How to make a good landing pad for a start-up colony

Question

Due to the expansion of humanity into the stars, landing pads have popped up on every planet with even a remote resemblance of a permanent human presence, whether they start with a dozen or a thousand people.

For this question, we'll look at the colony starting with a dozen people, these are small, simplistic towns or bases that are either inhabited by desperate refugees, scientists, or prospectors and are expected to grow in population. these are called startup colonies.

My question is, what would make a good dock for a startup colony?

looking for info on how to build a cheap landing pad for a landing spacecraft that can withstand a weight load of (at most) 250 tons and could be built by a small team of colonists, what materials it could be made out of, and what would it need to keep ground personnel safe.

• Most spacecraft that are capable of landing on a planet are single-stage-to-orbit craft or have a booster stage to get back up into orbit.
• capable of loading and unloading freight and passengers
• made of materials that can be easily brought down on first landing or with materials found readily available on most terrestrial planets (metals such as Iron and Aluminum, ceramics, carbon compounds, etc.) or just standard junk
• easy to build by a small, non-specialized team of 15-45 individuals
• Startup colonies are typically established on earth-like habitable worlds with atmospheres comparable to our own, purely to cut down on the cost of life support systems
• the first landers are typically 10-ton SpaceX Starship-like landers (when fully loaded) or, in rare cases, VTOL spaceplanes that do the same job; they don't carry a lot of cargo or crew and can land on any surface that's flat and solid
• Landers that do need landing pads are heavy, carrying 100+ tons of cargo in and out of atmospheres and large amounts of passengers, they only have enough fuel tank volume for a single trip to surface per trip (this limitation is a scheme put in place by interstellar shipping companies and spacecraft manufacturers to motivate colonists to construct fuel depots and refineries and to save on cost, refueled on the surface by colony and by mothership in orbit)
• Certain lander variants also have a booster stage for high-gravity worlds (celestial objects with a surface gravity 1.1g or higher)

These requirements are extremely flexible

Answer 1

I was thinking about this situation for a world I was constructing (pun fully intended), so I'll outline my variation.

This is assuming they are landing on an earth-like world that is human habitable.

A few weeks out from arrival, the Colony Transport releases probes to the planet. Capable of higher deceleration than the Colony Transport, they can coast until much closer and then suddenly decelerate. These probes first do orbital scans, and then descent into the atmosphere at likely landing sites and do detailed geological analysis.

When the Colony Transport enters orbit, they can pick the colony site or chose to deploy more probes. They want a colony site at a river delta where there are several square kilometers of flat land near an ocean, but the mountains aren't too distant, nor is the sea (or a really big lake). The land should be not be swampy, and there should be clay as a nearby material.

Then the Colony Transport deploys two of it's (minimum) three shuttles. The shuttles are weird vehicles. They are capable of water landing, but also possess an undercarriage. They will land on water, but ascend from land. They have both air-breathing jets and rockets. They are a hybrid between the Space shuttle, a jet passenger plane, and a large seaplane from the 1940's.

Two shuttles depart from the ship in orbit. They both carry ~20 people, and have identical payloads. Notable supplies include:

• A hydroturbine or a nuclear reactor
• A backhoe excavator, tipper truck and some sort of compactor.
• An electrolysis/fuel manufacturing plant.
• A small (eg inflatable) boat with an oversize engine. It's a mini tug boat.

Then, early one morning when the sea is calm and the weather is good, the two shuttles water-land in the ocean, and deploy the small inflatable boats. They are then towed up into the river mouth to the colony site. The excavator is unloaded and construction starts on several things:

1. a quarry and clay mine
2. a dock + a haul-out for the shuttles
3. a fuelling station (eg electrolysis + hydrodam)
4. a runway for the shuttles

The surfaces of these facilities are constructed from clay. Yes, it will degrade when wet, but it is a lot easier to obtain than cement. The shuttles are moored in the river until they can be hauled out and inspected.

Now that we have /some/ ground side facilities (and a boat), the Colony Transport can begin to drop some cargo drop pods into the ocean where they can be retrieved by boat. These can contain food supplies, vehicles etc. Anything impact rated! Potentially humans could also be dropped I suppose, but they may not be happy about it. Empty cargo pods are converted into buildings.

When the runway is constructed and dried, and sufficient fuel reserves are available, the shuttles ascend to orbit - taking off using air-breathing jets before switching over to rockets at high altitude. The shuttles do not have to be capable of entering orbit themselves. So long as they clear the atmosphere they can be met in space by 'second stage shuttles' which can transfer loads or boost them. Bonus points if you can coordinate a space-tether with your (orbital) Colony Transport from a sub-orbital shuttle!

From there things can proceed as outlined in JBH's excellent answer.

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So why water-landing shuttles?

Back when airports didn't exist... seaplanes were popular because they could take-off/land anywhere. Then as we build airports, seaplanes became redundant. The same applies here: On a world without infrastructure at least you have the ocean.

Bear in mind we are also doing the opposite of most rocket launches here: we are landing with hundreds of tonnes of equipment - and ascending empty. So by going water landing we can avoid the need for building a huge structural runway that needs to withstand massive braking/impact onto it's surface. The ocean doesn't wear out.... Similarly, a jet-assisted take-off means a rolling launch, again dropping the required ground-side infrastructure compared to a vertical takeoff. Will a clay runway last forever? Nope, but it will hopefully last until a cement plant can be constructed and a concrete one built.

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Also worth considering is that down is easier than up. So while boosting a 100 million tonne Colony Transport into orbit is a feat in the extreme, de-orbiting one is not! Gently landing an arcology from orbit will be hard but it is at least possible, and in this case you can just land the entire colony and forget about space for the next 20 years until your industry is up to it.

Answer 2

Unless you really need the detail, let's simplify this a bit

In the end, you should simplify this a lot. You'll see why as we walk through my "simplification."

To begin, if you read this article about building NASA's Pad #39, which is a serious simplification for the public, you'll quickly realize that addressing the problem a pad with any realism is probably way, way, way beyond what you want.

Worse, there's a difference between landing with parachutes in the ocean and landing on wheels like the Shuttle. Or maybe you have ships that land like a Harrier jet or use some form of gravitics to gently land. Let's not get distracted. Your ships look like bigger versions of the Space Shuttle.

Worse still, then there's launch. And it's pretty rare that the launch requirements and landing requirements line up.

So, unless your ships can't land in the proverbial field like your average Cessna propeller aircraft can, then there is a minimum colony population for the size of pad needed and it won't be twelve people. The investment in launch and landing facilities is a big honking deal. (I'm a fan of reminding people that you really can't ignore economics when worldbuilding.)

So, you need:

• A landing strip capable of dealing with the incoming velocity of the landing craft and its mass.

• A launch pad capable of dealing with the weight of the entire launch assembly and the force of lift-off.

Simple... we need to keep this simple...

It doesn't make sense to haul all the materials to build these to a new planet when the new planet is sitting there with all the materials you need. Especially when the colonists will continue to benefit from the infrastructure you put into place to make this happen. So, what do you need?

1. Gravel pit
2. Cement factory
3. Iron ore mine
4. Smelting and refining
5. Equipment... lots and lots of equipment and the ability to fuel it and maintain it.
6. Transportation (see #5)
7. People. Thousands if not tens of thousands of people.

Granted, the construction crew might leave to build the next planet's transportation hub, but if you think about it, that doesn't make sense. Your colony will need pretty much everyone involved.

If you want to worry about detail...

8. Housing & Recreation
9. Food, water, and sewer
10. Medical
11. Administration
12. Law enforcement
13. Quality/code enforcement

But let's ignore all that. We'll stick with just 1-7.

You can build the landing strip and the launch pad separately. In fact, it might make sense to have two landing strips separated by a considerable distance just in case the weather makes using one too problematic. Trade ships have schedules and they won't always be capable of waiting for the storm to pass.

You might also want to consider building both facilities near large rivers or oceans to include naval ports and land-based terminals so that goods can be delivered to and from the landing and launch areas. Your colony might not need them much right now, but they will need them later.

You know, that Harrier-style space ship that needs little more than a big square of reinforced concrete is starting to look really good.

The length of your landing strip depends on the mass and velocity of your incoming craft. As mass and velocity increase, the length of the landing strip increases. Note that you will need a way to get the landed craft over to the launch area and have the ability to manufacture rocket fuel and boosters, with means either recovering boosters left in space or building new boosters over and over. Now we need:

14. Bauxite mining
15. Bauxite processing to get aluminum
16. Chemical processing
17. Oxygen/hydrogen condensation
18. Manufacturing facilities
19. People, people, people....

Man, I'm really digging the Harrier-style space craft. Remember, this is the simple explanation.

Your launch pad will be deep. that's because you need to vent the launch exhaust. Unless your rockets can be tipped-up into place and stand on their own, they'll need a gantry system that allows for maintenance and crew/passenger access up until launch. You'll also need methods for preparing, moving, and storing goods and supplies for transport on the ship.

20. Rocket assembly area
21. Goods distribution area
22. Some pretty big machines.
23. People... people... people...

Recommendation

In a future where colonization becomes so routine that the idea that only a dozen people can colonize a planet (oh, the legal wrangling that would incur!) you need to develop space craft that don't need landing strips or launch pads. If you insist on either or both, you won't have colonies with just a dozen people, because even after manufacturing is done, you still need to maintain those facilities and you're getting fuel from somewhere (the cost if importing it vs. the cost of manufacturing it...).

Think about introducing Harrier-style orbit-to-planet transports in your world. That way the big ships don't need to land. Even if everything they're carrying is destined for one location, that simply means multiple trips with the I-can-land-anywhere Harrier-style shuttles. And it frees the big ships to haul goods for multiple locations (economics!).

With that being said, all you're really looking for is a sandy or small-gravel rocky area that can be smoothed out and used until frequency of use (due to population increase) demands something more durable and more forgiving to forklifts.

Answer 3

If water's locally available and the ambient temperatures are suitable: pykrete, or some variation. The construction could essentially be a giant water mattress filled with reinforcing fibers, rolled out on a prepared patch of ground, anchored, and filled with water. With appropriate choice of reinforcing fibers, you won't have to worry about debris being thrown from the pad, anything that comes loose will vaporize in the rocket plume.

This won't be particularly permanent, though you could probably refurbish it for multiple uses in quick succession easily enough. Perhaps water-cooled steel would be a better long-term solution, or an elevated platform that allows the exhaust to expand and cool before hitting anything, or a catch tower or cable arrangement.

Answer 4

Land an asteroid.

https://en.wikipedia.org/wiki/Chondrite

They are available in space, for free! They are solid. They come in all sizes. The asteroid will come down to the planet by itself with some encouragement. You can have little rocket droids to steer it. You can let it fall the last few kilometers once you have it lined up, so it gets itself solidly in the ground. Once it is down you can cut off a slice so there is a nice flat face to land rockets on.

Answer 5

A lot of this depends on the planet's surface gravity. A structure that can act as a landing pad for a craft that weighs 250 tons on Earth is much different than a structure designed to handle the same mass on the Moon, where it only weighs ~41 tons.

Given that Earth has the highest surface gravity of any solid object in the solar system, whatever can handle a 250 ton spacecraft on Earth will be more than robust enough to handle that same craft anywhere else.

So just use concrete made from local regolith, with water for noise, fire, and dust suppression.