Chapter 1102 Space-based Digital Image Transmission System

2003年10月16日，6时23分。

The Shenzhou V return capsule landed successfully in the designated return area in central Mongolia Province.

The scheduled landing center is only 4.8 km away.

This number is considered to be average according to the planned plan.

It is not even the best result in all the recycling history.

But with the previous two accidents in the United States and Russia as a precedent, the normality of Shenzhou V seems not so normal...

Helicopter No. 736, which was responsible for the search and rescue mission and was the same helicopter that Chang Haonan had taken before, quickly landed near the return capsule. The medical team and the search and rescue team quickly approached, helped the astronauts open the hatch, and conducted the first medical examination in the cabin.

27 minutes later, China's first astronaut completed his own spacewalk and confirmed that all his physical indicators were normal...

At this time, the atmosphere in the command and control hall was much calmer than before.

For many people who have been working hard for this for several years or even more than ten years, the emotions that erupt at this moment cannot be expressed by cheers and celebrations.

According to the plan, the commander-in-chief of the manned space program should officially announce at this time that the Shenzhou V mission was a complete success.

But he stood behind the small podium and opened his mouth several times, but he couldn't complete the sentence that he was already familiar with.

Some older comrades even had tears in their eyes, but they tried not to show it because of the cameras set up around them.

Originally, Shen Junrong should most likely be included here.

But his attention had just been diverted by Chang Haonan. After confirming that there were no problems with the return capsule and astronauts of Shenzhou V, he switched back to the previous topic at the speed of light.

"Comrade Haonan?"

Obviously, as an expert in the field of measurement, control and communication, Shen Junrong could not get rid of this idea in his mind.

Chang Haonan was also clapping along at this time. It was only after Shen Junrong called him twice that he heard someone calling his name, so he quickly turned around.

"You just mentioned changing the shape of the reentry body to a pointed cone... but the effective space inside this shape is too low, and more importantly... the high temperature and ablation caused by aerodynamic heating will be more serious. In addition, the structural strength of the thin-shell cone is also problematic... About ten years ago, we had a rocket that was successfully launched but the payload was damaged because this structure was used inside the fairing..."

Contrary to what many people think, in fluid dynamics, the shape with the lowest resistance is a rounded blunt nose, which is the bulbous bow of an ocean-going ship or the shape of a manned spacecraft's return capsule.

A pointed cone will actually increase resistance.

"This……"

In fact, what Chang Haonan just proposed was just an idea at most.

It's not even an idea.

Taking a pointed cone as an example is simply because this shape is easier to calculate, and the result will definitely reduce the thickness of the plasma sheath.

Therefore, I have never really considered the question raised by Shen Junrong seriously.

After some thought, he spoke again:

"High-temperature ablation can be overcome to some extent by increasing the thickness of the heat-resistant coating or by techniques such as active cooling."

"As for space utilization..."

After answering this, Chang Haonan was still stuck.

In fact, the reason why he thought of the communication problem in the black barrier area had little to do with the spacecraft.

After so many years of manned space flight, a few minutes of disconnection in a blackout area is actually not a big problem.

On the contrary, it is very deadly for ballistic missiles.

The warhead of a ballistic missile does not actually care much about space utilization.

The altitude range of 35-80km happens to be the most critical stage of terminal attitude adjustment.

Above 80km, the adjustment accuracy is insufficient.

And the friction during the re-entry process itself will cause a certain degree of orbital deviation.

And below 35km...

There is no such thing as deceleration for ballistic missiles. The maximum tail speed can reach 15-20 times the speed of sound, which is 5-7km per second.

After breaking through the black barrier, it hit the target in a few seconds.

There is simply no time to adjust.

However, due to the existence of black barriers, the warhead can neither passively receive satellite signals nor actively use radar guidance.

Therefore, the accuracy of the hit can only rely on the gyroscope for orbit calculation.

Except for medium- and short-range missiles that do not leave the atmosphere throughout the entire process, if the circular error probability can be 50 meters, it would be a hero among heroes.

And if the warhead can use synthetic aperture radar for terminal guidance...

The 50-meter hit accuracy is basically the lower limit.

More importantly, it can also be used to attack targets during activities.

For example, large ships, or important convoys.

But these ideas were obviously not convenient to reveal to Shen Junrong.

Fortunately, this is not the only idea he has for reducing or eliminating the impact of the black barrier.

So quickly switching topics:

"The pointed cone is just an example. In reality, we can use more complex shapes..."

"In addition, injecting substances into the plasma flow field... such as sulfur hexafluoride, rhenium hexafluoride, or carbon tetrachloride can also effectively reduce the electron density in the plasma sheath. Of course, this requires opening holes in the head and sides of the reentry body, and designing the channel structure, which is also a big challenge for the overall structure..."

After Chang Haonan finished speaking, a long time passed and he didn't hear Shen Junrong speak again.

He turned around curiously, only to find that the other person was holding a notebook and writing furiously.

Of course, at this moment when everyone is paying attention, the "unofficial" communication between the two did not last too long.

The media, who had been waiting for two days to finally get an interview opportunity, swarmed in, and soon someone noticed Chang Haonan and Shen Junrong not far away.

In the blink of an eye, several microphones with different media logos were handed to me from all directions...

……

A few hours later.

NASA Headquarters.

Malville strode into the chief's office and stood before Sean O'Keefe.

I also have a document in my hand:

"Director, the reconnaissance results from the Central Command have been sent back. Here are the results of the analysis."

Then he opened the document and put it on the desk:

"but……"

Before he could finish, O'Keefe took over:

"But no anomalies were found. There was only one S-band signal source, but the communication capacity was extremely low?"

He didn't even look down at the report.

"Well... that's true, but how come you..."

After the Global Hawk returned, the intelligence was uploaded to the country at almost the fastest speed, and then technically processed by NASA analysts.

There is no additional process in between.

"Ugh……"

O'Keefe shook his head helplessly, took out a few sheets of paper from the computer, and handed them to Malville opposite:

"Take a look."

The latter took it and found it was a translated news briefing.

Of course, the original document is also included.

Chinese.

The top line reads:

"my country's first manned space mission was successfully completed, and the space-based digital image transmission system made a contribution"

Although the translation was rather stiff, the title still made Malville's heart skip a beat.

The main text is not long, but the content is very important.

He said that we have introduced a set of new technologies that allow the spacecraft to directly transmit data with the Beijing Aerospace Command and Control Center for about one-third of the time during its orbital operation, greatly improving the spacecraft's work effectiveness while in orbit.

They are sending signals directly to Beijing, and you are performing passive reconnaissance missions in Central Asia.

It would be a miracle if we could get useful information.

"They...just reported it directly like that?"

Malville is also a veteran in NASA and has some understanding of the Chinese style.

Generally speaking, after new technologies are put into use, they will not be announced so bluntly.

At least not this fast.

O'Keefe rested his arms on the table, staring at the report in front of him that had not yet been opened. He was silent for a while before continuing:

"This news is not for them, but for us...or, for other countries that are interested in cooperating..."