Supercomputing centers have devoted a large part of their computing power to calculating the movement of the atmosphere in the mesosphere.

Although the force of convective weather is much weaker than that of the troposphere due to the very low density of the atmosphere in the mesosphere, this does not mean that the atmospheric movement in the mesosphere is negligible.

The mesosphere does not produce high and low pressures, but because the atmosphere in the mesosphere is very dense, long-term fluctuations such as planetary waves are transmitted from the bottom layer with a large amplitude.

According to this wave phenomenon, a mechanically unstable part is formed in places with extremely large amplitudes, and this wave phenomenon also has a great impact on the atmospheric circulation in its vicinity.

If these issues are not taken into account, the use of vacuum pipes in the atmosphere can be very problematic.

Although the plan for the first phase of the mass projector system does not intend to erect a vacuum pipeline in the middle layer, the second stage in the future will definitely be erected.

So these problems have to be considered, since the mass projector system is a system, then the slightest variable, can cause the terrible butterfly effect.

In addition to the problem of atmospheric movement in the mesosphere, there is another problem, the problem of the space station.

In the second phase, Huang Haojie plans to build a space station near the Kármán Line, which is 100 kilometers above sea level and is commonly referred to as ultra-low Earth orbit.

Why do artificial celestial bodies such as artificial satellites or space stations on one side operate at an altitude of more than 300 kilometers above sea level, and generally operate at a position of 500~600 kilometers?

That's because the area at an altitude of 100~300 kilometers above sea level, although it belongs to the aerospace region in the definition of the aerospace industry, is still very high in the atmosphere (relative to outer space).

In this way, the artificial object will inevitably be affected by the air resistance in this area, although this air resistance seems very small, but once the time increases, the height of the artificial object will definitely continue to decrease.

As the altitude of the artificial celestial body continues to fall, it will get closer and closer to the ground, and the closer it is to the ground, the denser the atmosphere will become, which can only produce a vicious circle and finally fall to the ground.

Of course, in this area, not no one has tried to use it, for example, the space agency of the Sun Country, the "Swallow" ultra-low orbit experimental satellite launched last year (2017), the operating altitude of the Swallow satellite is between 180 ~ 250 kilometers.

In order to counteract atmospheric drag, the Sunman uses an ion engine.

This type of engine works by ionizing the gas first, and then using electromagnetic force to accelerate the charged ions and eject them, using the reaction force as the power propulsion.

Ion engines have always been a popular power for the research and development of various aerospace powers, and are known as the main force of future aerospace power, and various aerospace powers are constantly developing them.

The Sunman launched this ultra-low orbit satellite primarily to test the efficiency of the ion engine and the durability of the materials.

However, this swallow satellite weighs only a few tens of kilograms all day with fuel.

The reason why it is so small is mainly because of one of the weaknesses of the ion engine, that is, high specific impulse, low thrust, if you want to achieve high thrust, the only way is to put on the nuclear battery.

Otherwise, Galaxy Technology's Kármán line space station cannot use an ion engine as a vector correction power, after all, in addition to the mass of several hundred tons of space station, it also needs to withstand a cable mass of up to 40 kilometers.

How does a space station with a mass of several hundred tons use ion engines? Unless Huang Haojie points out the nuclear fusion generator now, he still obediently plays with chemical energy propulsion!

However, chemical energy propulsion is not impossible to consider.

There are two types of fuels for chemical propulsion: one is a liquid substance, the other is a solid substance, and there is a liquid-solid mixture.

Liquid fuel: Theoretically, the optimal liquid fuel is liquid hydrogen, which can be mixed with liquid oxygen to produce a specific impulse equal to approximately 350.

Specific impulse is the ratio of the thrust (kgf) of a chemical engine to the mass flow rate per second (kg/s) of the ejected particle.

If you replace liquid oxygen with liquid ozone or liquid fluorine, then the specific impulse can be increased to about 370, and the woolly bear has a hydrofluorine generator, and the problem is that the product of combustion is highly toxic.

Engines in which both the combustor and oxidizer are in liquid form are called liquid fuel engines.

In addition to liquid hydrogen, methanol, ethanol, hydrazine hydrate, dimethylhydrazine, nitromethane and other substances can be used as liquid fuels.

Solid fuels such as sodium borohydride, diisocyanate dipolyrate, ferrocene and its derivatives can be used as composite solid fuels.

Some metals or non-metals with low density, such as lithium, beryllium, magnesium, aluminum, boron, etc., especially beryllium can release huge energy in the process of combustion, and the heat released by complete combustion of each kilogram of beryllium is as high as 15000 kJ, which is a high-quality chemical fuel, and the heat released is more than hydrogen.

These metals are usually made into fuel agents with nano-sized particles.

For example, the addition of nanoscale aluminum or nickel particles with a mass fraction of 1 to the solid fuel propellant launched by a rocket can increase the heat of combustion per gram of fuel by about 1 time.

However, the disadvantages of these fuels are that some of these elements are scarce and all involve technical difficulties when burning – smoking, oxide deposition, and so on.

If among the two fuels, one is solid and the other is liquid, it is called a solid-liquid chemical energy engine or an engine that directly calls its substance name; For example, hydrogen-oxygen engines.

Because the energy produced by the solid combustion agent is higher than the energy emitted by the liquid oxidant, the rocket engine developed is mostly a solid-liquid rocket engine, and the two fuels meet and burn to form a high-temperature and high-pressure gas, and the gas is ejected from the nozzle, generating a huge thrust and sending the launch vehicle into space.

Huang Haojie thought about this question, and suddenly he reacted: "Maybe that thing can be used." ”

He immediately pulled up the [Hydrogen Curing Catalyst] database, and thought about it as he calculated.

After being solidified by the hydrogen curing catalyst, the hydrogen will show a metallic hydrogen state, but this solidified metallic hydrogen loses the characteristics of superconductivity and explosion at room temperature due to the doping of the catalyst.

It can be said that there are gains and losses, and the Institute of Materials has named this metallic hydrogen substance as submetallic hydrogen.

In general, submetallic hydrogen is very stable, and only when stimulated by certain conditions will the metallic hydrogen state be released and the previously solidified metallic hydrogen will be released.

The density of submetallic hydrogen is about seven times that of liquid hydrogen, of which 94% is hydrogen atoms, and the remaining 6% is a solidification catalyst.

1 cubic meter of submetallic hydrogen can produce 6.58 cubic meters of liquid hydrogen.

We can see the difference between the densities of the three states of hydrogen: 0.089 kg per cubic meter of gaseous hydrogen, 70.8 kg per cubic meter of liquid hydrogen, and 497.2 kg per cubic meter of submetallic hydrogen.

Perhaps the most troublesome of the space rockets is the storage of liquid hydrogen, although the preparation of hydrogen is very simple and can be obtained by direct electrolysis of water.

Liquid hydrogen has minimal space requirements, but it needs to be stored at minus 225 degrees Celsius, which requires a lot of energy to maintain this temperature.

Hydrogen is the smallest gas with molecular weight and is lighter than helium, so it escapes very easily.

Therefore, liquid hydrogen is not easy to store, because this thing is not only flammable and explosive, but also needs to be sealed and stored at low temperatures, even if it is sealed and stored at low temperatures, if it is not used for a long time, liquid hydrogen will slowly leak away.

Submetallic hydrogen successfully solves this problem.

Huang Haojie sat on the chair and looked at the information of submetallic hydrogen, it seems that he wants to cooperate with Dongtang Aerospace System, relying on Galaxy Technology alone, it may be too late.