How to build a workable tiny scale hostile replicator?

[SWPIGWANG]

Okay, interstellar flight is difficult and colonization might face all kind of hazards.

It would be nice to send a piece of terraforming nanobot or tiberium or ork/zerg spores that gets the environment all transformed into the environment while killing unwanted natives at one go and make latter colonization a snap. How to actually do this outside of saying "because of nano" or "because of quantum" seems to have been overlooked quite a bit.

For all the fear of rouge self replicating nanobots what not, I think the most likely result is that scientists would release their greatest invention and find that some random bacteria just chew them up and split out the pieces. If the target planet have a biosphere any replicator is going to be under competition, and remote observation for light years out will never give enough detail to understand the ecosystem in detail. The replicator does not only need to survive the local environment, it also needs to carry out its larger mission successfully somehow, which means it can not randomly evolve (must have very robust replication), it must grow (quickly) in controlling resources and it must have great intelligence for tweaking parameters. (weather control in a cell?)
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So how can this be done? It actually seems impossible if one is competing on things that evolution can do well while is utterly specialized to their local environment, but there are probably tactics and designs that evolutions do not do where a intelligently designed replicator can take advantage of. What are those anyways and how can they be used?

Now there is things like genetic intelligence or multiple morphology within a replicator (like how a ork spore can generate entire ecosystem) but that alone probably won't over match specialized local systems all that fast.

[Lord of the Abyss]

Two ideas that come to mind.

1: Most simply, make it out of something that living organisms probably can't eat. Modern technology exists in the first place because there are a wide variety of materials that life finds inedible; you aren't likely to get up one day and find that a fungus has eaten your car.

2: Take a page from the evolutionary history of Earth, specifically the Oxygen Catastrophe. Design your replicator so it produces as a metabolic byproduct something destructive to the local life. Chlorine, for example; I've heard that suggestion several places.

[adam_grif]

On the other hand, things that living organisms can't eat generally aren't lying around in the open to be consumed for the purposes of replication by your replicator. Unless of course you're unleashing this on a technological world or the ruins of a formerly technological one.

[someone_else]

First: whatever is able to
-do very complex things
-learn stuff on its own
-reproduce

Is bound to fuck up horribly sooner or later. The faster they breed, the more likely they will fuck up everything in a short time.
Evolution will kick in and you get something like this or a world infested by malfunctioning terraforming nanobots.

Now, if the work has to be done in a century, you may be able to pull it off with a relevant part of your repilcators that get fucked up and must then be rooted out somewhay.
But if you give them thousands or even more years... yeah, forget to be able to set foot on that planet.

[someone_else]

So, how to postpone the inevitable to allow them to do their work before chaos takes possession of the planet?

Looking at how living stuff does the same trick (ripping-off nature, yay!), you can get an interesting clue.

Staminal cells in most organisms and ants/bees/termites have the a good trick:
Ability to reproduce is a well-protected privilege.
In both situations, the only cells/animals allowed to reproduce are not the same doing the dirty work. (also both reside in more protected areas) This means they are less exposed to eventual damage that could screw up the reproduction systems and make "malfunctioning" offpring.

In your case, you should have (well-defended) bot factories, that will create new units. This, coupled with half-decent communication, allows you to keep an eye on them. If one malfunctions, you can order other fabs to terminate/fix it.
Their number can be very high, but in any case will still be well below the number of individual drones, this allows you enough control on their reproduction to manage eventual screwups swiftly and silently .
A good pic of such a fab

[Nadrek]

May I suggest The War Against the Chtorr (by David Gerrold) as an example of a very similar style of interstellar invasion?

The basics are roughly as follows:
Create a large subterranean plant whose role is an incubator for other critters (or their predecessor forms). Its job is to be camouflaged, and to release each level of the ecology after the previous level has set in. Start at the microscopic level; your bacteria must start taking over for the local bacteria. Move up from there, one step at a time. Include a few not so bright forms of life whose primary purpose is to eat the locals.

Don't forget to handle the aquatic as well; fish that eat aircraft carriers are just cool.

Have this plant start off in a very tough, dormant, atmospheric re-entry capable form... and shove it through space, in bulk, sublight.

Optionally, start off with your bacteria _and_ a diverse set of plagues aimed at the most likely dominant forms of life, just to distract and weaken them.

Don't get too happy with the animal kingdom... "cotton candy plants" sort of like dandelions can be useful, too, especially if they all bloom at once (locusts swarm about at once...), are very nutritious, cast very fine (pink, just for fun) powder up into the atmosphere at once (which does bad things to jet intakes and other mechanical things... and gives a nasty lung infection as well)... and serves as an "all you can eat" buffet to the lowest level of "hatch a whole bunch of stuff at all once" day.

Oh; make sure it's flammable in the way of grain silo explosions.

Note: Patience is required. Check back in a century or two post-seeding.

https://secure.wikimedia.org/wikipedia/ ... the_Chtorr

http://tvtropes.org/pmwiki/pmwiki.php/M ... tTheChtorr