In the past three months, Tang Yue and Lao Mao have discussed this issue in private more than once.

After all, the self-sustainability of the Joint Space Station is limited. Although it is far from reaching its structural life, no one knows how long the space station can last when supplies are cut off. Tang Yue is really worried about leaving Maidong alone up there.

, if something goes wrong, neither he nor Lao Mao can help.

Another more serious problem is Ophiopogon japonicus's body. To be honest, the United Space Station is really not a suitable place for long-term living. No one likes to live in a narrow tube. If you have claustrophobia, it will be even more of a nightmare. In this kind of depression

In this desperate situation, the negative effects of weightlessness and radiation exceeded Tang Yue and Lao Mao's expectations. Maidong was losing weight rapidly, and she even began to lose her hair.

Tang Yue still has a gravity of 0.38 G on Mars, while Ophiopogon japonicus has almost zero gravity on the space station. The latter's living environment is much harsher.

Seeing the girl losing weight day by day, Tang Yue took the old cat and racked his brains, trying to find a way to let Ophiopogon japonicus fall to the ground safely.

Lao Mao said that this is completely technically impossible. Whether it is the space station or the Orion spacecraft, they never thought about entering the atmosphere from the beginning of their design - the day they entered the atmosphere was the moment they were scrapped and burned. The United Space Station is huge

The truss structure is like a huge Lego building block. This structure can only exist stably on a weightless orbit. Once it is affected by gravity and air resistance, the space station will quickly collapse.

Whether on the earth or on Mars, re-entry into the atmosphere is the most difficult and dangerous step in aerospace engineering. I don’t know how many spacecraft and detectors have failed at this step. In unpowered re-entry

, in order to slow down and cool down, the return vehicle must be designed into a blunt cone or bell shape. The Soviets briefly adopted a spherical return capsule, but later abandoned this plan because it was too dangerous.

"The current average flight speed of the Joint Space Station is 3.5 kilometers per second, which is equivalent to ten times the speed of sound." Old Cat said leisurely, "Do you know what this concept is? Just one 'tick' and the space station has already run out.

With a distance of seven miles, it only takes five minutes to fly from Beijing to Shanghai.”

"The total weight of the Joint Space Station is six hundred tons. We can calculate its momentum... 2.1x10∧9kgm/s, which is a very scary number." Old Mao continued, "It takes a lot of energy to slow it down.

energy, deceleration is the first difficulty we have to face.”

"The Orion 2 rocket engine can be used for reverse thrust," Tang Yue said.

"I'm not sure how much fuel is left on Orion 2. The last time we made the space station violently change its orbit, lowering and litering, it already consumed too much fuel." Old Mao shook his head, "But even if we can make the space station lower its altitude, it will

How? This is asking for a dead end... I have said that the structure of the space station cannot withstand such a large overload and high temperature. After entering the atmosphere, the surface temperature of the space station can exceed one thousand degrees Celsius, and it will burn into a pile of debris."

"Is there any cabin on the space station that can withstand such a temperature?" Tang Yue asked.

"Maybe...but just because the cabin can withstand it doesn't mean that the occupants can withstand it." Old Cat said, "That cabin will turn into a can roasted by high temperature, and whatever is inside will be cooked.

, just like roasting chicken in a simmering pot.”

"Overload and high temperature are the second difficulties we have to face."

Tang Yue was silent for a long time.

He knew that this problem was difficult to solve. Back then, space pioneers on Earth racked their brains to overcome the ablation problem of the return capsule. Finally, materials science provided the answer. Engineers covered the heating surface with high-temperature-resistant ablation materials.

, the heat is taken away by peeling off the insulation material, which saves the return capsule from being burned by high temperature.

But there is no such thing on the outer shell of the space station. The outer shell of the joint space station is made of metal, engineering plastics, insulation films and various bits and pieces. The irregular shape will greatly increase air resistance and form high-temperature accumulation areas in certain parts.

, if the space station plunges headlong into the atmosphere, the final result will be like throwing wax into a fire.

This is almost a replica of the Space Shuttle Columbia accident.

"The last step is to slow down. Even if you are lucky enough to survive the difficulties ahead, the space station is falling from the sky at hypersonic speeds several times the speed of sound. How can you ensure that the crew members will not fall to death?" Lao Mao asked.

, "There are no oversized parachutes on the space station."

Tang Yue scratched his hair and took a deep breath, "We still have the engine of Orion 2..."

"It's just a chemical-powered rocket, not a nuclear fusion engine. You have to realize that our fuel is limited." Old Cat interrupted him, "The rocket is not powerful enough to support the spacecraft to land safely in the atmosphere."

Tang Yue was a little helpless. He hoped that the next second the old cat would change the topic, come up with a "but", and then come up with a feasible plan.

"So it is completely technically unfeasible to land the space station safely." Lao Mao concluded.

After all, the human body is too fragile, and a problem with one link can be fatal. If the person in the United Space Station was not Ophiopogon japonicus but Optimus Prime, then there would be no need to go to such trouble.

What do you want to slow down?

What are you talking about overload?

What are you afraid of the high temperature?

Just let him jump down.

·

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Tang Yue was very frustrated, although this result was within his expectation.

He and Lao Mao couldn't keep making possibilities out of the impossible.

"Isn't it possible to just bring people down safely without considering bringing any supplies or materials?"

"It can't be done," said the old cat. "The most difficult thing is to make people land safely. It doesn't matter whether the can is round or flat, but there is a difference between the living and the dead. Think of the unlucky Comrade Komarov."

, when the rescuers pulled him out of the return capsule of the Soyuz spacecraft, he was burned to the point where only this piece was left."

The old cat gestured with his hands and saw a rectangle tens of centimeters square.

Tang Yue covered his face. He originally promised to take down Ophiopogon japonicus, but this promise may never be fulfilled. Ophiopogon japonicus can only stay up there until death.

"Mr. Cat, I am looking at this evolutionary history... Is there a relationship between Neanderthals and modern humans? Are they not our direct ancestors?" Maidong asked.

"Strictly speaking, there is a certain genetic relationship. Both Asians and Europeans have three percent of Neanderthal genes in their bodies." The old cat put on the headphones and turned to answer Ophiopogon japonicus's question.

, "But Neanderthals and ordinary humans, that is, late Homo sapiens, belong to different subspecies of humans. They are not your ancestors. Human beings originated in Africa. The first group to leave the African continent were Homo erectus, and the second group

The Neanderthals left Africa, and the third group of people who left Africa were Homo sapiens, the ancestors of modern humans."

"Does that mean the Neanderthals later became extinct?"

"Yes." The old cat nodded.

"Why extinction?"

"This is a long story..."

Tang Yue sat on a chair, with his chin clenched and his eyes staring at the computer screen. On the screen was a three-dimensional model of the United Space Station. The model was rotating repeatedly. Tang Yue looked at it in a daze.

It is really an unsolvable problem to let Ophiopogon japonicus land successfully.

This time is different from the last time delivering supplies. When delivering supplies, we only have to overcome the difficulties of natural conditions and mechanical failures. The Eagle spacecraft itself is capable of transporting supplies, but it is completely wishful thinking to land the space station safely. The space station does not have the capabilities at all.

This ability...

Tang Yue suddenly frowned.

"Old cat." Tang Yue reached out and pulled the old cat.

"What are you doing?"

"I...I have an idea that can overcome the difficulties you mentioned." Tang Yue said slowly, "Maybe it works. You can see if it works."

"What?" The old cat was surprised.
Chapter completed!