The following is a list of those techs which are often excluded in "hard sci-fi" for being too unrealistic, and my opinions on them. I'm not particularly strict on tech, as this does take place in the future where certain technologies are available/possible that may seem silly to us now, but
I do need a certain believability. I am not a "the only limit is our imagination" type of person, but I'm also not a "we don't know how this would work, so it must be impossible" person.
Before you create a nation that utilizes any of these technologies, please be sure you've read this. Some of these techs are straight-out banned, while others are allowed but only with certain conditions. None of these, however, are accepted without restriction.
Biological Ships:A.K.A. Living Ships, Organic Ships, Cyborg Ships, Bioships, and so onIf you are considering using bioships, I suggest you read this article, though it is not required:
sfworldbuilding.blogspot.com/2015/07/m..Whoever wrote that was far better than me at explaining this^^.

I'll admit, I have a love-hate relationship with this entire concept. On the one hand, it can be implausible and hard to accept from a scientific standpoint, but on the other hand,
holy fuck is it cool.
After spending 3 days attempting to decide whether bioships should be allowed or not, and stopping a few times to question the very definition of life, I've decided- almost against my better judgement- to accept bioships. I will, in all likelihood,
be using bioships in my own nation, but I will limit them to be realistic. If anyone else would like to use bioships, the following will apply.
I'll be going over whether this concept is even possible, the advantages/disadvantages that bioships would have, and the differences between biological and technological systems. Not necessarily in that order.
Disadvantages of bioships:First off, as previously discussed, I'm going to make the assumption that- for the purpose of this R.P.- all living things must be made from cells or cell-like structures. Therefore, a "bioship" is defined as an inhabitable, cell-made structure which can traverse space efficiently.
This has some obvious repercussions, due to the difference between the molecular structure of biological and nonbiological substances.
For one, it is
unlikely that a warp drive could be made from any organic material. I'm not going to go as far to say impossible, but it is so absurdly implausible that I won't allow it in this RP. A warp reactor like those scene in most sci-fi would totally and utterly destroy organic cells. The same goes for "hyperdrive", nuclear reactors, ion drives, and virtually any other normal propulsion system. It simply wouldn't work. Therefore, I must conclude that any ship made of only organic materials is either extremely slow, or it moves through other means. I'll leave it up to you to decide what those means are, but you must check with me first. It can't be magic.
Furthermore, most conventional weapons (mass-drivers/guns, lasers, plasma beams, and so on) would be difficult to make function properly. I
might allow a bioship using these sorts of weapons to exist if your nation is extremely advanced, or if you can give me a good explanation of how it works. More unusual forms of weaponry will be allowed, however, so don't be afraid to get creative. Maybe your ship has giant teeth?

Finally, cells are generally just weaker than metal. A lot weaker. Depending on the weaponry your opponent is using, they would probably be able to tear through your bioship like a knife through butter. Also, there's always the looming possibility of bio-weapons such as disease, poison, and the like- all of which a metal ship is immune to.
To recap: bioships are, in general, slow as a snail, weak as a snail, and defenseless as a snail that doesn't have a shell.
Advantages of Bioships:After I just spent several paragraphs tearing down the idea, you may wonder why anyone (especially me) would even consider a nation using bioships.
Well, stop and consider it for a moment. What do cells do best? That's right: they replicate themselves, and do so with relatively little energy. If you get certain types of living cells and provide it with the correct environment, you'll soon have two cells, then four, then eight, then sixteen... and so on.
This means that the first main advantage of bioships is fairly self-explanatory: self-healing. Although not all cells have this property, one could probably assume that any nation using bioships would have utilized replicating cells. As a direct result, the ship could heal damage fairly easily. If someone blasts a hole in the side of our dear bioship, it could gradually heal itself without the need for a repair crew. I don't think I need to tell you why that's a good thing.
The second advantage is perhaps not as obvious but far more important to a nation. A standard metal-and-composite hull would take tonnes of technology, resources, and effort to construct, making it an expensive item. Likewise repairs are probably difficult without the resources used in construction, and may never return full strength or performance. A bioship cleverly side-steps these problems. For construction it might need only a vat of nutrients, and can self-repair to a high standard. More advanced types might literally grow from eggs or embryos placed in the correct environment. If so, a fleet could require only time to construct (and probably less time than a metal ship), vastly reducing the cost and increasing the number of ships available.
To recap, bioships can heal themselves, and an entire fleet can be constructed at low cost. Think of the Zerg from Starcraft: they aren't the best but they come in swarms upon swarms.
How to fix the disadvantages:Now, if one wants to use a bioship, it will be possible to fix two of the mentioned disadvantages (lack of speed and difficulty with weapons) by making the ship a "cyborg"- allowing parts of the ship (weapons and warp drive, for example) to be made of metallic material while the rest of the ship is still organic. This way, you can have a warp drive for speed, but still somewhat benefit from the self-healing and cheapness of biological vessels. Unfortunately, nothing will ever completely fix their vulnerability.
I'm going to allow bioships, but only if you remember to adhere to the weaknesses. Even a "cyborg" ship will still be weaker in most ways than a metallic vessel, though it may make up for this in cheapness and healing. Bioships, I believe, may end up becoming the "dime a dozen" ships of this RP: they are easy and inexpensive but simultaneously weak and simple.
Replicators:
In Star Trek: The Next Generation, Captain Picard is often seen ordering a cup of Earl Grey Tea from a "replicator": a device that can instantly create anything by converting energy into matter. Food, weapons, people- you name it.
I'm not a physicist, and to be honest, I don't fully understand even half of the shit that would go into making a replicator. Therefore, since I am utterly unqualified to make a ruling in one direction or another, I'm going to allow replicators, but with several conditions.
1. Nobody starts off with replicators. It would be unfair. Replicators will have to be developed in-game
2. Replicators require a shit ton of energy, so much so that they can't be used on a day-to-day basis, as they are in Star Trek.
3. Replicators can only create simple patterns. Don't be tryin' to summon up an entire Starship, complete with crew and ammunition
Telepaths:
Ah, telepathy. It's the closest thing to magic seen in most Sci-fi. It's an amazing idea, but unfortunately, it has some limitations.
Most sci-fi with telepathy excuse it by claiming that the species evolved to possess this ability naturally, and thus is capable of reading the thoughts, or at least feeling the emotions, of every living thing they encounter (see: Deanna Troi). I call bullshit. Yes, I believe it would be possible for telepaths to exist, but I cannot think of any logical reason why they could sense the thoughts of
other species. I imagine that any telepathic species would communicate by sending mental signals out using an organ presumably located in their brain, which another member of that same species would "hear" using a similar organ.
Now tell me, what if Species A is able to telepathically communicate through these organs, but Species B does not have them, and therefore does not send out mental signals? How would Species A pick up on the thoughts of B?
Hint: they wouldn't.
Use telepaths all you want. Telepathy is cool. But don't attempt to say that your species can read the thoughts of every other species. It makes no sense.
The only possible exception is if the telepathy worked through some sort of technology, but we'll cross that bridge if we get to it

God Beings
There is not a single civilization in all of Earth's history which did not believe in some type of spiritual existence- at least, not for thousands of years. However, the general approach of sci-fi is normally atheistic or agnostic, as it is science-based and none have yet managed to prove the existence of a deity to the satisfaction of the general scientific community.
Yet, every now and then, a sci-fi will incorporate a nigh-omnipotent being, which is so beyond us (either due to technology or biology, who can say?) that it can only be described as God-like. It does not seem follow the rules of logic, nor the laws of physics- it simply does as it pleases, by some immeasurable force that we cannot understand.
The idea has potential, but it is not something I plan on doing within the scope of Fade, unless this RP goes on so long that we get bored and need a Q to keep us on our toes

Therefore, you are not allowed to create one. None of our nations should have any contact with one, nobody should have undeniable have proof of one, and nobody should let one enter at any point in the RP without my express, clear permission.
To recap: no Gods.
Universal Translators:There are hundreds of different species, all with different cultures, different biology, and different brains... and some device can magically understand them all instantly?
Please tell me you're joking.
Even with the most advanced Sci-fi technology, I see no way this could be possible save over-powered telepathy, and we already discussed the limitations of telepathy.
Furthermore, even if it were possible, I don't like the idea of everyone just understanding eachother off the bat. It's too convenient, too easy, and too boring.
So universal translators, although I WILL allow devices that can translate a language after being given some time and a lot of samples to work with. Thus, if you desire a machine that can translate speech for you, I will allow it granted that the machine does so only after spending several days or weeks attempting to understand the new language- and can translate it afterwords.
To recap: Universal translators are only allowed if they work slowly, over days or weeks.
I may add to this list as time goes on, so feel free to check every now and then. As a general rule, if you ever see me deny someone the right to create a certain tech, there's probably going to be a section on it here within the next fifteen minutes. I don't fuck around when it comes to limiting tech. I've seen it get out of hand before, and I really don't want that to happen here. Never, ever have your nation invent any new tech that
hasn't already been explained to me in it's entirety. Otherwise, the ban hammer is coming to fuck you up.
