Over the past three months, Tang Yue and Old Cat had discussed this issue more than once in private.
The Joint Space Station's ability to sustain itself was ultimately limited. Although it was far from reaching its structural lifespan, no one knew how long the space station could last without supplies. Tang Yue was really worried about leaving Mai Dong up there alone. If something went wrong, neither he nor Old Cat would be able to help.
Another more serious problem was Mai Dong's health. To be honest, the Joint Space Station was not a suitable place to live in for a long time. No one liked to live in a narrow tube, and it was even more of a nightmare if one had claustrophobia.
In this depressing and desperate situation, the negative effects of weightlessness and radiation exceeded Tang Yue and Old Cat's expectations. Mai Dong's weight was rapidly decreasing, and she even began to lose her hair.
Tang Yue was on Mars, and at least there was 0.38 G of gravity, but Mai Dong was on the space station, and the gravity was almost zero. The latter's living environment was much worse.
Seeing the girl lose weight day by day, Tang Yue pulled Old Cat and racked their brains to find a way to safely land Mai Dong.
Old Cat said that it was completely impossible from a technical point of view. Whether it was the space station or the Orion spacecraft, they were never designed to enter the atmosphere. The day they entered the atmosphere was the day they were scrapped and burned.
The Joint Space Station was a huge truss-like structure, like a huge Lego building block. This structure could only be stable in a weightless orbit. Once it was affected by gravity and air resistance, the space station would quickly collapse.
Whether it was on Earth or Mars, atmospheric re-entry was the most difficult and dangerous step in aerospace engineering. Countless spacecraft and probes had failed at this step.
In an unpowered re-entry, in order to slow down and cool down, the retractor had to be designed in the shape of a blunt cone or bell. The Soviets briefly used a spherical retractor, but it was later abandoned because it was too dangerous.
"Now the Joint Space Station's average flight speed is 3.5 kilometers per second, which is equivalent to ten times the speed of sound," Old Cat said casually. "Do you know what this means?
With a 'tick,' the space station will have traveled seven miles, and it will only take five minutes to fly from Beijing to Shanghai. "
"The total weight of the Joint Space Station is 600 tons. We can calculate its momentum … 2.1 × 10 ² 9 kg/gms. This is a very scary number."
Old Cat continued, "It will require a lot of energy to slow it down. Deceleration is the first obstacle we face."
"We can use Orion II's rocket engine to do a reverse thrust," Tang Yue said.
"I'm not sure how much fuel is left on Orion II. The last time we violently changed the orbit of the space station, going down and going up, we used too much fuel." Old Cat shook his head. "But even if we can reduce the altitude of the space station, so what?
This is suicide … I've said before that the structure of the space station can't withstand such a large overload and high temperature. After atmospheric re-entry, the surface temperature of the space station will exceed 1,000 degrees Celsius. It will burn into a pile of debris. "
"Is there no cabin on the space station that can withstand such temperatures?" Tang Yue asked.
"Maybe … but just because the cabin can withstand it, it doesn't mean the occupants can."
"That cabin will become a can that's being roasted at high temperatures. No matter what's inside, it will be roasted. It'll be like roasted chicken in a can."
"Overload and high temperature is the second obstacle we have to face."
Tang Yue was silent for a long time.
He knew that this problem was difficult to solve. Back then, the space pioneers on Earth had racked their brains to overcome the problem of ablation of the capsule. In the end, material science gave the answer. Engineers covered the heating surface with ablative materials that were resistant to high temperatures, and by stripping away the heat from the insulation, they prevented the capsule from being destroyed by the high temperatures.
However, the outer shell of the Joint Space Station did not have such materials. The outer shell of the Joint Space Station was made of metal, engineering plastic, insulation film, and all sorts of other things. The irregular shape greatly increased air resistance, and at the same time, it formed high temperature zones in certain areas. If the space station plunged into the atmosphere, the final outcome would be like throwing wax into a fire.
This was almost a replica of the Space Shuttle Columbia's accident.
"The last obstacle is deceleration. Even if you have heaven-defying luck and survive the first obstacle, how can you guarantee that the occupants won't fall to their deaths when the space station descends from the sky at supersonic speeds that are several times faster than the speed of sound?" Old Cat asked. "The space station doesn't have a super-large parachute."
Tang Yue scratched his head and took a deep breath. "We still have Orion II's engine …"
"It's only a chemically powered rocket, not a nuclear fusion engine. You have to realize that our fuel is limited." Old Cat interrupted him. "That rocket isn't powerful enough to support a spaceship's safe landing in the atmosphere."
Tang Yue felt a little helpless. He wished that Old Cat could change the topic in the next second and say a "but" before coming up with a workable plan.
"Therefore, it's completely technically impossible for the space station to land safely." Old Cat made the final decision.
At the end of the day, the human body was too weak. A single problem could be fatal. If the Joint Space Station didn't have Mai Dong but Optimus Prime, then it wouldn't have been so troublesome.
What deceleration?
What overload?
What high temperatures?
He could have just jumped down.
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Tang Yue was depressed, even though this outcome was within his expectations.
He and Old Cat couldn't keep creating possibilities out of the impossible.
"You don't have to consider bringing any supplies or supplies. You just want to bring people down safely. Can't you do that?"
"It can't be done."
Old Cat said, "Landing people safely is the most difficult thing. It doesn't matter if the can is round or flat, but a living person is different from a dead person. Think about the unlucky comrade Komarov. When the rescuers dragged him out of the Alliance spaceship's return cabin, he was only left with this piece of burnt flesh."
Old Cat gestured with his hands. It was a rectangle that was dozens of centimeters square.
Tang Yue covered his face. He had promised to bring Mai Dong down, but this promise might never be fulfilled. Mai Dong could only stay up there until she died.
"Mr Cat, I'm looking at this evolutionary history … Is there a relationship between Neanderthals and modern humans?
They're not our direct ancestors, right? "Mai Dong asked.
"Strictly speaking, there is a certain genetic relationship. Whether it's Asians or Europeans, there are three percent Neanderthal genes in their bodies."
Tomcat put on the earpiece and turned to answer Mai Dong's question. "However, Neanderthals and ordinary humans — which is to say, late-stage Homo sapiens — are different subspecies of humans. They are not your ancestors.
Humans originated in Africa. The first group to leave Africa was Homo erectus. The second group to leave Africa was Neanderthals. The third group to leave Africa was Homo sapiens, the ancestors of modern humans. "
"In other words, Neanderthals went extinct?"
"Yes." Old Cat nodded.
"Why did they go extinct?"
"It's a long story …"
Tang Yue sat in his chair, propped up his chin, and stared at the computer screen. On the screen was a three-dimensional model of the Joint Space Station. The model rotated repeatedly. Tang Yue stared at it in a daze.
To let Mai Dong land successfully was an unsolvable problem.
This time was different from the previous supply delivery. During the supply delivery, they only had to overcome the difficulties of natural conditions and mechanical failures. The Eagle itself had the ability to deliver supplies, but to let the space station land safely was completely wishful thinking. The space station did not have the ability to do so …
Tang Yue suddenly frowned.
"Old Cat." Tang Yue reached out and tugged at Old Cat.
"What?"
"I … I have an idea that can overcome the difficulties you mentioned," Tang Yue said slowly. "It might work. See if it works."
"What?" Old Cat was shocked.
"Eagle." Tang Yue turned his head, his eyes shining. "The Eagle!"