In the near future, humanity has spread out across the Solar System. A new planet is discovered, let's say 30 light years away, that shows it to be Earth-like and could harbor Earth life without too much issues. A research expedition with a variety of specialists is put together to go check it out. The plan is to observe and scout from orbit for a year or so and then send specialists down on the planet.

Let's also say that we now have an experimental drive that lets us accelerate to 0.4 times the speed of light, so we can get to this planet in 75 years. In that time, the researchers will be in cryostasis. A group of trillionaires and government organizations have put a lot of money together top fund this endeavor.

So does it make sense that they'd maybe want to send some "regular" humans colonists along for the ride? Since there is such a big chance that the planet can harbor human life without terraforming or hardcore protection from the elements, wouldn't it be a good idea to send some civilians along, so that after the initial recon and research is done, they can start building a civilization on the planet?

Is this something that those who put the expedition together would consider?

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    $\begingroup$ One thing that might be an issue. Earth like would probably (unless you want to make it an Earth clone) be quite different in detail from the Earth with a different biochemistry originating from a different biogenisis and a different evolutionary path. So I would not bet on the environment being friendly for the colonists. Everything might be toxic and would be well adapted to the unique environment of the Earth like planet so would out compete Earth life. It would be very difficult, they might well have to live in domes. $\endgroup$
    – Slarty
    Commented May 3, 2020 at 20:28
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    $\begingroup$ There are so many fundamental issues with 'Another Earth' scenarios. If it's habitable; then you need a reason that it hasn't developed life. If it's got life on it, that's a huge problem. You need a really contrived reason to have an oxygen atmosphere without life. If your planet doesn't have oxygen to start, it will take a complete turn over of the crust (millions to billion) years to get the rocks oxygenated enough to not suck the free oxygen out of the atmosphere. Banded iron formations. There's a worldbuilding wiki age in here that details some of these issues. $\endgroup$
    – user3082
    Commented May 4, 2020 at 5:23

5 Answers 5


They might well consider it, but the right decision would depend on details you have not specified.

  • How long would the colonists have to survive on that planet before more colonists could be delivered?

  • How much will it cost to transport those colonists and their necessary equipment, to the planet, and back again if it turns out to be unsuitable?

  • What is the purpose of colonisation: profit, a backup home for humanity, or some other reason?

  • How good is the available medical technology, and how realistic is your setting? It's possible, for example, that humans might have severe allergies to proteins from an independently evolved ecosystem, which might make colonisation impossible.

The answers to these questions are your prerogative as author. They don't have standard and correct answers for all situations.

  • $\begingroup$ Also, which is plan B in case the planet happens to be uninhabitable or anything else prevents colonization? Return the colonist to Earth? Have them wait for centuries for a rescue ship that perhaps will never arrive? Follow up to another solar system? Send the ship into that planet's sun? $\endgroup$
    – SJuan76
    Commented May 3, 2020 at 20:39
  • $\begingroup$ Also, how much does it cost to build the spaceship, and can the colonisers afford to send two ships instead of one? There will always be volunteers for this kind of mission. $\endgroup$
    – user7868
    Commented May 4, 2020 at 5:37

Yes it would make sense to bring support engineers in the form of colonists.

It all depends on how large your expedition force is and how long surveying will take but... Assuming the expedition is very expensive and the amount of travel time involved, surveying will probably take several years to decades. Seeing that a round trip takes 150 years you don't want to rush the research once you are there. With an expensive research project of at least several years, you want top-notch researchers but also a complete support staff. You will need everything from cleaners, cooks to maintenance technicians.

It is these people that can perform a double function. While starting the research project a lot will need to be set up and you will people doing this. After everything is set up, suddenly you need fewer people and the scientist can do their work with only some help. This gives the would-be colonists time to begin colonizing while also keeping their normal day job.

In this way bringing colonists/support staff helps the mission get off the ground faster and let scientist focus on their main task. Since the ultimate goal is colonization, kick-starting it with a select group will certainly be worth the cost. Possibly even a science project of its own, seeing how colonists deal with foreign nature. And if the worst case happens and it is not colonizable at all the colonist can come back with the scientist while still having fulfilled a necessary role.


Not exactly

You have access to cryostasis, so that gets one of the major hurdles out of the way, but there's another issue - energy. It takes a lot of energy and resources to launch space expeditions, so if you're sending a survey team, you don't want any dead weight with the survey team, and every additional system is an additional chance that something goes wrong. Not to mention that you'll need to be able to take the researchers back in case something goes wrong, and that's a lot more fuel.

However, there's nothing stopping you from sending a 'just-in-case' mission a year after the expedition team leaves, such that they'll arrive exactly when the expedition finished, replete with it's own resources.


I'll elaborate more on this answer later, but I'd say yes, it does make sense to send colonists along for the ride. You see, your interstellar starship is an expensive build, even for the highly automated space factories churning out habitat components from target asteroids.

So expensive is the R&D of the starship's propulsion and other works that the company that built the starship did so with partial private backing. A nearby habitable world is an enticing venture for the rich voyagers of the solar system, and the extra living quarters, supplies, CO2 scrubbers and environment-sustaining machinery, etc. needed to maintain these people will cost far less than the price of the tickets to board this craft, saving the company money in the end.


It Depends...

There are a TON of variables that would go into the decision to send colonists, most of which have little to do with the actual planet. If we assume in your future scenario that Mars has been colonized, people are already accustomed to living in enclosed environments shut off from their world. Compared to Mars, an alien but Earth-like world where you can't interact with the native life because it's incompatible might seem pretty pleasant. Assuming oxygen, liquid water, Earth-like temps, Earth gravity, and not-entirely incompatible life (no aggressive sentients, or hyper-acidic bacteria, name your poison) even an incompatible world is worth colonizing - compared to Mars.

That being said, You can look at the various biosphere projects and see what a pain it can be to live in an isolated environment. Compares to Earth, it would be a sucky, isolated existence with little hope of relief from home. Now you are sentencing your children to that - FOREVER. Here are a few of the variables I can think of.

  • Panspermia - If you assume all life in the universe is related to some primordial starter matrix (unlikely) then the biology may be compatible, in principle. This ideal situation gives you the best options. But you wouldn't know this until you got there. Potential colonists would have to be prepared to live their future lives out either in a sealed base or space station if the planet isn't an option.
  • Terran environmental failure - If the Earth looks like it may be Dying, there's a HUGE motivation to send colonists ANYWHERE. Even if they take up residence in an asteroid belt, you still want to scatter your seeds everwhere and see what sticks.
  • Pure science - While you can't be sure of the life your colonists might lead, ideological scientists might decide the planet needs to be studied permanently. They would want a permanent human presence to continue their work.
  • No return trip - If your ship is essentially a one-way voyage, and the fuel is gone when you arrive, your voyage becomes cheaper in monetary cost, but more expensive in human cost. By planning a colony (even an orbital one) you provide a future for the people sent. And after all, an ideal round trip mission would imply society will have changed radically in the (150-175?) years of your trip. Think back 150 years in history; what do you have in common with those people?
  • Proto-Earth - If your planet is like Earth near the beginning of life on Earth, there's Centuries to millennia before the planet will look like Earth even with terraforming. Given the "short" distance of the voyage, you would be better off assessing the needs of Terraforming (which industrial devices, bacteria, etc.) and sending new ships with the appropriate equipment to start the work. Meanwhile, your colonists have to sit around for a century waiting for the arrival of the needed equipment. The other mentioned points still apply, and people may still want to colonize. Just don't plan on sipping margaritas on the beach in anyone's lifetime.
  • Staking claim - If your trillionaires are taking the long view, then establishing a colony means they may come to own the whole planet. Other people may take a dim view of this, and there would be lots of opportunities for good drama. If they have the money to finance the whole thing, they can get away with this, but most governments aren't going to be good at THIS level of mass-giveaway without some accountability (like nationalist sentiment). Rival governments may plan followup missions with the intent of challenging the claims, or sending smaller but faster ships to get there first. Small fast ships may not be good for colonists, and slower, larger missions may be better at staking a legitimate claim to the planet. In this scenario, I'd bring some military hardware and military-trained colonists. I'd also send the family members of the trillionaires, because the descendants of the colonists may not turn over the keys when the second wave arrives...

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