Chapter 414

It's been mentioned before.

On the far side of the Moon, it is impossible to receive radio wave signals from the Earth.

So at this time, there needs to be a relay star.

In May of this year.

The China National Space Administration launched a relay star to the vicinity of the moon.

The name of the relay star is Magpie Bridge.

The Queqiao relay satellite is the world's first communication satellite operating at the Earth-Moon Lagrange L2 point.

The main job of Queqiao is to be responsible for the communication between the probe and the ground command center when Chang'e-4 is on the far side of the moon.

The signal sent by the probe needs to pass through the transfer station of the Queqiao before it can be accepted by the ground command center.

In this relay, there will naturally be a signal delay.

And Wu Zheng told Gu Lu.

This signal delay is four minutes and thirteen seconds.

That is to say, when the probe is on the far side of the moon, what is shown on the large screen of the command center is actually the position and state it was in four minutes and thirteen seconds ago.

It is impossible to carry out operations and commands!

This is one of the biggest problems the probe encountered during the moon landing!

…………

The time came to 10 a.m. on the 27th.

The Chang'e-4 probe, which orbited around the moon, finally came to the far side of the moon.

The large screen of the command center, the moment the probe arrived over the far side of the moon, the entire screen suddenly went black.

This is a sign of a signal outage.

Everyone in the command center had known that this would happen, so they didn't panic too much, and everyone was still busy at their respective posts.

Four minutes and thirteen seconds later.

The large screen flashed for a moment, and then the picture appeared.

Wu Zheng immediately instructed a member of the project team, "Zhang Min, start recording data and calculate the best location for the moon." ”

"Yes!"

A young man with glasses crackled on the computer in front of him, and his gaze under the glasses was very serious.

The Chang'e-4 probe orbits around the Moon for two hours.

Recording data and calculating the best landing site, coupled with data review, would have allowed the Chang'e-4 probe to pass by the far side of the moon at least twice.

That's four hours.

And also......

The probe also takes distant photographs of the far side of the Moon.

After all, this is the first time that Huaguo's probe has arrived on the far side of the moon, and things like topographic photos of the far side of the moon are still quite important to Huaguo's lunar exploration program!

So, on the Chang'e-4 probe, multiple external cameras were installed.

"Can I help with anything?" For four hours, Gu Lu couldn't stand here, so he asked Wu Zheng if there was anything he needed help with.

"Professor Gu, you and Zhang Min are responsible for calculating the best place for the probe to land on the moon, where and at what angle the von Kármán impact crater landed on the surface of the moon, we must confirm these things one by one!" Wu Zheng found a job for Gu Lu.

Gu Lu nodded in response, "No problem, just leave it to me." ”

Gu Lu pulled over a chair and sat directly next to Zhang Min.

And Zhang Min has no opinion on Wu Zheng's arrangement.

If you have one more person to help, it will save a lot of time when calculating the landing position of the probe.

"Professor Gu, this is some of the data that has been obtained so far, you can take a look. ”

Zhang Min took a printed piece of A4 paper and spoke.

"The exact position of the 'far side of the moon' in our mouth should be from 86.025 degrees east longitude to 86.025 degrees west longitude, and the coordinates of the von Kármán impact crater are (44.8 °S, 175.9 °E), so I think the landing position of the probe should be controlled between 150 degrees east longitude and 30 west longitude!"

Gu Lu nodded in agreement, "That's right, but the scope can be narrowed." ”

"Has the geomorphological map of the far side of the moon taken by the probe come back?" Gu Lu asked with a smile.

"I've sent back some of them, Professor Gu, which one do you want to use? ”

"Please print me a copy of the topographic map around the von Kármán crater. ”

"Wait a minute. ”

Half a minute later, Gu Lu took a printed topographic map from Zhang Min's hand.

Gu Lu took out his pen and circled one of the areas, "You see that this area to the southeast of the von Kármán impact crater has a large area of undulating mountains, and there is a dry desert nearby, so I think it's ......."

Gu Lu and Zhang Min had a heated discussion.

More than half an hour later.

When the probe drove out of the far side of the moon, Gu Lu and Zhang Min finally determined the specific descent location of the probe.

（54.9°S，155.3°E）!

This is the optimal landing position that Gu Lu calculated.

Landing in the sky above this position, with a certain inclination, can achieve accurate landing of the detector, with a high fault tolerance rate.

Because of this, the intended landing position of the probe is northwest of the von Kármán crater.

Even if the final landing location is biased, there will be no crash of the probe landing in a bunch of mountains to the southeast.

It's the perfect landing spot!

"Is this position feasible?" Wu Zheng said in a deep voice.

"We need to confirm it again. Gu Lu's tone was solemn.

Although Gu Lu already has 100% confidence, at other times, Gu Lu may just let it go.

But in this case.

Just to be on the safe side, I need to double check!

Gu Lu does not allow the slightest deviation.

However, it will take another hour for the next probe to run to the far side of the moon.

"Are you hungry?" Wu Zheng said with a smile, and his tone was quite relaxed.

Gu Lu touched his stomach, "It's a little." ”

Wu Zheng didn't mention it, and Gu Lu didn't feel anything yet.

But now Gu Lu did feel the hunger in his stomach.

"Let's go find something to fill our stomachs, and we'll be there a tough battle soon!" Wu Zheng patted Gu Lu's shoulder with a smile.

"Is it okay to have you on this side of the command center without you?"

"It's okay, now they're all nervous to death, just let me go out and let them relax the atmosphere, otherwise it's not good to keep suppressing like this. ”

With that, Wu Zheng walked out of the command center with his arm around Gu Lu's shoulders.

The restaurant downstairs is not open at this point in time.

Wu Zheng took Gu Lu to the pantry on the top floor.

"Chief Engineer Wu, do you still have the leisure to come to us for coffee?"

Although it was already two o'clock in the morning, there were not many people in the pantry on the top floor.

One of the young men, who was about the same age as Wu Zheng, greeted Wu Zheng with a smile.

"I'm hungry, find something to eat to fill my stomach, can't you?" Wu Zheng rolled his eyes at the man.

After speaking, Wu Zheng went to the front desk to order a cup of coffee for himself and Simon, plus a few plates of snacks.

And the young man took advantage of Wu Zheng's time to order food, walked up to Gu Lu and introduced himself.

"You are Professor Gu Lu, hello, let me introduce myself, my name is Jiang He, and I am the person in charge of the Mars landing project!"