Why would we need Earthlike planets?

In terms of colonizing other star systems, wouldn't small objects like asteroids, moons, and dwarf planets make more sense to develop, as their low escape velocities mean it would be easier to extract and launch resources in space to be used on-orbit?

A colony ship immediately investing all of their resources into trying to build a self sustaining civilization at the bottom of a deep gravity well would make progress difficult, as they'd have to spend much more effort trying to synthesize fuels in order to shuttle mass back and forth from surface to orbit and vice versa, as well as requiring much more complex and difficult to build rocket systems. By contrast, a colony ship using several asteroids or moons to gather resources would be able to use relatively simple propulsion technology and wouldn't have to spend much time producing propellant as not much would be needed by comparison.

We already know that every element we use on Earth can be found in much greater concentrations and in much larger quantities than here on Earth, so why wouldn't the case be the same for other solar systems?

Maybe trying to find and study Earthlike planets has little or nothing to do with eventual colonization efforts. Finding asteroid belts and other small objects is probably far more important.

Earth-like planets provide atmospheric pressure, radiation shielding, and would have water. Colonizing is about sending supplies for eventual self-sustain, not so much about launching supplies back.

I'm talking about supplies the colony ship would use in space. If a colony ship is large and industrially capable enough to last through the several hundred year transit, it would be silly to abandon it once you arrived in your target solar system. Such a generation ship would have radiation shielding built in so it wouldn't be an issue unless you went too close to a Jupiter-like planet's magnetic field or something. It makes way more sense to continue living on the ship, using it's industrial capability along with resources from small objects to build new habitats and machinery etc.

Eventually you would be able to set up a new industrial base on one of the planets or moons of the system, but until then you'd want to spend your limited time and energy to increase your ship's habitable area and resource stocks so that if something goes wrong on one of your surface colonies you aren't fucked.

Also water is one of the most common substances in the solar system, and is probably just as common elsewhere. Small icy moons in our own solar system easily have more water than the entire planet Earth.

Yes, small icy moons in our own solar system easily have more liquid water than the entire planet Earth. No additional energy is required to obtain that water. It is immediately safe to consume, too. We also have the R&D, currency, technology, industry, and cooperative ability to build and maintain such a generational ship to operate. It's not as if developing more robust launch systems would pave the way for more feasible, efficient means of transit from surface to orbit, let alone provide new techniques through said innovation.

I'm sure there are no good reasons you would want to take advantage of a planet with its own magnetic field, atmosphere, hydrosphere, solar cycle, and potential deposits of more fuel, and mineral resources, than you would know what to do with. It makes more sense to take the time to build habitable mega-structures using those resources, and fly them out some odd hundred light years away, just to build more.

Are you reading what I'm writing?

First of all, we're going to filter any water we come across either way. Secondly, solid water ice is pretty close to as pure as water can get in a natural form, since water ice crystals exclude salt and other impurities as they form.

Obviously we currently can't build a generational ship. My question is in the hypothetical case of interstellar colonization, which strategy makes more sense, immediately cutting yourself off from the available resources of the asteroids comets and other small objects in that system by dumping all of your efforts into colonizing a world that is somewhat more habitable than Mars, OR is it better to remain a mostly space-based civilization until the material resources and industrial capability become available to allow large scale colonization of planets with high gravity?

Easier means of getting into orbit are a meme. Space elevators are possible on worlds with lower gravity, on worlds with Earthlike gravity it may be impossible and is certainly infeasible. There is only so much energy that can be released per unit mass of reactants in a chemical rocket, and with NTRs you can't achieve the same level of thrust as a chemical rocket, which means you can't reach a TWR of greater than 1. Better chemical engines compared to modern tech are possible, but they're more complex and you probably wouldn't want to rely on them 100% if the outcome of them failing is possibly going to result in the eventual ending of your colonization effort and the eventual death of every colonist. That's why I mentioned simpler propulsion technology, like pressure fed engines, that are not only extremely reliable but can easily be used to build SSTO vehicles that work on small objects. It's all about risk-reward here.

Earthlike does not mean Earth-clone. Those things you mention would be useful but their effect would already be supplied by the ship, and ALL resources are more common in space than on Earth, as stated.

>Are you reading
Well...
>water is one of the most common substances in the solar system
>Small icy moons in our own solar system easily have more water than the entire planet Earth

No mention of how the water would be processed, regardless of what state it would be in.

>we're going to filter any water we come across either way
>solid water ice is pretty close to as pure as water can get in a natural form
I mean, you did just type that. Just exactly a few moments ago.

>what makes more sense
I feel like by the time we are capable of constructing the kinds of facilities, vehicles, and structures to be a space-based civilization, we will be more than capable of colonizing worlds that are on par with Earth, or less than equivalent to Earth. Just saying.

If you've developed a way of creating super-materials to make sure your super-habitat doesn't tear itself apart while it spins to simulate gravity, assuming it doesn't generate its own gravity somehow, then you probably have taken the long and hard road of creating a colony, plus learned the feats of engineering, physics, chemistry, aspects of biology necessary... which means you more than likely have the technology and know-how to set up shop on just about any planet, anyways. Hypothetically, sure. Bring on the space habitat. It does make sense.

And I know Earth-like does not mean Earth-clone, but since an Earth-like planet could or could not have anything an Earth-clone definitely does, it makes sense to suggest that we would aim for the most Earth-clone-like planet, if we had the luxury to do so. That probably means it at least has a hydrosphere, and a magnetic field equivalent to Earth's own magnetic field. Otherwise, why go?

And why not harvest asteroids? I never said you couldn't. I'm just suggesting that, all in all, the hypothetical super-habitat is an entirely different means for an entirely different end.

Yea it's likely not important to find earth like planets once you are offplanet & have mass industries building space habitats

Reaching orbit from Earth is not at all "hard", nor is the energy cost particularly massive. So thats not the problem.

It just makes more sense to take advantage of what already exists, than striving to fine-tune something of that scale, for that many people, to deal with things like the gene pool, psychological health, and other avenues of social behavior that can lead to "space-crazy". That is the extant risk and reward we face, probably for the next hundred years or so. Hypothetically, that can all be done.

If you try to approach it with the finest touch of realism, then it gets increasingly complex from our current point in time. Those are all tall orders. And, I doubt we'll be reaching a solar system 40 light years away in less than a hundred million years, let alone 70.

I mean.

An user said it before. The intent is not to be ferrying between two points. It is to stay there, explore, understand, and develop a foothold for further development. The risk and reward comes with having a large canvas of a surface area to develop upon, with said canvas being a raw deposit of resources already. Free gravity. Free shielding, maybe. Maybe a free atmosphere. Maybe a free climate. No real need to climb back to orbit once you've settled- again, if we're doing anything outside our solar system, we will probably have the technology to build a proto-super-habitat. That probably means the majority of things we think are problematic today, will be trivial "tomorrow".

We could definitely do it your way, with the habitat. It's a definite option. But it just seems unnecessary. It's a different solution for a different problem, prompted by the same question that people answer with "live on (insert planet here). I bet privatized companies will mine asteroids and ship them to Earth or another colony, but I doubt anyone will mine on a planet and decide to ship it somewhere else, than distribute it amongst the colony so it can prosper.

Doing stuff in bulk is easy
3d printing large habitats from raw materials will be easy
Shipping around large objects in space is far easier than on a planets surface

People might CHOOSE to live on a earthlike planet in other Solar Systems, but its unlikely that that would be the first thing you do when arriving there

If people are choosing to live on an Earth-like planet, aren't they making the decision to live there, already? If they aren't choosing to go, then they don't go. If you are sending someone far, far away, they know they may as well not be coming back. They might intend to research the planet- but they can also end up dying there. They may as well get comfortable, and have a place to poop, eat, and sleep.

>3d printing large habitats from raw materials will be easy
So, how are we powering these habitats? How are we powering these printers? Who's overseeing all of the logistics here? Quality control? Margin of error? How are we assembling these fabricated parts? Structural integrity? Materials used? Technologies involved? Contingency plans for certain failure scenarios, like venting atmosphere, loss of pressure, radiation leaks, faulty parts, etc? Stress tests?

User error?

I don't doubt that it would be easier to construct things in space. I don't doubt that shipping large objects in space is easier, too. But that would both go for the habitat, and the colony ship meant to put colonists on another planet. Both can be large objects, both could be assembled in space.

In all likelihood, we will have mined what is closest to us, and then sent a colony ship to some destination, with everything we would have thought it needed. That probably includes the means to mine celestial bodies that are not planets or stars, after arriving at their destination.

But I don't see us building a truly permanent space habitat before we attempt to colonize a planet. I really only see the permanent aspect of that habitat coming from trying to build on a terrestrial surface that isn't at all welcoming- because it is easier, for example, to have gravity generated by a relatively large mass, than attempt to carry out R&D with more moving parts that can all fail in varying ways.