The successful completion of the spacewalk has made the construction plan of the space station a big step forward.

This is also the most important content of this space mission.

The seventh day of the Shenzhou spacecraft in space.

The space vegetables in the orbital module laboratory have grown to a height of nearly five centimeters.

Based on the experience of agriculture above the ground, this has reached the standard of harvesting.

"The finished product in the metal crystal growth furnace is packed."

Nie Haisheng lightly packed the finished product of the experiment into the cargo box and fixed it in the cabin of the return capsule.

These hard-won and costly experimental products will be returned to the earth with them in the return capsule.

"How's the space vegetables packed?"

Compared with solid metal products, vegetables are more difficult to pack.

Because these little ones are more vulnerable.

In addition to the fast-growing greens, there are also some seeds that are very valuable.

The seeds of endangered plants from Sanqing Mountain have also been cultivated and germinated in space.

They now have to carefully pack these very weak little ones into small boxes according to the training they have received before.

It is then padded with cushioning cotton and then stuffed into the cargo compartment of the return capsule.

After packing all the cargo, the two of them did a final inspection of the various systems in the spaceship.

Especially critical energy systems.

The solar wings are working very efficiently and are still working tirelessly.

It will ensure that the equipment on board the spacecraft will be able to operate even after the astronauts are gone.

After all the work was done, the two of them finished their last meal in space.

Pre-prepared food, there is still quite a bit leftover.

In addition to the usual staple foods and dishes, there are actually freeze-dried products of various desserts and fruits.

"Let's take a picture as a souvenir!" Fei Junlong said after completing a series of tasks.

There is still a little bit of free time until the time of their return.

The two of them then used the cameras in the spaceship to take an extremely beautiful picture with the blue earth in the porthole as the background.

After the filming is completed, it is transmitted back to Earth through a relay satellite other than the spacecraft.

It also let everyone on the ground see their joy.

The accompanying relay satellites use the latest communication technology.

The amount of data that will be transferred synchronously has been increased by an order of magnitude.

The most intuitive feeling is that now the ground command center can even have a real-time video connection with the two people in the spacecraft.

Previously, communication between heaven and earth had to be carried out with the help of communication satellites, although video calls were also possible.

But before the call, coordinating a low-orbit communications satellite is not only time-consuming, labor-intensive, but also cumbersome.

Nowadays, they can be seen from above the ground through the cameras in the cabin at any time.

It is also possible to communicate in real time, and the efficiency is much higher than before.

Of course, limited by the current state of the art, it is not possible to achieve high-resolution real-time video.

The resolution can only barely reach 1080p, not that the resolution of the camera cannot be reached, but that the communication transmission speed cannot be reached.

Adding the resolution to the top increases the requirements for transmission speed.

In fact, this problem can also be solved by coordinating several low-orbit communication satellites.

However, everyone has always believed that the current resolution is also acceptable, so don't waste manpower and material resources to do this.

The two astronauts, having completed their last mission in space, closed the door of the re-entry capsule.

He sat quietly on the seat of the return capsule.

Compared with the first space mission, the cushioning mechanism has been greatly improved.

Let the astronauts no longer bear such a big impact force in the stage of violent deceleration.

After reaching the scheduled return time, and after obtaining approval from the ground command center, the two disconnected from the spacecraft in accordance with the operations they had learned during training.

The attitude adjustment engine on the return capsule officially began to work.

The angle was fine-tuned again and again so that the re-entry capsule could be aimed at the re-entry site.

In a short period of time, the re-entry capsule rushed into the atmosphere at an extremely high speed.

The material on the outer wall of the return cabin takes away a lot of heat in the violent friction, protecting the safety of the personnel in the cabin.

The material sublimates and vaporizes to create a thick layer of high-temperature plasma on the surface of the re-entry capsule.

So much so that electromagnetic waves cannot penetrate these plasmas.

The return capsule began to experience the most terrifying black barrier area of the entire process.

Disconnected from the ground.

At this stage, because only the breathing and heartbeat of the two people in the cabin can be heard, the psychological requirements for the astronauts are extremely great.

No amount of training on the ground can hardly counteract such an inexplicable horror.

Fortunately, the two were also able to ease their inner emotions by chatting with each other.

The speed of the return capsule is extremely fast, even higher than that of many missiles.

The black barrier area only took a few minutes.

At this time, the return capsule had already reached the northwest sky, not far from the scheduled Amugulang grassland.

The large electric scanning radar on the ground has been turned on and is ready to find the figure of the return capsule.

The helicopter brigade also began to start its engines, and the iron wings spun and began to step into the grassland.

The convoy set off early and entered the grassland.

Six minutes later, the main canopy of the re-entry capsule opened, and the huge parachute instantly bloomed in the sky.

The speed of the re-entry capsule also followed.

Astronauts sitting inside, even with the cushioning of the cushioning seats, can feel the strong impact.

But fortunately, the two of them have excellent physical fitness, and the space mission time is only seven or eight days, which is not very long, and it has not had a great impact on the body.

Four minutes later, the re-entry capsule threw an exothermic outsole and moved closer to the ground.

Five minutes later, only a few dozen meters above the ground, after the gamma altimeter detected it, it controlled the ignition of the honeycomb recoil engine, and the speed of the return capsule was finally reduced to a minimum.

The two felt two bumps under their buttocks, and then there was no more movement.

Knowing that he was finally back on the ground, a hanging heart finally relaxed.

Ten minutes later, the first to find them was the helicopter group in the sky.

With the help of the searchers, the opening of the hatch was finally completed.

Fei Junlong was the first to climb out of the return capsule, and then with his help, Nie Haisheng also returned to the capsule and walked out.

As aerospace heroes, after arriving on the ground, they basically don't have to think about too many things.

Someone will take the re-entry capsule and the valuable experimental products inside the capsule with them.

The two were carried on a stretcher, and after a brief greeting to everyone, they were sent to the Aerospace Medical Research Institute for physical examination.

——

At the same time that the astronauts returned to Earth, a material that was not too remarkable was born in the Materials Experiment Center of the Rocket Research Institute.

High-purity gallium nitride, and diodes made from it.

This material is still a laboratory product today.

The world's major laboratories produce a lot of output more or less every year.

Especially since the beginning of the 21st century, everyone has become more and more aware that the development of the third generation of semiconductors must be based on gallium nitride, silicon carbide, zinc oxide, etc.

However, at this time, the technology is not yet mature, although everyone has this understanding, but it is generally believed that this is at least 15 years away from practical application.

In fact, if it weren't for Zhang Xingyang's vigorous promotion.

GaN products, which have great prospects in both military and civilian markets, may not be developed until more than a decade later.

In later generations, gallium nitride was widely used in phased array radars.

China has the world's largest output of gallium nitride, with an annual output of nearly 600 tons, close to 90% of the world's production capacity!

This is also one of the important factors why even agricultural UAVs in China were able to use phased array radar at that time.

Without him, only measurable!

This is also the reason why, after the country introduced gallium nitride export restrictions, everyone thought that it would have a significant impact on the foreign radar industry.

Speaking of now, Zhang Xingyang's gallium nitride is extremely pure, and it will become an excellent raw material for radar products.

However, Zhang Xingyang attaches more importance to another point.

Compared with the commonly used silicon semiconductors, gallium nitride itself has considerable physical performance advantages.

For example, large bandgap width, high breakdown electric field, high saturated electron drift velocity, high thermal conductivity, high radiation resistance, etc.

In the future, it will be widely used in various inverters, DC/DC converters, etc.

In particular, the gallium nitride diode that Zhang Xingyang has just developed is the leader of the converter.

After the completion of the research and development of gallium nitride diodes, Zhang Xingyang completed the research and development of DC-RF and RF-DC converters at a very fast speed.

DC-RF, i.e. Current-to-Microwave Conversion.

A microwave generator unit converts the current into microwaves.

RF-DC, on the other hand, converts microwaves into electric current.

This thing may not look good, but it involves the transformation of the energy industry in the future.

Microwave power transmission!

Or with Zhang Xingyang's more familiar name, "Space Three Gorges"!

The concept of microwave power transmission is actually not new, and it has been proposed as early as when people discovered the characteristics of microwaves.

Microwave transmission also has many advantages.

First of all, compared with traditional wire transmission, its loss rate is relatively low, and there is almost no loss in space.

Even in the atmosphere, there are less than five percent of the losses.

Secondly, it is not limited by the terrain, and the terrain factor can be ignored between the power station and the electricity consumer.

This point, even if it cannot be applied on a large scale, is also very useful in emergency rescue, post-disaster relief and so on.

Previously, there were two main technical problems in front of everyone.

One is the efficiency and power of converting current into microwaves, which were relatively low due to the limitations of the semiconductor industry.

It is difficult to meet the needs of high-power conversion, and the conversion efficiency is relatively low, and a lot of energy is consumed in the conversion process.

The physical properties of gallium nitride can solve this problem well, not only can withstand large power, but also the conversion efficiency has been greatly improved.

Zhang Xingyang placed DC-RF converters and RF-DC converters between the experimental sites about 15 meters wide.

At one end is a generator and the other is an electric motor.

It is used to verify whether the work efficiency of this system can meet the requirements.

"Xingyang, can this really succeed?"

Even though Zhang Xingyang has repeatedly created technological miracles before, Geng Bo still maintains a skeptical attitude.

Because this seems to be a bit beyond everyone's imagination, the so-called wireless power transmission on the market before this is actually mostly the application of electromagnetic induction.

That is, in later generations, most mobile phones were charged wirelessly.

This kind of wireless power transmission, although it is free from the shackles of wires, is of little use, because the wireless distance is too small, and it can only take effect when it is close to it.

In life scenarios, there are not many application scenarios, let alone industrial production.

And microwave transmission can really get rid of this limitation!

Although the equipment seems to be small now, in industrial production, it is already very small.

"The success of the experiment is certain, and the main question is how much transformation efficiency can be achieved."

Zhang Xingyang started the generator at one end while answering Geng Bo's question.

The DC-RF converter quickly converts the electrical energy into microwaves, which are then transmitted to the RF-DC converter at a specific frequency 15 meters away.

In the midst of this, the microwave is converted into an electric current, which drives the operation of the motor.

The power of the electric motor is quickly displayed on the display, combined with the generator on the other side.

It is easy for everyone to get the efficiency of microwave transmission.

Thirty-two percent!

This efficiency can be said to be far beyond everyone's imagination.

This energy utilization rate can be said to be very high.

Zhang Xingyang looked at the data on the display screen and smiled:

"We can solve a big energy problem in the future!"

The people present have been working in the space system for a long time, and of course they know what he means.

This is an idea that was put forward in the last century.

Large-scale solar power plants are built in space to generate electricity and transmit this energy to the ground through microwaves.

Cities with huge electricity consumption on the ground can relieve a lot of pressure.

Especially in the summer when the demand for electricity is strong, it can solve the problem of electricity difficulty in many megacities of tens of millions.

Of course, the benefits of microwave transmission don't stop there.

With microwave power transmission, drones equipped with RF-DC converters can cruise in the sky almost 24 hours a day.

There is no longer a need to stop for charging, and in just a few days, the internal wearing parts need to be replaced.

UAV swarm tactics also ushered in an opportunity for real development after this! (End of chapter)