As the current chief designer of the Long March 3 rocket, Li Hua is well aware of the large and small affairs of the Xichang Satellite Launch Base.
For example, where is the backup power supply for the base?
For example, what is the activation password for the Space Carrier?
For example, how to take the escape route at the base.
Another example...
The specific structure of the foundation groundwater pipeline integration point.
The pipeline integration point he is referring to is located about five meters below the ground. It is mainly used for sewage discharge in the southern buildings of the base... that is, the command building and guest house.
Among them, the underground water pump was installed just last year under his leadership, and it didn't even show the external area map.
In other words...
The measurement results mentioned by Xu Yun are completely consistent with what Li Hua has learned, and it can even be said that there is no deviation at all.
More importantly...
This gravity gradient meter can actually scan cockroaches!
Of course.
The exclamation point in this sentence has nothing to do with Li Hua's hatred of cockroaches, although cockroaches do deserve to die.
What surprised him was that cockroaches were so small that they could be scanned by a gravity gradiometer through a five-meter bottom layer.
To know.
The weight of an adult cockroach is generally between 1-2 grams. If the soil thickness is five meters and the texture is uniform, the gradient change of a cockroach should be...
2.76x10^-12m/s2.
This accuracy value alone has exceeded that of Neon and other countries, and is comparable to the Goce satellite, which has the highest apparent accuracy.
Thinking of this, Li Hua couldn't help but touch his chin.
Could it be...
Can this instrument really pass that test?
But soon, Li Hua dismissed this idea.
His father taught him a saying since he was a child, which is that a man who can walk a hundred miles is half a mile, which means that the closer something is to success, the less you should take it lightly.
Not to mention AC Milan, which has been beaten repeatedly. At the press conference a few days ago, Atsushi Suzuki proved this with his own reputation.
Therefore, Li Hua is very clear that now is not the time to make a final conclusion.
Then he turned his head, waved to Guo Ziyang again, and whispered a few words to him:
"Xiao Guo, go and contact Chef Ma over there in the cafeteria..."
After hearing this, Guo Ziyang nodded quickly:
"receive!"
As he spoke, he took out a communication device specially made by the Xichang base and dialed a number:
"Chef Ma... Well, it's me... Could you please ask Master Cai to drive the car over... Yes, it's the car from 4.2. We are preparing to stand by here..."
After hanging up the phone.
Guo Ziyang returned to Li Hua.
A few more minutes passed.
A 4.2-meter blue-brand cold chain truck drove toward the canteen of the base. The driver was a man in his forties.
Li Hua hailed the car to an area twenty meters away from everyone, and said to Xu Yun at the same time:
"Dr. Xu, this is a material transport vehicle for the base canteen. The vehicle is covered with an anti-shooting net. The material of the vehicle compartment is also made of nano-color tungsten bronze. Please try and see if you can detect the situation inside the vehicle."
Xu Yun:
"....?"
He wanted to ask Li Hua a question in return. Anti-shooting network understands. Are you serious about nano-color tungsten bronze?
However, this kind of complaint only flashed through his mind, and Xu Yun quickly turned his attention to the inspection of the car.
Although the detection target this time is located on the ground, due to the presence of "a stomach", the difficulty is many times higher than the previous pipeline integration point - after all, the pipeline is only five or six meters underground, so it doesn't count.
Go deep.
Then very quickly.
The f-500 central axis drone equipped with a gravity gradiometer came to the sky above the car and began to conduct gradient detection.
Considering that some students still have some doubts about the principle of gravity gradiometer, here is a less rigorous but easy-to-understand example to explain:
Suppose there are various items on your desk, such as a tissue box, a razor that has not been used up, a keyboard, a computer screen, a half-drunk Coke, etc.
The volumes and heights of these items are different.
At this time.
You hold a rope in your hand and start sweeping it from the left to the right of the table - assuming that the rope will undulate along the surface smoothly when it encounters an object.
Then when the rope sweeps these objects, the height between it and the tabletop will fluctuate with the appearance of the object. Compared with the tabletop, this change is the so-called 'gradient difference'.
The gravity gradiometer is equivalent to a 'rope' whose sensitivity has been increased countless times, and can accurately outline the scene minute by minute.
For example, there is a candy box on the table. There are more candies on the left side of the box and less candies on the right side.
Then the gradient difference between these two intervals will be further different. The more sophisticated the gradiometer, the better it can measure this gradient difference.
This kind of measurement is not the same as perspective. You can't see the specific image inside, but it can be analyzed through the difference of the signals. That's why Xu Yun said before that the water pump might be considered a coffin if it was in the wild.
class objects.
In other words...
If this thing is installed on a satellite, it can also detect some information that cannot be detected by satellite remote sensing modules...
Of course.
Again, this example can only be used for understanding, and the theory is not very rigorous.
His eyes returned to reality.
five minutes later.
Zhang Han, who was in charge of statistics, once again walked to Xu Yun with a document:
"Dr. Xu, the results are out."
Xu Yun took the report and looked at the cold chain truck a few times, then rotated the report 90 degrees so that the image was in the same direction as the front of the car.
After doing this, he looked at the results and said to Li Hua:
"Gong Li, according to our inspection, the last thing loaded in the car should be a basket of cabbage."
"Further inside are celery, winter melon, eggplant...and a graph that we haven't entered data into yet. It looks like coriander or garlic sprouts."
"In addition, we also scanned the car's engine, which should be a 3.0L engine. In addition, the car's rear suspension seems to have some cracks... hmm?"
Talking and talking.
Xu Yun was suddenly stunned and stopped talking.
See this situation.
Li Hua on the side couldn't help his eyelids twitching and asked aloud:
"What's going on? Dr. Xu?"
Xu Yun frowned with a complicated expression, scratched his head, pointed at the car and said:
"It's not a serious situation, Mr. Li. According to the measurement of the gravity gradiometer, there seems to be... a cat near the chassis of this car."
Li Hua was stunned for a moment, and his expression suddenly became a little subtle:
"......a cat?"
Xu Yun nodded.
After receiving Xu Yun's affirmative reply, even though Li Hua had rich experience, he was still a little confused at this time.
But soon he forced himself to recover his thoughts, took a deep breath, and said to Guo Ziyang:
"Xiao Guo, ask Master Cai to put out the fire first and take a few people to check the car."
Guo Ziyang took the order again:
"clear!"
After saying that, Guo Ziyang turned around and took a few people to tinker with the car.
The structure of the chassis is as the word implies, located at the bottom of the car.
Therefore, you do not need to open the front engine during inspection, you only need to remove the carriage.
It's a coincidence that...
The tractor Guo Ziyang used when transporting the f-500 central axis drone was right next to everyone. The maximum load-bearing mass of this thing is as high as 2 tons.
The maximum load of the 4.2-meter refrigerated truck is only 1.5 tons, so after a while of work, the truck was unloaded onto the tractor.
As a result, the carriage was just moved away.
A swaying cat tail and a half-striped butt appeared on the side of the chassis, and the short legs were flapping and jumping.
It is clear.
The owner of the tail was frightened by the movement of the carriage and was trying hard to get into the gap in the chassis.
Upon seeing this, Guo Ziyang put on his labor protection gloves, stepped forward and pinched the kitten's back half, and pulled the little guy out with a slight force.
This is a small civet cat the size of a palm, with regular features and a hint of blue film in its eyes.
After falling into Guo Ziyang's hands, he didn't struggle. He kept meowing and yelling, as sharp as an air raid siren:
"giao~giao~"
See this situation.
The eyes of the only women at the scene, Huang Yuting and Zhang Han, instantly flashed with little stars, and they looked as if they were ready to transform into Empress Shiji at any time.
Fortunately, they both still maintained their basic sanity and knew that this was not the right time to suck cats, so they did not take any further action.
Li Hua walked to Guo Ziyang, gently touched the top of the little cat's head with his hand, and said to Xu Yun:
"Dr. Xu, it seems that our test of units on the ground has passed smoothly this time."
Xu Yun nodded with approval.
After the carriage was disassembled, the driver followed Li Hua's instructions and opened the back door of the garage to reveal the interior.
Although they were not far apart, everyone could still clearly see the distribution of ingredients in the garage, which was exactly as Xu Yun said.
The only slight difference was that the pile of things that Xu Yun thought were garlic sprouts or coriander were actually Zheergen, a well-known ingredient in Sichuan and Chongqing. This data was an import problem and had nothing to do with accuracy.
With the distribution of ingredients and the discovery of this little civet flower, the second stage can indeed be regarded as officially passed.
Then Xu Yun thought for a while, resisted the desire to tease the cat, and asked Li Hua:
"Gong Li, what should we test next?"
Li Hua was silent for a moment after hearing this, then turned around and looked at each other with Ge Tongyou, both of them had solemn expressions on their faces.
Li Hua patted Xu Yun's shoulder and said simply:
"Come with me."
After saying that, he waved his hand, and a ten-seater electric car drove up quickly - in some schools, this kind of car is usually called Dabai or Xiaobai.
When Xu Yun saw this, he didn't ask any questions and obediently led everyone into the car.
The control console of the gradiometer was moved onto another trailer. There was nothing else at the Xichang Satellite Launch Base, but there were many vehicles of various sizes.
As for that kitten...
She was still held in Guo Ziyang's arms, and the specific placement would have to be discussed after the measurement was completed.
Then a group of people drove along a road in an electric car for more than ten minutes before stopping at the foot of a mountain peak.
After the operator directs the drone to fly to the sky.
Li Hua pointed to the mountain peak in front of him and said concisely as before:
"Xiao Xu, the highest height of this unnamed mountain is 319 meters. Don't ask for details now. Just explore it along the mountainside."
"We'll talk about it if we get results. If we don't, we'll close the team."
"...."
Xu Yun followed Li Hua's direction and glanced at the mountain peak in front of him, a flash of thought flashed in his eyes.
319-meter peak...
Even halfway up the mountain, the height is about 160 meters.
This height value undoubtedly exceeds the scope of the Yongling Underground Palace.
Even if the Ming Dynasty had abundant military virtues, it would be impossible to build the underground palace containing the "Yongle Dian" 160 meters below the ground - let alone the Ming Dynasty, the Song Dynasty, where 1,100 copies were magically modified, would be quite troublesome.
So it's obvious.
The purpose of Li Hua's test this time is definitely not for civilian use of the gravity gradiometer... That's wrong, the basic performance is that simple.
Or to be more precise...
The will and attention of the initiators of this round of testing are definitely higher than those of Li Hua and Ge Tongyou.
The previous two tests were just small tests, this time is the real one...
Big exam.
Think of this.
Xu Yun no longer hesitated and said to Zhang Han:
"Sister Zhang, just do what Li Gong said, circle the mountain and get results as soon as possible."
Zhang Han obviously realized the seriousness of this test, said yes, and left to make preparations.
At this moment.
within the entire site.
No one spoke a word, only the little raccoon flower, which had regained a little strength, kept meowing in Guo Ziyang's arms.
Two minutes later.
After the equipment debugging was completed, the f-500 central axis drone began to fly around with a gravity gradient meter.
The principle of the gravity gradiometer has been explained with a simple example above, but in fact, the difficulty of operating the gravity gradiometer is much higher than the 'line' in the example.
Theoretically speaking.
Gradient is a special form of Jacobian matrix. When m=1, the Jacobian matrix of the function is the gradient.
This concept was originally set for field theory, and any field can be used to understand gradients.
It was later cited in mathematics to indicate the direction and magnitude of the fastest variable rate of a function at a specified point. It is a digital abstraction of changing efficiency.
It is for this reason.
Gradient calculation in physics involves the numerical solution of partial derivatives of multivariate functions. An input point theoretically has 256x12 contour function values, so its requirements for measuring particles are unimaginably high.
A similar example is buoyancy.
The reason for the existence of buoyancy is that there is a gradient in the liquid pressure in the direction of gravity, which involves the category of hydrostatics.
So let's be honest.
Xu Yun was not sure whether he could detect the internal scene from the 160-meter mountain height.
And just when Xu Yun looked up at the drone in the sky, Zhang Han, who had been paying attention to the scanning situation, suddenly let out a light sigh:
"Hey...Dr. Xu, there are a lot of ice shards on the mountain...it almost covers the entire mountain."
"Ice slag?"
Xu Yun was slightly startled when he heard this.
Suddenly he thought of something and suddenly turned his head to look at Li Hua.
But before Xu Yun could speak, Li Hua gently shook his head:
"Dr. Xu, didn't I tell you not to ask any more questions?"
Xu Yun opened his mouth, but finally fell silent.
When he raised his head again, the expression on his face became much more solemn.
It is now mid-February, and a mountain peak of more than 300 meters may be covered with snow, but it will never be covered with ice slag on a large area - in fact, it is unlikely even in the cold winter, and ice scum should not appear at all.
How about being in the mountains...
So it's obvious.
These ice slag must have been placed artificially.
The purpose of this step... is undoubtedly much more secret than Xu Yun originally thought.
