Although the space station is built one cabin at a time, I think building it is as simple as "building building blocks".

Actually, it is not the case.

Even the "small" space stations in the International Space Station and the Fanxing Space Station are not simply "building blocks". They involve all aspects of calculation and design, let alone the huge "kilometer-level" spacecraft.

The "100-meter-level" International Space Station has nearly 1,000 cubic meters of pressurized space, and even the "100-meter-level" spacecraft adopts the fool-style superposition method and has nearly 10,000 cubic meters of pressurized space.

The mass of the International Space Station is more than 400 tons multiplied by ten is more than 4000 tons.

The actual situation may be even bigger. For example, if you multiply ten, it will be a pressurized space of 100,000 cubic meters and a mass of more than 40,000 tons.

The International Space Station is already a spot of light visible to humans with naked eyes. Using special camera lenses, you can take relatively clear "pocket" photos without using a telescope. A kilometer-level spacecraft can probably see clear contours directly at the naked eye, and you can even take some details with a camera.

With such a huge structure and such heavy mass, if you want to assemble in space, you have to consider the interaction between the "super-large scale effect" of the structure, the "configuration change effect" and the "space weightless environment".

Once it is not handled properly, an extremely complex "coupling dynamics phenomenon" will occur, which will threaten the safety of the entire spacecraft.

It's not even a simple spacecraft's own safety issue.

If such a big thing disintegrates in orbit, it is likely to have a chain reaction, and then kill 90% of the spacecraft in orbit.

The most important thing is that these debris will form a garbage loop on orbit, which will seriously affect the subsequent space launch mission, and may become garbage and merge into them by accident.

This is the first problem to be solved.

Secondly, it is because the mass and structure are too large, and it is obviously impossible to build through a single rocket launch and orbital deployment. That is to say, the "building building blocks" method used to build the International Space Station and the Starry Space Station before will not work.

To solve this problem, it is necessary to increase revenue and reduce expenditure.

On the one hand, through a "lightweight" design, the quality is reduced while ensuring the strength of the spacecraft as much as possible, thereby reducing the launch cost.

On the other hand, it is about developing new heavy-duty vehicles or new aerospace transportation schemes.

In general, to overcome these two difficulties, we need to further integrate the three research objects in aerospace dynamics, namely orbit, attitude and structure, and then deeply intersect with the control discipline.

Only by doing this step can we lay the theoretical and technical foundation for the construction of "super-large space infrastructure".

How should this kilometer-level spacecraft be designed specifically? That's the design department's business, but the most important thing is... how to transport thousands of tons of materials into space?

At that time, scientists who didn't know what would happen in the next few years thought of several solutions, from low to high technical difficulty, were heavy rockets, space planes, and space elevators.

Heavy rockets, whether it is the construction of the International Space Station or the Star Space Station, they are useful, but even super heavy rockets with a load of more than 100 tons like Saturn V, Long March 9, and SLS rockets are far from enough for a kilometer-level spacecraft.

How to say about aerospace planes, they can be reused and are very convenient to take off and land, but their disadvantage is that they are not capable of carrying capacity.

Although reuse and easy use can make up for the shortage of single-time capacity, the cabin of the aerospace plane cannot be expanded, which seriously limits the size of the space station module.

Just like the size of a rocket's fairing, before the 5-meter-diameter Long March 5 came out, Fanxing's two space laboratories had a diameter of only 3.3 meters. Later, after the Long March 5 rocket appeared, the Fanxing space station with a diameter of more than 4 meters was built.

The Liberty Federation has a super heavy rocket Saturn V with a diameter of 10 meters, so it can launch a Sky Laboratory Space Station with a maximum diameter of 6.7 meters.

The larger the space station, the more test equipment is loaded, and there are more areas for astronauts to move. However, the cargo holds of aerospace planes are naturally not as good as rockets, so using aerospace planes to build a modular space station is definitely not cost-effective, and the space size is absolutely cramped.

If a space station with a kilometer-level size is only 5 meters in diameter, then... it is not difficult to see that it is said for two reasons. I will not discuss the utilization rate. This form is a "rope" in orbit, and the gravity of the earth can definitely disintegrate it.

Unless the space plane just carries materials, then let astronauts weld the huge space station bit by bit in space!

This involves the issue of space construction, which is also a major difficulty.

And the space elevator is interesting.

If heavy rockets and space planes are making breakthroughs in technology in material transportation, then space elevators are just making a fuss about "basic science".

Theoretically, as long as humans can create a very strong "rope", then install counterweights on its tail, stand on the equator and throw them into space.

If the counterweight falls on the geosynchronous orbit, the earth's rotation will straighten the rope like throwing a shot put, and then humans can climb directly into space along the rope.

If humans can climb up, they can naturally climb up with a huge cabin with a diameter of dozens of meters, so that humans will have spacecraft of huge diameters.

Well, theoretically.

The most difficult part is whether you can find a substance with super high strength. If this substance is available, the foundation for building a space ladder will also be available.

In addition, there are still many problems to overcome in the construction of space elevators.

For example, resonance problem.

There is also the most likely fracture problem in synchronous tracks under the action of "stress".

As well as the counterweight blocks that have to be added to reduce "lunar perturbation" and "reduce the risk of space elevators", the transportation cost of this counterweight block is also a problem.

In addition, there are also problems in the site selection of the "ground station" on the ground equator. We must consider issues such as "the annual wind is below level 2", "no cumulonimbus clouds", "monsoon circulation", and even "crack breakage".

If the transportation of raw materials goes well, energy issues must be considered next.

The first one is more mature and reliable, which is solar arrays.

At every moment, the sun will radiate energy evenly along a spherical surface, and humans can use these radiation abilities.

However, humans' technology of using solar energy is still relatively low-level.

Take the International Space Station as an example. In fact, its cabin body is not too large, but in order to ensure its electricity use, it requires huge solar arrays, and even the solar panels in the cabin itself are not enough. Special trusses need to be installed to deploy huge solar panels.

Fanxing's space station has the advantage of latecomer and its solar energy technology has increased, but if it can take photos, its solar panels will definitely be more conspicuous than the cabin body.

Still big.

If such a solar cell array wants to power a kilometer-level spacecraft, the array area must be "overwhelming".

Of course, there is no need for solar arrays, which is to use high-level controlled nuclear fusion.

It just takes "50 years" to develop.

Of course, these are all previous concerns.

The previous super heavy rocket was not cost-effective because it could not be reused and thrown away once. The 10-meter-diameter fairing is too wasteful.

The spacecraft is "not easy to use" because its cargo hold is too small and cannot transport large-sized spacecraft components.

But practical technology can combine these two technologies to create a super heavy rocket that can be reused and add a size to it, which is a super heavy rocket.

That is, the super rocket launch system under development, the giant with a diameter of 20 meters.

It is absolutely invincible to use it to transport parts.

There are also considerations about space elevators, because the material used to make "ropes" is already famous, which is graphene.

However, it takes more effort to build the "rope" needed to build the space elevator, so we simply use super rockets to help the kilometer-level spacecraft plan first.

In addition, the "counterweight" of space elevators on space orbit also needs to be sampled first, and a kilometer-level spacecraft is good.

So there is the now announced plan for spacecraft of kilometer-level announced.

It is said that this kilometer plan is actually phased.

The existing "fifty meters" scale of Fanxing Space Station is still the first phase, and the second phase does not require "copy and paste", but is renamed "Three Hundred Meters".

This "three hundred meters" scale is added to the first phase of "fifty meters".

The first step in the second phase of the plan is to increase the interface of the space station. This step does not use the Super Rockets, and the upgraded version of the reusable Long March 5 is enough.

At that time, a test cabin with spacecraft berthing facilities will be launched. It has a cabin with a diameter of 4 meters, a total length of 16 meters, and a pair of interfaces in the middle part, which can be connected to the "back" of the core compartment and form a "T-shaped" structure with the core compartment.

There are node compartments on both sides of this special test compartment, but this node compartment has only two opposite interfaces for spacecraft to be parked.

For example, the Muquan aerospace plane and the Benyue-class spacecraft.

When they are connected to this node cabin, their cabins are connected, and they are less than 3 meters apart. In addition, the barrier of the living cabin of the Benyue-class spacecraft is only 7 meters, which is much more convenient than before to pass through the entire core cabin to carry things.

With this cabin, the space station can park four spacecraft at the same time.

In addition, the remaining berths in the original core cabin are very flexible.

The reason why the cabin has experimental functions is that it is purely empty and empty. Instead of making a purely expanded parking port, it is better to add some experimental cabinets and do more experiments.

The second step of the second phase of the project will require a super rocket because it needs to transport large items.

That is, the "big circle" of the space station seen by the audience.

It is a foldable rotational simulation gravity compartment, and the diameter can reach 100 meters after being expanded.

The cabin with a large circle is not a ring that penetrates, but four independent arc-shaped cabins of 10 meters long, connected to the central axis by four cylindrical telescopic channels, and then there are alloy tubes of varying lengths to connect them to make it stronger.

This rotary simulated gravity cabin can provide up to 0.4G of simulated gravity, less than half of the Earth's gravity, and is almost the same as the gravity of Mars.

It rotates slowly. Although it can provide higher simulated gravity when it rotates faster, its safety will be reduced, so it can only rotate slowly to provide 0.4G simulated gravity.

However, although the 0.4G simulated gravity is not strong, it is OK for astronauts. At least they can find the feeling of being on Earth, and they can eat, sleep, wash, and go to the toilet slightly, and exercise more efficiently.

And this is much better than the 0.16G gravity of the moon.

This rotation simulates the gravity compartment when transporting, with a folded diameter of 18 meters. Four individual arc-shaped compartment sections can almost form a ring with a broken opening, which can be stuffed into the 20-meter-diameter cargo hold of the Super Rocket.

Its expansion is semi-automatic, the infrastructure can be automatically expanded, and the alloy pipe used for reinforcement requires the astronauts to walk outside the cabin for connection and fixing, which is a considerable project for astronauts wearing thick outer cabin space suits.

There are two such rotary cabins in the second phase of the project, one forward and the other reverse. After the two are fully expanded, they will be opened together.

Next is the "industrial zone" of the second phase of the project, including production and manufacturing modules and maintenance modules. Their common feature is - big!

Their diameter is also 18 meters, but unlike the rotating modules that have many "gaps" folded. They do not expand, and they themselves are large cylinders with a diameter of 18 meters.

It's like a slightly smaller circle of super rocket spacecraft, and it's like a sky and core cabin with many larger circles.

The reason why it is so large is that in addition to the large space required for rail production and manufacturing modules, the maintenance module also requires large space.
To be continued...