Chapter 1102 Space-Based Digital Image Transmission System

October 16, 2003, 6:23.

The Shenzhou V return capsule landed smoothly in the scheduled return area in the central part of Meng Province.

It is only 4.8 kilometers away from the scheduled landing center.

This number is considered to be quite satisfactory in the scheduled plan.

It is not even the best result in all the recovery.

However, with the previous two accidents in the United States and Russia as "beautiful examples", the normality of Shenzhou V seems not so normal...

The helicopter No. 736, which is responsible for the search and rescue mission, that is, the helicopter that Chang Haonan took before, quickly landed near the return capsule. The medical team and the search and rescue team quickly approached to help the astronauts open the hatch and conduct the first medical examination in the cabin.

27 minutes later, the first Chinese astronaut completed the exit of the cabin independently and confirmed that all 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 several years or even more than ten years, the emotions that erupted at this moment are not what cheering and celebration can express.

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

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

Some older comrades had red eyes, but they only tried not to show it because of the cameras set up around them.

Originally, Shen Junrong was probably included in this.

But he was diverted by Chang Haonan just now. After confirming that there was no problem 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 couldn't get rid of this idea in his mind.

Chang Haonan was also clapping along at this time. He was called by Shen Junrong twice before he heard someone calling his name, so he turned around quickly.

"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 used this structure inside the fairing, which led to a successful launch but the payload was damaged..."

Contrary to many people's intuition, in fluid dynamics, the shape with the lowest resistance is a round blunt head, which is the bulbous bow of an ocean-going ship or the shape of a manned spacecraft reentry capsule.

A pointed cone will increase resistance.

"This..."

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

It can't even be called an idea.

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

So, I really didn't seriously consider the problem raised by Shen Junrong.

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 technologies such as active cooling."

"As for space utilization..."

At this point, Chang Haonan was still stuck.

In fact, the reason why he thought of the communication problem in the black barrier area has nothing to do with the spacecraft-

Manned spaceflight has been going on for so many years, and the problem of disconnection in the black barrier area for a few minutes is actually not a big deal.

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

And the warhead of a ballistic missile does not really care about space utilization.

The altitude range of 35-80km is exactly the most critical stage for terminal attitude adjustment.

Above 80km, the adjustment accuracy is insufficient.

And the friction during the reentry process itself will cause a certain degree of orbital deviation.

And below 35km...

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

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

There is 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.

So 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 whole process, if the circular error probability can be 50 meters, it is already a hero among heroes.

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

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

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

For example, large ships, or important convoys.

But these ideas are obviously not convenient to disclose to Shen Junrong.

Fortunately, he does not have only this idea to reduce or eliminate the impact of black barriers.

Therefore, the topic was quickly changed:

"The pointed cone is just an example. In reality, a more complex shape can be used..."

"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, these require 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, it was a long time before Shen Junrong spoke again.

He turned back with some curiosity, only to find that the other person was holding a notebook and writing furiously.

Of course, at this time when everyone was paying attention, the "unprofessional" communication between the two did not last too long.

The media, who had been waiting for two days to finally get the opportunity to interview, 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 over from all sides...

...

A few hours later.

NASA headquarters.

Malville strode into the director's office and came to Sean O'Keefe.

He was holding a document in his hand:

"Director, the reconnaissance results from the Central Command have been sent back, and this is the analysis result."

He said, he opened the document and put it on the desk:

"But..."

Before he finished speaking, O'Keefe took over the conversation:

"But no abnormalities 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 content of the report.

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

After the Global Hawk returned, the intelligence was uploaded to China at almost the fastest speed, and then NASA analysts carried out technical processing.

No additional process was involved in the middle.

"Ah..."

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

"Take a look."

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

Of course, the original was also attached.

In Chinese.

The top line reads--

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

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

The text is not long, but the content is very heavy.

It means that we have introduced a set of new technologies, which allows the spacecraft to directly transmit data with the Beijing Aerospace Command and Control Center for about one-third of the time during orbital operation, greatly improving the effectiveness of the spacecraft during its in-orbit period.

They directly send signals to Beijing, and you perform passive reconnaissance missions in Central Asia.

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

"They... just reported it directly?"

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

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

At least not so quickly.

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

"This news is not for their own people, but for us... or, for other countries that have the intention of cooperation..."