The next morning, Pang Xuelin woke up from hunger. As soon as he opened his eyes, he saw Watney chewing an energy bar.

"This is what I found in the car. It was probably left by Martha and the others when they went on a mission. There are four of them in total, which can be used as our food today."

Pang Xuelin took the energy bar, tore open the packaging and stuffed it into his mouth and started chewing it.

With some food in his stomach, Pang Xuelin took a breath and said, "Watney, have you thought of any solution?"

Watney shook his head and said, "The only way I can think of is to open the air lock chamber and let the air inside overflow, but in this way, the seeds of the plant in the living compartment and the bacteria produced by our fertile fertilizer will die from cold and hypoxia. At that time, we will not be able to bear it for a year. Alas, it would be great if there was air separation equipment..."

Pang Xuelin suddenly moved in his heart and asked, "What did you say just now? Air separation equipment?"

Watney said: "Yes, air separation equipment, but we don't have this thing."

Pang Xuelin said: "But we have an atmospheric regulator!"

Watney was slightly stunned and said, "The atmospheric regulator can only adjust the oxygen content. It can reduce the temperature to 90k at the lowest level, so that the oxygen can liquefy, and the nitrogen at the condenser point 77k can remain gaseous. However, the condenser point of hydrogen is only 21k, and we can't separate the hydrogen."

Pang Xuelin laughed and said, "We don't need to separate hydrogen. We just need to separate oxygen. As long as the oxygen concentration in the residence cabin is reduced to a certain level, no matter whether we ignite or do, the hydrogen will not explode. At that time, we can use an oxygen tank to spray oxygen into the air, and then use batteries and wires to create electric sparks, so that the hydrogen in the residence cabin can be burned controllably, and the hydrogen can be removed slowly."

Watney said: "But if the oxygen content is too low, bacteria and plant seeds will still die!"

Pang Xuelin couldn't help but frown. If this still doesn't work, he really has no good idea.

"Wait! I have a way to keep plant seeds and bacteria active!"

Watney Dollar.

"What's the solution?"

"We can reduce the oxygen concentration to a certain level, about one percent, and then lower the temperature in the habitat to freezing point. At that time, whether it is plant seeds or bacteria, they will enter a hibernation-like state, and the oxygen concentration of one percent is impossible to make the hydrogen explode. In this way, we don't have to worry about not being able to plant it in the future!"

Pang Xuelin's eyes lit up and he said, "Okay, let's do that!"

This method is simple to say, but it is very troublesome to do.

The two of them ventured back to the perch cabin, first adjusting the temperature in the perch cabin to freezing point, then activate the atmospheric regulator to separate the oxygen, and only when the oxygen content in the perch cabin dropped to one percent, they stopped working.

Then, Pang Xuelin and Watney found a can of jet-type pure oxygen and made a small electric spark generator. It took them a whole day to clear the hydrogen in the perch cabin.

In the next month, Pang Xuelin and Watney controlled the daily water production to less than 40 liters, and the remaining time was to clean up the hydrogen accumulated in the habitat due to water production.

After 32 Martian days, the two used 500 liters of hydrazine to create a full ton of distilled water.

The remaining one hundred liters of oxymethylene are used as emergency reserves.

To this ton of water, they added 200 liters of water to the water circulation system, and the remaining 800 liters of water, all mixing them with twenty cubic meters of Martian soil.

...

The 35th Mars Day.

Today is a big day for Pang Xuelin and Martin Watney.

They will be recorded in history for the first time in history of humans who have engaged in agricultural activities on Mars.

Today's planting results will also become the foundation for their future survival on Mars.

However, before planting, they have to check the status of the equipment inside the entire habitat.

There are three air gates in the living compartment, which are located in the living compartment, the planting compartment and the energy compartment.

The planting cabin and the energy cabin are connected with gates and living cabins respectively, and the three cabins are arranged in a font shape.

In order to prevent accidents, Pang Xuelin and Martin Watney checked the heating system, main battery pack, nitrogen and oxygen storage tank, lighting system, computer system, water circulation system, air conditioning system, etc.

Subsequently, the two completely closed the electrical control system of the air gate on one side of the planting cabin, adjusted it to a mechanical control state, and then sealed it.

For a long time in the future, they will no longer enter and exit the air gate on the planting pod.

As for the gate between the living compartment and the planting compartment, they also closed the electronic control system and chose robotic control.

The two agreed that at any time, whenever they enter and exit the planting cabin, they must manually close the hatch door.

After all the preparations were completed, the two began formal planting work.

Watney had cut the potatoes one by one and dug a hole in the soil in the planting compartment.

Pang Xuelin learned from Watney and buried half of the potato in the pit, poured a spoonful of fertile fertilizer, added a spoonful of water, and then covered the Martian soil.

It took two hours to get the planting area just over one hundred years.

"Pang, we will definitely survive on Mars!"

Pang Xuelin and Watney looked at each other and laughed.

...

After coming out of the planting cabin, closing the cabin door, the two of them used the microwave to heat up two packs of fried rice to treat themselves.

Pang Xuelin said: "Watney, next, we almost have to consider how to restore communication with the earth."

Watney took a sip of the drink soaked from the peptide protein powder and frowned: "Pang, I'm afraid the only way now is to go to Schiaparelli and use the mav (Mars liftoff vehicle) prepared for Ares IV that landed there in advance in advance to restore contact with the earth."

Pang Xuelin shook his head and said, "The long journey of 3,200 kilometers is too dangerous to rely on a roaming car alone. I don't recommend doing this."

Watney shrugged, "Then can we have a better way?"

Pang Xuelin smiled, slowly put a spoonful of rice into his mouth, and said, "It may not be possible to have no solution."

Watney was slightly stunned and said, "What's the solution?"

Pang Xuelin stood up and took down a topographic map hanging on the wall, typed an x ​​number on it, and said: "We are currently in the Asidari Plain, with a latitude of 31.2 degrees north latitude and 28.5 degrees west longitude. Do you remember the training we participated in before participating in the Ares program? Before we officially landed on Mars, we used a Mars rover to conduct large-scale unmanned exploration activities on Mars."

Watney looked at the x-sign on the map, his eyes getting brighter and brighter: "Mars Pathfinder, I understand, Mars Pathfinder!"

The Mars Pathfinder is an unmanned expedition spacecraft launched by the Nasa in December 1996. It landed on the surface of Mars on July 4, 1997. In addition to the landing cabin, there is also a 10.6-kg Mars Rover Forester. It was originally planned that the Mars Pathfinder would work for one month a week, but in fact it worked for three months and gained a lot of unprecedented Martian intelligence.

Pang Xuelin said: "The Mars Pathfinder is located at 28.9 degrees north latitude and 29.6 degrees west longitude, and 800 kilometers southwest of ours. At the beginning, it stopped working just because it was out of power. As long as we pull it back, we can use it to restore communication with the earth. And now it has been so long, I think the Ares Plan Command should find that we are still alive!"

Watney nodded and said, "You are right. It's only a distance of 800 kilometers, and a round trip of 1,600 kilometers. Our rover can run up to three to four hours. If we calculate at a speed of 30 kilometers per hour, we can drive up to one hundred kilometers per charge. The problem is that the power of the rover still needs to maintain the temperature in the car, so one can only walk up to fifty kilometers per charge. And after this journey is completed, it will take us three to four hours to fully charge. We can walk up to one hundred kilometers a day, which means that if our rover wants to bring back the Mars Pathfinder, it will take at least sixteen days. In addition, we have to carry enough liquid oxygen, carbon dioxide filters and other equipment, and have sufficient food guarantee... "

Pang Xuelin smiled and said, "I have a way to reduce the resources consumed on the road by half."

Watney wondered, "What's the solution?"

Pang Xuelin said: "Do you still remember the radioisotope thermal battery in mav? (rtg)"

Watney was slightly stunned and said, "Isn't that thing buried by Commander Lewis' order?"

Radioactive isotope thermal battery (RTG) is a device in MV.

As a Mars launch vehicle, the mav is the only equipment for astronauts to return.

It will soft-land at a predetermined location a few years before the astronauts land on Mars, and then wait for the astronauts to arrive, and when they need to return, they will take a MV to leave Mars and dock with the Hermes spacecraft.

In order to ensure that the mav is reliable in an unmanned state and can conduct system self-tests in a timely manner, scientists installed radioisotope thermal batteries on the basis of solar cells.

This radioisotope thermal battery (RTG) contains 2.6 kilograms of plutonium 238. This thing is very unstable and can decay and release radiation and energy at all times. It can generate about 1,500 watts of heat and 100 watts of electricity.

Pang Xuelin said: "We can dig it out and put it in the roaming car, and use it to heat the air in the roaming car, so that the roaming car does not need to consume extra electricity to keep it warm."

"This is a good method!" Watney clapped his hands: "In this case, we can only take eight days to bring the Mars Pathfinder back! And going to Schiaparelli impact craters in the future can also help us save a lot of time."

Pang Xuelin said: "It's true, but you don't have to go this time. I'll just drive over. On the one hand, you need to keep an eye on the planting cabin. This is the fundamental reason for our survival on Mars. There must be no problems. On the other hand, if I am the only one, the consumption of carbon dioxide absorbers and liquid oxygen can be reduced by half. We must save resources now."

Watney hesitated for less than a second before accepting Pang Xuelin's statement.

"Okay, then we'll dig out the rtg tomorrow, test the rover, and then set off."

"good!"
Chapter completed!