I_am_a_Spoon said:
Exploratory space travel is accomplished by an ever-largening network of millions/billions/trillions of nanotech reconnaissance drones, deployed omni-directionally from Earth. Each initial drone is able to replicate itself numerous times using pre-packaged materials, and replicated drones can salvage additional materials from extraterrestrial sources in order to continue the reproductive process. Each drone is able to act as a communications relay linking all drones back to a command nexus on Earth, and software updates broadcast from Earth allow far away drones to reconfigure the next generation of drones on the fly.
In all honesty I don't know how realistic all that is, it's one of the areas I still need to research properly...
Gonna have to stop you right there, because that idea triggered an alarm for me. I have to ask you to clarify, is this nano-drone array for the solar system, or to other systems? Because the two have different issues and rules you will have to follow.
If it is a array within the solar system, then realize that:
1: Just because it is the future doesn't mean you can ignore orbital mechanics. "omni-directional" isn't as straight forward as you put it. If you want to go to Mars, you don't just point the rocket where Mars is and just activate the thrust. It's much more complicated than that, you'd have to leave the orbit of the Earth, which means you will then be orbiting the Sun, then increase your velocity so your orbit will go "higher" (farther from your orbited body) to where Mars's orbits, and happen to reach that point as soon as Mars does. This is why NASA missions have set times of launch, if you wait a few days, the amount of fuel you'd need to change your orbital direction could be crippling.
2: Unless you dabble into quantum mechanics, relays that are far away from Earth will have to obey the speed of light. If your relays are at the distance of the Sun from the Earth, it will take 8 minutes and 20 seconds until the one at Earth gets it. This delay can be annoying, and could make live discussion between the Moon and Earth (1.3 second delay. both ways) aggravating, and conversations farther away more easily used with "email" style communication (IE, you sent, but don't expect a quick lively discussion. similar to a forum like this. only your post doesn't exist until a few minutes after you post it.). So quantum mechanics can change this, with a little something called quantum entanglement, which is an odd effect where two particles "linked" will react the same way, regardless of distance between the objects. This technology isn't even a technology, so if your universe has it, it will most likely not be miniaturized to the point that the nanobots use it.
3: Everything in space is moving. Your nanobots won't be frozen in space, they'd be orbiting the Sun with the planets, which means relays would need to know that in January, you need to send your message through a different path then on August. Basically, learn orbital mechanics. Learn Kepler's 3 laws, and play kerbal space program. It has a free demo, and is one of the few games that take into account gravity at the point of being unholy realistic.
If it is going past our realm, and to the stars themselves, the previous points apply, but there is more as well.
4: Stars are really far apart. Really REALLY far apart. unless your universe has FTL modes of travel, your nanobots will be under extreme issues that will render them useless. The nanobots will need some sort of mode of propulsion, and if they are truly "nano", then that thrust will be minuscule. They would be the equivalent of planting a tree, which won't give you its fruit for hundreds of thousands of years. They'd need to have enough thrust to overpower the gravity of the Sun (I assume they would be launched from a body orbiting Earth) and have the fuel to launch out of the orbit from the Sun. (you will always be orbiting the Sun until the gravitational pull from the nearest star is stronger than the Sun)
5: The time delay will be extremely crippling. If you had colonies, it'd be like the European colonies in the 1600's. You wouldn't know the colony's current state of affairs, but rather would know of its history. And this delay would be equivalent of how far away the colony is in light-time. If it is 4.3 light-years away, if you send a message, they will not respond until 8.6 years. The reports you would recieve from them would be 4.3 years old. If they died from famine, disaster, or mutiny, you would not know until 4.3 years after it happened, assuming they sent an emergency signal. The colony would have to be self-sufficient.
I hope that clarified a few things. I'd talk about the rest of the points, but I'd need to know more about your work. I don't even know if half of these points I made are even relevant to your work.