Tang Yue's face was stiff and pale, and cold sweat slid down his cheeks.

The RD-0172 engine in the payload compartment of the Eagle spacecraft is a small rocket used for safe escape during the launch phase, or for maneuvering orbit changes in the command module, which has quite limited thrust and working time.

Under normal circumstances, the propellant of the RD-0172 rocket must be sufficient, because the lander is a delicate and meticulous job to lift off into orbit again, and it is necessary to select the appropriate launch window, and it requires close cooperation between the Earth Control Center, the Kunlun Station, the Joint Space Station and the lander, and the Earth Control Center needs to carefully formulate plans and plans, and the Kunlun Station and the space station provide remote guidance, as well as the adjustment and control of the astronauts on the lander.

In previous Mars missions, the lander and the space station rendezvous and docking are all using a fast docking scheme, after the lander enters orbit, it will enter the rendezvous procedure after orbiting Mars for a week, and it will not take more than two hours from beginning to end, which is very simple and easy, so the propellant of the RD-0172 in the payload compartment cannot be used up at all, and there is redundancy every time.

This gave Tang Yue a big illusion.

Let him think that rendezvous and docking is a very easy job.

"When did you get the illusion that you can connect casually?" The old cat asked, "In the past, there have been so many successful docking, because you have the perfect cooperation of the earth, Kunlun station, the joint space station and the lander behind you, and there is a large group of people helping you keep an eye on it, you see what we have left now?" ”

The earth is gone.

Due to the influence of bad weather, Kunlun Station was also unable to provide reliable remote positioning and guidance.

Mai Dong is the only one on the United Space Station, she is not an experienced professional astronaut like Captain Wang, and letting her be in charge of the entire rendezvous and docking procedure alone is really rushing ducks to the shelves.

And finally, the Eagle...... The Eagle spacecraft to be launched tomorrow is a pure cargo ship with no one on it, just compressed cookies and sandwiches, and you can't expect sandwiches to work with you.

Tang Yue sat down slowly, he figured out what the old cat meant, the strength of his body was withdrawn little by little, and his skin became cold little by little.

He still thought that everything was ready, only the east wind was owed.

The old cat was broken, and Tang Yue realized that this plan was full of loopholes and flaws, and there were possible problems in every link, and it was not vulnerable at all.

They had to launch an unmanned cargo spacecraft in an overwhelming sandstorm without monitoring and guidance, and then let the unmanned spacecraft find the space station on its own, complete the rendezvous and docking, and only allow one failure.

It's like dropping an eight-year-old kid who has never traveled far in a Beijing subway station, giving him a map and letting him go to Shanghai alone, and then patting him on the shoulder and telling him "You can only go wrong once".

"Damn, you...... Why didn't you tell me sooner? Tang Yue muttered.

"Where did we have time to talk about this before?" The old cat replied, "Have we rested these days?" ”

Tang Yue was a little distracted, his hope was too slim, it was too slim.

Without the remote control and guidance of the Kunlun station and the joint space station, it is impossible for the Eagle spacecraft to successfully change orbit, and the rendezvous and docking is a very meticulous work, and the lander and the joint space station are flying at a high speed of three kilometers per second when they are running, but their relative speed cannot exceed five meters per second when docking.

It's like two planes flying at ten times the speed of sound, they need to get closer in flight, so close that the pilots of the two planes can shake hands with each other.

If there is a slight mistake, the machine will be destroyed and people will die.

"What is the probability that the Eagle spacecraft will be able to dock automatically?" Tang Yue asked.

The old cat pondered for a while, "Unless the computer of the Eagle spacecraft can perfectly control the lander, execute every step accurately, and make no mistakes with a decimal point, it will be possible for it to dock successfully...... But this is ideal, relying only on the Eagle spacecraft's own navigation, there will always be a slight deviation. ”

"Because the objective conditions cannot reach the ideal state, the influence of the external environment will gradually accumulate errors, such as gravity, wind speed, and the working state of the engine, so the lander needs external instructions to correct it." Lao Mao continued, "This kind of external command can be the guidance of the Kunlun station, the guidance of the space station, or the adjustment of the crew on the lander itself. ”

"Without external corrections, it is almost impossible for the Eagle spacecraft to dock successfully?" Tang Yue asked.

"There is very little hope."

"Possibility!" Tang Yue gritted his teeth and said, "I want to know the probability!" What is the probability of successful docking? ”

"No more than one-twentieth."

"The propellant of the RD-0172 engine is enough only twice?"

The old cat nodded, "If the first rendezvous fails, then the remaining propellant will only be enough for one time, and if the second one fails, then the Eagle spacecraft will become space junk floating in orbit." ”

Tang Yue has no choice, he can only try twice, and the total probability of success is up to 1 in 10.

He suddenly felt so tired that he didn't want to say a word.

Every number that the old cat spits out of his mouth is precisely calculated, mathematics is really a beautiful and cruel thing, it is the manifestation of the rules and logic of the universe, unshakable, no matter how much strength you have, you can't forcibly change a calculation result even a million decimal places of a certain number.

A tenth is a tenth.

This probability is an irrevocable death sentence, which is not given by man, but by the will of the world.

It is impossible for man to fight against the universe, the radius of Mars is 3,389 kilometers, you can't turn it into 4,000 kilometers, the gravitational acceleration on Mars is 0.38 G, you can't turn it into 0.4 G, all the parameters and rules have been firmly welded to death as early as the beginning of creation.

So their verdict is unshakable.

The old cat didn't speak, one person and one cat sat in the dim light, and only the hum of the OGS system was left in Kunlun Station.

"So where is our hope?" Tang Yue's eyes were open, his gaze blank, "Didn't you say that we were going to find the last hope buried in the impossible?" Where is this hope? Where is it? ”

The old cat poked him in the chest.

"Here."

Tang Yue was stunned.

"Mars is dead, the Eagle spacecraft is dead, the laws of physics and mathematics are dead." "But you are alive, you are the only living person on this planet, and if even you die, then the last hope will be lost." ”

Tang Yue looked at it in a daze.

The old cat's face was calm.

"Do you think man can overcome the universe?" The old cat suddenly asked, "I don't think it is possible for man to defeat the universe, but he can defeat himself." ”

Tang Yue froze, his face twitched, and then his voice began to tremble.

"You...... What do you mean...... And saved? ”