How to disable off-world signals?

Question

Request for Proposal

The planet to host our new colony occupies a section of the universe considered off-limits by numerous militant groups opposed to the safe harbor of innocent civilians and refugees. Should the colony be discovered, it will be summarily destroyed, resulting in the loss of life in the hundreds of thousands. We cannot count on the qualities of the host planet to protect against this outcome, so we must devise a reliable and persistent means to prevent signals from being dispatched from the vicinity of the host planet.

As such, we are submitting this Request for Proposal in search of a technology that meets the following requirements:

• Capable of deflecting, absorbing, or otherwise inhibiting all outbound artificial signals from the host planet and satellites in its orbit, including signals potentially emitted by hostile actors;
• Possesses a minimal detection rating to reduce the chance of accidental discovery;
• Utilizes a renewable energy source;
• Requires minimal maintenance; and
• Does not meaningfully impede the motion of spacefaring vessels.

Cost of the technology is no object. However, the system must be deployed and operational prior to the arrival of the first colonizing ship, which is scheduled to depart in six (6) calendar years and is expected to require ten (10) months to reach the host planet.

Thank you for your attention.

Irene Caulgwoff

Director of Technologies

Intergalactic Colonization Authority

Answer 1

Use wires as much as possible

For instance, don't broadcast television over the air, but instead use cable exclusively. Don't use wi-fi, just wired ethernet. No cell phones, just "landlines".

Shield everything

Big sources of electrical power will give off detectable signals. Shielding these isn't hard, however: A simple conductive, grounded shell around it will easily block the wayward signals.

Do the same for electrical and data transmission lines as well; not only will this improve your signal integrity anyway, but it will prevent leaking signals beyond the physical wires.

Your buildings should likewise be shielded to block any wayward signals. For extra protection, build underground to get the added protection of the ground itself.

When wireless communication is required, use as little power as possible

A walkie-talkie is handy for communicating over open distances of up to a couple of miles, but isn't going to be detectable from orbit, let alone out in deep space -- it's just too weak of a signal to stand out against the background noise.

You can further reduce the risk of detection by using directional transmitters, such as lasers and microwave transmitters, especially for those times when you just need to boost the power to get a signal to go farther.

Encrypt everything

There's lots of background noise in space, across every possible frequency and spectrum. When looking for signals from intelligent sources, then, the key is to look for patterns, and discard all the rest.

Enter encryption: A good encryption algorithm produces output that, ostensibly, is indistinguishable from randomness. You can't look at a block of such data and determine whether it is the works of William Shakespeare (encrypted), or just a whole bunch of random 1s and 0s.

Modern communications protocols require some non-encrypted header stuff, but if you were to mandate that everything that goes "on the wire" is always encrypted with, say, AES-256 using the common password "P@s5w0rd!", everyone can still decrypt and read it (notwithstanding additional encryption that might be being used for actual privacy) but the very nature of it being communication has now been effectively obfuscated.

Now, you'll of course have to modify or invent something new to encrypt not just digital 1s and 0s but also the analog carrier signals used as well, lest you produce the recognizable pattern of "highs" and "lows" that betray the use of digital technology, but that's pretty much just window dressing.

Encryption is not a panacea, however -- you will still have to rely as little as possible on wireless signals, and use as low power as possible, to minimize the risk of detection. Encryption just adds a little extra protection when you do need to use them.

Change frequencies regularly

At the same time, you'll want to avoid relying on certain frequencies too much, as even if it's unrecognizable the spike in certain frequencies can still betray you. This can be accomplished by using a variety of different frequencies for all methods of wireless communication, mixing the use of radio and microwave, and even using combinations thereof for the transmission of individual signals/messages. The result will be a very complicated communications infrastructure, but given the risk if you're discovered the complication is worth it.

Make your satellites rely heavily on optics

Signals from your satellites should use directional microwave; being aimed at the planet, there's very little risk of detection from beyond it, and what little does leak out will look like random noise thanks to the encryption you're using.

Sending data to your satellites is a bit trickier. It's hard to aim carefully at something a hundred or so kilometers straight up, and moving fast, and not accidentally send your signal into deep space where you risk revealing yourself.

So instead, equip your satellites with telescopes and have them aim at ground-based pads. These pads, using whatever technology you want, would produce optical patterns to communicate data (think those QR codes you see everywhere). Your pads should be able to quickly change their patterns to communicate new data, of course. You could even just use blinking lights. Detecting such a method of communication would be impossible for anyone who isn't already looking directly at your planet -- at which point they'll simply see your colony, your satellites, and secrecy is straight out the window anyway!

Stopping bad actors

To maintain the requirement that ships can come and go unimpeded, you can't shield the entire planet. (Besides, even if you say cost is no object, that's a monumentally costly construction project, not just in terms of money but in logistics and time as well.) The only way to stop someone maliciously transmitting from your planet and giving you away is strict internal security: Nobody but authorized personnel is permitted transmitters of any variety, for instance, monitored by heavy surveillance and enforced by harsh penalties. (Surveillance need not mean video cameras everywhere and your version of the NSA reading everybody's emails; since it's rogue transmissions you're worried about, simply detecting unauthorized transmitters -- which can be done with passive sensors -- is sufficient for this purpose. Up to you if you want the cameras and NSA in addition, though.)

You should also equip your satellites with precision orbit-to-surface weaponry. Whether that's lasers or kinetic weapons depends on available technology and your preferences, but the idea is to monitor for any unauthorized transmissions that could even remotely be detected from space, and quickly vaporize the source.

Working in your favor is the fact that even a high-powered transmission has to remain on for some time before anyone beyond your system can detect it, let alone identify with any accuracy the source. Your orbital weapons are more than responsive enough to deal with this threat.

This even assumes that we're dealing with highly advanced communications technology capable of far-faster-than-light communications. If you're limited to the types of communications we know of today, then you really just don't have anything to worry about, as it would take decades for the signal to reach even your nearest neighbor, and odds are that one's not inhabited anyway.

All this being said, nothing you can do can prevent someone on one of these ships that's coming and going from reporting your location to the authorities after they've left, so if bad actors is your threat you're pretty much hosed without blocking everyone from ever leaving your planet again.

Answer 2

Dear Ms Caulgwoff

My company has at its disposal an ideal material that fits the description you provide, including very high signal attenuation, minimal maintenance and permeability to space travel. We would be happy to tender a proposal for installing it on your planet. The name of the material in question is:

Rock^TM

Specifically we would build all habitations a significant distance underground. The Rock^TM would shield all signals used by the inhabitants for local communication. We would install a wired network system in the underground area for longer distance communication which, while expensive and less flexible than wireless communications, is infinitely preferable to being slaughtered by aliens. Longer range communication, outside the planet, could be done by extremely narrow band signals, detectable only at the specific place they are directed to.

Most activities would take place underground. Only trusted people would be permitted above ground. They would be limited in the communications they could use, and be closely monitored. A wide array of receivers would allow for very low power comms to be used above ground (since a receiver taking the signals underground would always be nearby).

Such an approach would not allow for satellites, and would restrict habitation to one planet, but this would be a small price to pay for the benefit of survival.

Yours

Malcolm Twisslethwaite

Cool Magma Inc.

Answer 3

There is no plausible technology which would fullfil all these requirements:

• do not suspiciously alter the spectral properties of the planet, neither for direct observation, nor when planet crosses the disk of the star viewed from a distance
• do not interfere with photosynthesis and result in ecological disaster
• do not generate so much heat that it would be suspicious for the observer or cook the planet

Any system other than magic or time travel is not going to work at blocking anything malicious while at the same time keeping the planet looking and functioning like a normal planet.

Therefore I propose extreme internal security, careful surveillance of everybody, passive monitoring of any transmissions, and rapid response to destroy any source of transmissions (orbital laser and kinetic weapons, supersonic drones). Also make any materials useful for building a high power transmitter to be controlled. So you can be sure you will find out if someone is going to phone home and can stop them, and also if someone manages to send something, they will be silenced rapidly and decisively.

Of course you also need normal precautions: No atmospheric pollution, only local power generation with small underground nuclear reactors. Only low power frequency hopping radio transmissions which won't reach space and are indistinguishable from noise when you don't know what signal you are looking for. Mostly optical communications anyway. Everything camouflaged and stealthed, especially any satellites disguised to look like rocks or old wrecks. Constant awareness od people, that being detected means death. Keeping people happy so they won't turn into rebels.

TL;DR Only way to stop transmissions is to stop anybody from sending them, by catching them first.

Answer 4

With the exception of allowing for easy passage of spaceships,the most effective way to shield the planet would be to surround it with a metamaterial shield.

The metamaterials can be refracted in any arbitrary direction according to the manufacturer's design. This could be enhanced with a secondary shield which refracts the light around the planet to prevent anyone from seeing it from space (at particular frequencies. 100% refraction would make the planet entirely dark...)

For an object the scale of a planet you would need some sort of orbital shield, either a single huge metamaterial "bubble" or millions of metamaterial elements in orbit.

Answer 5

I recommend heartily nuking the entire planet from orbit, such that the entire surface is far too radioactive for a colony to take root. The best defense is a strong offense.

Unfortunately, what you are looking to do is stop electromagnetic radiation. The only known way to do that is with a Faraday cage, but a Faraday cage around a planet is unreasonable based on your deployment timelines.

However, if a Faraday cage is an option, I highly recommend encasing the entire planet in a metallic shell. Airlock like structures can be placed to permit entry of space vehicles. Sunlight may be an issue, but your specifications did not include sunlight reaching the ground. If you are willing to accept a modest level of risk, you can open the shell in the direction of the sun to let light in, but paranoid people should have no problems working in the dark.

Your real solution is to weaken the "all communications must be stopped" requirements to something that is at least minimally reasonable to attain.

Answer 6

Hide your planet behind an event horizon. This will not only prevent radiaton from carrying information about your colony to the outside, but also malicious agents with freely moving spacefaring vessels will not be able to contact militant groups outside the event horizon. Note that a relativistic event horizon does not at all impede motion. It just warps the space-time.

Answer 7

The top rated answer on this page is the best answer for just external signals, this answer deals with bad actors.

First you will need two teams for this colony, one to build the colony and the second to settle it. Both teams will need a 3 year vetting process and one done before the other, you won't tell them they are being vetted during this time.

the vetting: after placing job notices, you will interview the people in person, and explain this is a 4 year job, you will have to pay them the whole time. after you interview those you wish to take with you rig up a ship and sit them in space for 2 years, claiming your traveling to the destination. During this time take your "NSA" and whenever an electrical device stronger than a handheld gaming device turns on you confiscate it. Anyone with a device will then be added to a watch list for the remainder of the vetting. during this 2 year period you must search deeply into each person, even more deeply than the "NSA" into refugees from Syria to the united states.

the construction team: this team will leave immediately to complete their vetting process when you start hiring settlers. when they arrive at the planet the settlement will be build between 1-2 miles below the surface; we are assuming this will be an average task for your level of technology. They will have, at most 2 years to build a settlement for 5,000 people below the surface, the amount is an estimate for large numbers of growth. These men will be brought back and then killed in space. remember only dead men tell no tales. You must still pay these men for service so that their families ask fewer questions.

settling: now you have a colony and vetted colonists. The next task is to take them to the settlement and dump them off, this is an underground settlement so hydroponics won't be enough to feed your population, we are assuming 1,000 to start. as your settlement grows you will need to expand out and down, if you go closer to the surface before your entrenched we will assume the settler compromised the settlement. we can use geothermal power to power the whole settlement and we will only allow limited power per person, anyone using more will be killed, quietly.

the bill for this will be high, 2,000 people being paid over 3 years at 120 hours a week, and the loss of a ship, not to mention the cost of the settlement to be built and the food for the settlement over an indefinite time.

Answer 8

For Blocking Signals

Find a means to ionize the atmosphere to either absorb, reflect or obscure all signals to/from the planet. Any communications which must be sent or received would have to be done from orbit and be routed through relays which are not in the system.

This ionization could also be useful in limiting what ships can enter the atmosphere. If it is adjustable, only let those you want to enter the atmosphere know what shielding is required.

Use Psychology

These militants obviously do not like innocents. I suggest to do something similar to what Schindler did in WWII. Hide in plain sight and don't make a colony which would be perceived to anything close to what is considered peaceful. Heck, the colony may even supply those militants with arms... which could also be used to gain some advantages against them if you're at war. Spin a good story about these being rebels.

There may be no need to hide structures should this ruse work. What means you use through regulations, technology, etc. to obscure or hide signals may not be questioned. Any militants on the planet may even willingly comply since this colony arms them, may be considered a safe harbor for them and could be "attacked" by your own forces.

Actual innocent civilians and refugees would need to (1) be hidden in secret camps/underground cities or (2) work in the arms factories. Hidden cities would have to have communications by hardwire only.

Answer 9

Malicious individuals are the biggest issue here, so...

Make them believe they did send the signal

Try to hijack their communication system before they send their signal, prevent it from going out and make them believe they received a response that the enemy fleet is coming. Then, they wont try to send further signals or try to escape the area where you can intercept the signal.

How ?

Nanobots

Make a cloud of Nanobots all around your colony that will infiltrate any incoming vessel and hijack their communication system before they can event detect you colony. How far that cloud covers depend on how much money and material you have, since you will need more nanobots the farther you go.

You can also fake signal both ways. If an enemy suddenly lost signal to one of their vessel, it will look suspicious, but if you can fake "All is OK" signals, they wont suspect a thing.

Answer 10

As you haven't stated anything about the conditions within the colony and only a rough estimate of the number (and needs) of the inhabitants:

Ban the use of electricity and convert the colony into a (more or less) pre-industrial society.

This would eliminate any electromagnetic signals emitting from the planet.

A pre-industial society has less impact on the environment, which might be detected optically (changes in the atmosphere or appearance of the surface).

If you really need electricity, it should be concentrated (both generation and use) and placed e.g. on the ocean floor or deep inside a cave in the mountain in order to use natural shielding (as well as artificial one like a faraday cage).

Last not least, be aware that regular incoming (or leaving) vessels into an otherwise uninhabited section of space may arouse suspicion

Answer 11

I suggest a carrot, a stick, and a warning system.

Carrot

People to live on the planet will be housed in immense domes, camouflaged to resemble the surrounding area, and outfitted lavishly. Further, the housing will extend underground; both the domes and the underground areas are shielded with Faraday cages, which eliminates accidental radio transmission.

Landing areas must all be equipped with a high-power (non-destructive) laser; this laser will target ships and act as a communication line. It will slave the ship to the landing system, which includes entirely disabling the radio system.

Stick

Throughout the system, self-propelled satellites will monitor for radio, laser, and other transmissions. Any transmission above radio silent operation will be immediately targeted and destroyed. Similarly, any ships on approach (and thus slaved to the landing area) diverting from the slave lock will result in their immediate destruction. Since you are already in the system "illegally", destroying incoming ships is not going to get you in any more trouble than before.

Finally, satellites above the planet will monitor for any radio signals and, once detected, will destroy the transmitter.

Every satellite will be disguised to prevent detection, so there will be no worry of one being discovered accidentally.

Warning system

It is impossible to completely stop the transmission of radio signals, barring time travel, which is an expensive and paradox-filled package. Once radio signals are detected, there is no way to keep them from leaving the system. Worse, any ship in the system can broadcast; or, if that isn't enough, a ship lightyears away from the system could broadcast a signal past (or in front of) the system to make it look as if the signal came from that system. There is no way to stop signals. If someone wanted to bring death and destruction, they could do it, and you would have absolutely no way to stop it - or even detect it, if it was outside the system.

However, radio waves are slow-moving, comparatively; it takes 5 hours for a radio link to reach Pluto from Earth, which means the residents of the system will have at least some time to hide. The moment a radio transmission is detected, its source will be destroyed, and the warning system will (via laser communication) warn every habitation. Each habitation will be stocked with single-use "flee ships", designed to exit the planet's gravity field and be picked up by a disguised rescue ship - the survivors will be planet-less again, but at least will have their lives.

Answer 12

If the only way they have is to pick you up via radio waves then you just need to cancel the radio waves out which you could do by broadcasting a reverse wave transmission so that they would match up and dissipate outside of where you want the signal to be available...

There probably is a way to do this, but I can't think of one that's "easy". The best I got is by creating a ring around the planet and setting off the second signal to cancel out the first as the first passes by the ring.

Another option would be to just build a shell around the planet and absorb the radio waves... but that really isn't a good idea.

Btw... if all they got is radiowaves to catch you with and you can build a ring around your planet, you're probably ok, so the questions is kinda moot.

Answer 13

Found a research station near the planet to research the long-term effects of artificial electromagnetic radiation on various life-forms. As part of the study the research station will produce accurate electromagnetic radiation that one would expect to be emitted from the whole range from a small colony to a modern fully colonized planet of that size.

Occasionally the research station must be resupplied with various high-tech gadgets that cannot otherwise be easily produced, such as processors or fuel for a fusion reactor to power the electromagnetic generators, or just news-items and entertainment.

The research is confidential. Unauthorized ships getting near the planet will face massive charges. Additionally our engineers have just found out that very high velocity asteroids are orbiting the nearby star in seemingly random fashion, so expect to occasionally lose a couple of ships trying to get close.