays, who cares. Get a bunch of them up in one carrier at approximately orbital velocity, and then scatter them, even if the delta v to the carrier is pretty much zero. Maybe set up production stations on individual asteroids in the the belt and have them slung out from there. That would drastically reduce the delta v budget. $\endgroup$ – Paul TIKI Jan 16 '17 at 16:16
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It's simple! Look at the Star Fox 64 map.

Install a big antenna on the planets that the UHF has colonized. They will be connected to one each other, avoiding the Sun. If there is a planet trying to communicate with one behind the Sun, simply find another relay station (planet) to get your message to the receptor planet.

Look at this:

the Star Fox 64 map

Of course, there is software controlling the RF.

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I would recommend a similar approach to actual phone lines nowadays: an array of repeaters spread across all planets (right now they're just on top of buildings or mountains) so even if the Sun is between the original signal and the Earth there will be repeaters all around it.

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  • $\begingroup$ @Frostfyre thanks for the correction, I didn't realize grammar was so important here. As you may have noticed english isn't my mother tongue. Anyway, I'll try to be more careful in the future. $\endgroup$ – dibiler Jan 16 '17 at 8:06
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There is a real phenomenon that defies the limitations imposed by the speed of light: Quantum entanglement, where two quantum entangled particles function in such a manner, that a state change in one of the particles instantaneously affects the other. This phenomenon theoretically ignores any kind of distance, so it would be an ideal basis for communication. If it could be leveraged for such a purpose, one such pair would provide unlimited bandwidth between two points. So, you could create an interplanetary or even intergalactic internet using that.

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    $\begingroup$ Or not. $\endgroup$ – Mołot Jan 13 '17 at 15:07
  • $\begingroup$ Well of course it is, for the moment, impossible. This is supposed to be fiction, after all. $\endgroup$ – Ioannis Karadimas Jan 13 '17 at 15:37
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    $\begingroup$ This theorem, if true, means it will forever stay impossible. Of course this method may be used as nice handwavium. $\endgroup$ – Mołot Jan 13 '17 at 15:58
  • $\begingroup$ this is not possible, as @Mołot cryptically stated with his wikipedia reference. $\endgroup$ – james turner Jan 13 '17 at 20:52
  • $\begingroup$ @jamesturner i wasn't trying to be cryptic. Simply, whole content of that article is way too much for a comment, and anything less wouldn't be complete, $\endgroup$ – Mołot Jan 13 '17 at 22:55

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