This is great, good read, thanks.

Rather than risk contamination of the space station, I'd keep everything a one way trip down to the planet. Everything is done with probes and remote controlled robots for exploring, research, building etc. Once the first person sits foot on the planet, everything is already ready to move in and live in safely.

@MichaelMortensen it'll be easier keeping the biohazard lab minimally contaminated if you can build it in orbit and fly a small selection of things up to it. It doesn't have to be part of the colony ship after all, it can can be an entirely separate station in a lower orbit that can be shoved into the atmosphere in the event of hollywood space plague.

@StarfishPrime I agree with Mike but not for the same reason. The biggest reason not to try to bring stuff back up to orbit is fuel cost. Efficiency is absolutely king in missions like this, and bringing anything back up out of the gravity well once it's down there is horribly expensive. Better to design your probes so that the only thing they need to send back is information.

@MorrisTheCat eh, by the time you've got the technological knowhow to plausibly launch a colony expedition with a multi-century timescale, down-and-back flights should be straightfoward. They're vastly simpler than interstellar travel.

@StarfishPrime simpler, sure, but unless you've solved reactionless drive, they're still a very inefficient way of doing things. I'm not saying they couldn't do down-and-back, I'm saying that in terms of the mass you have to ship from one star system to another, you don't want to do it.

@MorrisTheCat you're gonna want to go down and back evnetually. May as well bring it with you, rather than need to build it on site. If your system is principally driven by solar power and uses water as a reaction mass, the relative inefficiencies of the system are more or less irrelevant because nothing of use is lost and the duty cycles will be very low.

I think it would make a great book title: “A Multi-Trillion-Dollar, Multi-Century Suicide” It would be the story of this epic colonization effort that ends abruptly upon arrival for want of one engineering part.

@SRM Think Roanoke Colony, only a million times worse...

@SRM I believe its called "heroism" once the government has invested more than on million into getting their own people killed.

I can imaging some interesting literary tension to be gained from a scenario where the bio-assessment lab is landed and almost entirely automated except for one human to handle the things that can't be done well enough remotely or via automation. Imagine the stress of the poor sucker who drew lot #9 and has to survive where "Canaries 1-8" didn't make it.

+1 for "the top priority is not landing". Get your asteroid/comet mining and refinery operations going so you can build more habitats. Get your eggs out of one basket. Build orbital power and communications infrastructure so that whatever robots you send down can get right to work on the terraforming and testing. They can start farms with seeds you send down, and you can evaluate how the plants grow, before sending the test animals down, then feed the harvested plants to the animals.

"keep themselves and their descendants quarantines." - I've read the last word as Quarians, and it fitted perfectly ;)

Regarding down-and-up flights, I guess as soon as you arrive in the system you should capture a comet and start converting it into fuel using Solar power (or fusion if you have it). Then you don't have to worry about fuel.

` if mice and bunnies can't survive down there` -- Don't release them in the wild. Seriously. You might ruin a perfectly good ecosystem by introducing extremely agressive, extremely successful alien (from the POV of the new planet) vermin.

@Mindwin don't even need to release them into the wild. Their microbiome is enough to pollute an alien biosphere all by itself. See this answer for a related, but more negative point of view.

The upshot of an interstellar mission like this is that if you have the capability to do it, the planet itself is mostly a bonus. you already have the technological ability to construct a colony in orbit that will be mostly self-sufficient with only periodic resupplies of raw materials (such as minerals for your onboard agriculture) So your colony ship should effectively turn into a self-supporting space station and the study and slow colonisation and/or terraforming of the planet can be conducted at leisure.

@Mindwin successful human colonization will require replacing large areas of the native ecology from our microbiome up to our food animals, unavoidably.

I wonder why you would actually try to colonize a planet at this point, once you are adapted to life in space, why not stay there?

@Tobias its a reasonable point. Indeed, that would have been my answer if the OP had been about a generation ship rather than human popsicles.

The answer to that is more or less that a generational colony ship in orbit is functionally a small town and enough support structures to keep that going for a few hundred years at least. The goal is to expand and grow, so either you're going to want to build more orbital facilities, or you'll want to set up dirt-side. Planets are going to be easier and safer environments to work in by-and-large. The real answer is to do both. Build both space stations and planetary colonies to live in.

@Ruadhan I'd expect the colony ship to stay in orbit until it is utterly beyond repair, just as a backup. Some of the hazards of an alien world might take years or decades to manifest. You'd send colonists down in waves; having everyone go down to the planet at the same time just puts all your eggs in one basket. If the first lot all die of something, those left in orbit can spend a couple of decades studying it, working out a way to not die of it, and building their population back up until the younger generation who don't remember the horror of the last failure decide to try again.

Having two semi-independent communities like that would produce some interesting possibilties. I'm imagining a scenario where the colonists on the planet are regressing to more or less medieval technologies while the orbiting starship remains high-technology, mining the asteroids and moons for resources. Periodically descending on the ground-walkers to assert dominance, collect soil for agricultural purposes and maybe take up promising individuals to join their community (genetic diversity being the main reason). There's so many interesting stories that could come out of this setup

@anaximander The colony ship would be the nucleus of a permanent orbital facility. It will be the base for maintaining the satellite infrastructure and the asteroid/comet mining/refinery operations. Even if most of the space work is done by robots, there will be a few people living in orbit to manage the robots. And some of the original colonists won't be able to land on the planet due to poor health conditions. By the time the original ship is truly beyond repair (assuming that's even possible), it will be a small part of a far-larger station. It may be sort of a "museum" by then.

Not yet mentioned: Allergens! If it's an earthlike world with its own flora and fauna ecosystems, chances are pretty high and just about any interaction with it will have pretty good odds of causing an allergic reaction that will make peanut and shellfish allergies look like a head cold.

"The top priority is not landing, strangely enough." This is exactly why many stories about space colonisation aren't about a unified group of people colonising a new planet, but rather a few independent groups. If you're the only one coming, if you can rely on people cooperating, take your time - it vastly increases your chances of success. But if there's five different groups? Or if your group splinters when you arrive (Alpha Centauri, anyone? :))? You don't want to be the last guy who makes landfall. You might find there's no landing craft left :D

@Luaan if you can't do what you're told in a space station, someone is going to shoot you for the good of everyone else. The sort of idiots you're considering will not be invited to join the colony. People with a penchant for comitting suicide through stupidity, ignorance and impatience are unlikely to be welcome in space at all.

TL; DR: Watch "Alien: Covenant" and don't do anything like they do. They are extremely bad at space colonization. Do opposite.

@StarfishPrime That might work for a single disruptive individual. But humans don't work like that - they slowly build up cliques, and by the point you realize what you're doing, there's no going back. If you think this is simple idiocy, you have a lot to learn about how humans behave - if anything, it's quintessentially human, and probably part of what made us so "smart" in the first place.

@user28434 Reverse stupidity is still stupidity :)

+1 to all this. The big hurdle right now for space exploration is the obscenely high launch cost involved in getting stuff off the surface. If we have the resources to send a colonization expedition to another star system, it'd be insane not to build the infrastructure "upstairs" first rather than drop everything down the gravity well where we'd have to haul it out again to do anything useful with it.

@Luaan no. People like that will die. If they do not understand that rushing down to the planets surface will kill them, they will not be invited to join the expedition. You seem to be suggesting that humans are incapable of engaging in co-operative effort in a hazardous environment, which is clearly not the case, as they've done so for millenia.

@StarfishPrime No. I'm suggesting the way people choose to cooperate might not conform to what you would consider reasonable or cooperative, as they've done for millenia :)

@Luaan I, too, remember how Aldrin kicked Armstrong in the spuds to become first man on the moon. And remember all those times submarines suffered mutinies! Your idea of what behaviours will be tolerated comes from a very narrow realm of experience. It cannot exist in a space habitat. Everyone will die. A colony effort of this kind is the end product of a society already well adapted to co-operative living in a deadly environment. It will not be like the society you live in. People will not share your attitudes of "idiots gonna idiot". They can't. They'd be dead.

Good, but it should be noted that probes will probably already have collected lots of data such as weather, possibly before the colony ship ever even leaves Earth.