This is the second part of a series of questions I'll ask about a self-sustaining colonization ship. I'll keep editing this post as things unfold.

If you can, check out the other questions of this series for a bigger picture:

Part I - Construction

Some Context

Each Colonist journey is a one way trip to a new world. There aren't resources or space enough for another 20~200 year trip back, so the people in the ship (about 100 tripulants) must be equipped with whatever they might need to start a new civilization from the ground up.

The original idea is that these giant vessels are not meant to come back home, they're meant to BE home. And this is the main point of this question, since every Colonist must take the passengers to the new world AND serve as a first base of operations to aid them in the creation of a new colony.

Once the Colonist reaches its destination, it will enter the planet and make a landing - after a geological survey to find the best landing place possible, they set the coordinates and start to descend into their new home.

However, this ship is massive and I have doubts about how feasible it is for this landing to take place.

The Question

Taking into consideration the massive ship discussed in Part I, I'd like to know:

Is it possible for this ship to safely make this landing?

Things to consider for this question:

• The destination planet is exactly like Earth except unpopulated;


• The geological survey is but a BS excuse. I'm basically saying they'll ALWAYS find the perfect landing zone;


• Safely means no casualties among the tripulation - but the ship and the cargo can be damaged during the descent;


• The world can't be damaged enough to become uninhabitable (this is here because I've been told that a large enough body might actually burn the world's atmosphere - which is something that a terraforming crew obviously does not want);

I think it is possible. Considering that the initial period after landing will be the most harsh, having to rely only on carried along resources, I would opt for the strategy of:

• While carrying out the survey, park the ship in orbit around the planet


• Disassemble the ship into smaller modules, each equipped with heat shield and parachute, and fit it as a self standing building.


• Land each module independently

In this way a problem during a landing procedure will compromise only a fraction of the total set of structures, and, even accounting for different landing locations, it will be easier to move a small module than a large ship, should it be needed.

Plan to land only what you need

Much of the colony ship has no reason to land.

• The stardrive and its fuel tanks


• Maneuvering thrusters and their fuel tanks


• The shielding


• Command and Engineering


• Air recycling (you might want water and waste recycling)

The list probably goes on for some considerable time. There'll be large amounts of empty space formerly taken up by stores for the journey that's just not needed any more. All of this extra mass and volume would need to be shielded for re-entry greatly increasing the amount of mass unnecessarily being hauled across space. So plan to leave it all in orbit and only take what you need. The rest of the ship can stay in orbit as your first communications satellite.

Eggs and baskets

Don't keep all of the former in one of the latter.

While you're sending three ships, entering an atmosphere is a very high risk activity, the fewer of your eggs you have in each basket the safer you're going to be. Break required parts of the ship down into separate re-entry modules, no more than one critical element in each pod. Make sure you don't lose too much if any one pod is lost.

Why land at all?

You and I live on a planet. That's what we are used to.

But these colonists have lived for decades (centuries) in a finely-tuned space habitat. It seems temporary to us...but for them the habitat is 'home'.

They are in space, near a new star (source of energy), with plenty of asteroids and moons and comets at hand (resources). Everything they need to build new orbital habitats and maintain the life they are used to.

Some adventurous folks and scientists are likely to climb down the gravity well to the attractive earth-like planet. There might even be some outposts down there for various reasons. But civilization and the bulk of the population will be space-based, just like their ancestors.

In theory, yes it can.
But bringing such a giant ship in the athmosphere comes with some problems.

First you have to keep it from breaking apart. Usually the descend comes with lots of vibrations which might break the ship apart.

The next problem you might encounter is the giant heat shield such a big ship would need. (Also I don't know how much a descend like that would heat up the athmosphere)

So you could disassemble the ship in orbit and land small parts of it (I guess that is the way such an undertaking would actually be done) or

If your ship has plenty of fuel or whatever powersource it uses to power its engines and if the engines are strong enough, you could simply slow down the descend to a speed where the heating is no big deal. If you descend slow enough none of the problems would appear.

Using the athmosphere as a break is only done to save fuel. If you have plenty, then you don't need to do that.

This started as a comment on L.Dutchs answer

Bizzarely i actually built a similar ship to what you are referring to in Kerbal Space Program a year or so ago... i wouldn't recommend doing this as i had about 8 fps when leaving Kerbin Orbit... it took awhile.

You need to build you ship modularly with all the components you'd want to have on the landed colony. and then each module can be landed seperately, whether that be with parachutes and heat shields. You do this is for several reasons

1. Redundency: if there is a failure to land a module, that's all you lose


2. Efficiency, different modules will require different locations, you'll want water so being near a water source is required, but the best location to mine for metals extra might be miles away from the nearest water source, so being able to land the different modules in their different ideal locations and not have to move them later is a huge efficiency boost

So you could easily have an Ikea home flat packed with a descent module that would build the areas of housing, which would have the required modules positioned nearby, whereas the mining systems etc can be landed where those required materials are highest.

Once all the habitation and systems modules are landed, what about the rest of the ship... well there is a lot of valuable materials on board that ship, so landing them allows them to be recovered. There's no benefit to leaving it in orbit as its orbit will eventually degrade and reenter the atmosphere possible onto the colony... not ideal... and maintaining orbit will be costly in terms of remaining resources left on board. and that colony will not leave the planet to venture further for another world for a serious amount of time, by which time the systems would likely have degraded to beyond usefulness.

And don't forget that as you approach the planet you'll want to launch several satellites, for GPS, Weather and Communications.

You usually do not want to land large ships because it takes very large amount of energy to get them back to space, but if your ship is designed as a one way vehicle that's then to be used as habitat and will never fly again, then landing is not a problem.

There are a few things to consider though:
1. To slow down a massive ship like that enough to do an orbit insertion, you'll need massive amounts of energy / propellan . Assuming your ship has traveled to another star, at I'm guessing some significant fraction of the speed of light, we can safely assume you can hand wave this away.
2. You might want to look into using a skip-reentry (with multiple skips) instead of more traditional aerodynamic braking to reduce the high heating loads.

https://en.wikipedia.org/wiki/Boost-glide