Hello Folks,
I'm going to fall back on some of what is in GURPS and some of what I have stumbled across in reading here or there - along with just some basic thinking...
1) there is already research into artificial wombs. As such, I very much doubt that we're going to be limited to artificial insemination for the other genetic items.
2) genetic diversity has already been planned for by keeping various "biostock" available over a spread of time. As new "material" is needed, such biostock can be broken out as needed.
3) imagine taking a grav plate and making it curved. Imagine too, that you can stack them up so that you have three G's worth of gravity gradient. You can do any kind of manufacture from Zero-G to heavy centrifugal type separations. Add in plentiful electricity, and you have the means for a primative low scale metalurgy facility. This works for chemistry, this works for just about anything where you can get a gravity assist.
4) those grav plates? They can be used for other aspects including replacement pumps. Ie, on a world that is less than 1 G, a 1 G+ gravity gradient allows for fluids to flow uphill. Nifty no?
5) imagine having the ability to create CD readers or any other optical storage system for memory. You can have entire databases at your fingers tips such that a colony need not devolve all that far if at all, tech wise. Imagine too that certain infrastructure is required in order to have such a tech base. Under the circumstances - I don't see it as being all THAT difficult.
6) that colony, if it were planning on transplanting itself on another world, would have taken goods that were LOW maintenance interval items (ie very well designed) so as to be able to tolerate the extended duration of non-supply from the base tech. In addition, such machines as they'd take would include spare parts and the ability to MAKE spare parts - ie lathe machines, etc. As a GM, you might want to consider that this colony is going to be PLANNED in advance before they even launch the colony ship. As such, the colony WOULD have plans based on what they expect might be the circumstances involved in colonization.
7) why even worry about low berth switch outs? The only people who need to switch out during the trip are your crew. The "cargo" of colonists can easily be stored away so as to keep life support costs to a minimum. In addition, freeze your animals and the like so as to keep the costs of life support to a minimum there as well.
8) planting the colony:
a) in orbit, do a lot of photographing of the surface and search for the "ideal" site based on the colony's needs. Maintain at least a year's worth of observations to see if there is anything that should be known about the planet before you land the colony. In addition, since the ship is heading for a system, all sorts of observations regarding the target sun should have been made during the trip in. This way, if the target sun is a variable star - the colonists know this in advance. Phase I is to do testing of the soils by the experts aboard the ship (I'm assuming you have interface craft!). If needed, alien soil can be sterilized and then infected with the proper bacteria such that the crops needed by the colony can thrive. Get a small farm combine going to insure that when the first batch of colonists are awakened, that they aren't facing a famine situation from the get go or digging into the hard to replace initial stock of supplies.
Please note that anyone who has been preparing the colony site for the past few months will have been exposed to any potential pathogens and any initial plagues likely would have been dealt with in advance.
I could go on and on on the preparation of the colony site, but the gist of it is - conservative approaches can minimize dangers to a select few rather than the entire colony. As various specialities are needed, people are awakened from cold storage.
In all? Assuming that the colony was intended to survive anything, and assuming that the colony has access to high tech to start off with - I see no reason why the colony has to suffer any form of degradation unless - you have a Saboteur mixed in there.
Something to consider here on a sociological standpoint? Any society that increases its numbers using artificial wombs, and then separates the concept of parentage from child rearing is definitely going to develop differently than one that couples parenting with parentage. Another unintended side effect socially speaking is that if womb technology is commonplace - what is to keep the colony from keeping those womb machines in full operation and making more frozen zygotes?
An interesting undertaking there
