Martian Day 2.

It took a whole day for Pang Xuelin and Watney to clean out the material cabin, and they moved all the living materials, experimental equipment, and medical supplies to the living cabin, and the originally spacious living cabin was suddenly packed.

In order to save food, the original three meals a day was changed to two meals a day.

Fortunately, the aerospace-grade peptide protein powder and vitamins are very sufficient, so the two of them will not be malnourished due to the lack of food.

Coupled with the fact that the gravitational acceleration on the surface of Mars is only half that of Earth, they burn many fewer calories in a day of heavy physical labor than they did when they were on Earth.

On the third day, Pang Xuelin and Watney recovered the main parachute in the MDV (Mars Landing Vehicle), cut it into a suitable shape with a knife, and laid it on the inner wall of the material module, including the floor, walls, and ceiling.

Water vapor condenses when it hits a film, which prevents water loss as much as possible.

"Pong, we have to find a way to compost, although the soil of Mars has all kinds of trace elements needed for plant growth, if it lacks bacterial activity and the specific nutrients provided by animals in their daily lives, even if the Martian soil is transplanted into the earth's environment, it will not be able to be planted. We've got to do some dirty work next! ”

Pang Xuelin recalled the scene of Mark Watney preparing soil in the movie, and was a little disgusted, but he still said: "Watney, you are a botanist, you can directly command what you need!" ”

Watney laughed: "The excrement of our perch chamber will be packed and thrown out after vacuum drying, I need you to make a trip to EVA to collect these things, the microorganisms in it are estimated that they have all died in the atmosphere of Mars, but all kinds of proteins, sugars, and fats are still there, we need to add water to stir and ferment this thing, and the bacteria in the perching chamber will soon be able to grow on it again." We'll have to put up with it, though, the more stinky this thing is, the better, so you'd better get a few more nasal plugs. “

"No problem, but Watney, can you not talk about it at dinner in the future? To be honest, listening to you while eating this lump of aerospace food is really hard to swallow! ”

Watney couldn't help but be stunned: "I'll try my best!" ”

"Hahahaha......"

The two of them looked at each other and laughed, which was a rare joy in such an environment.

After laughing, Pang Xuelin said:

"Watney, I think there's another issue that we need to pay attention to."

"What's the problem?"

Pang Xuelin said: "After the material module is changed to the planting module, this will become the foundation of our survival on Mars, and we must ensure that the planting module can operate normally in the next few years, so I want to close the airlock on the side of the planting module, and in addition, the electronically controlled gate between the living module and the planting cabin will also be changed to a mechanical gate." In addition, we test the air pressure, temperature, humidity, gas composition, etc. of the planting cabin every day, and do a good job of filing it just in case. “

In the movie, Watney could have survived on Mars for a longer time, but it was the airlock that accidentally exploded, destroying all the potatoes he had grown, and he almost didn't wait for rescue.

Watney pondered for a moment and said, "You have a point, leave this to me, and in the next few days, our focus will be on the preparation of soil and water!" “

……

Martian day 5.

It took three days for Pang Xuelin and Watney to complete the composting work. In addition, the two transported more than 20 cubic meters of Martian soil to the planting chamber and spread it evenly in the planting cabin.

The process of composting is hard to describe, anyway, the smell of the two of them don't want to smell it again in their lives.

Next, it's time for the most dangerous water production.

To prepare water with hydrazine, under normal circumstances, it is enough to burn hydrazine.

However, hydrazine is a highly toxic chemical that can strongly erode people's skin and eyes, and may also cause liver damage after exhalation.

Direct combustion is easy to cause hydrazine volatilization, and the danger is too great.

The two came up with a way to first drop liquid hydrazine into a metal iridium bowl, which can catalyze hydrazine, decomposing it into nitrogen and hydrogen, and then burning the hydrogen to get water.

Of course, this process is not much easier and less dangerous to operate.

Pang Xuelin and Watney spent another two days using some discarded materials and the experimental equipment originally carried by the material cabin to create a simple chemical reaction experimental device.

Theoretical calculationsPang Xuelin did not have a fake Watney hand, this guy undercounted the small disturbance caused by his breathing to the experiment in the movie, and was directly blown away by hydrogen when he made water for the first time.

After Pang Xuelin considered all aspects, he asked Watney to help check again, and after making sure that there were no problems, the two put on their bulky EVA space suits and started their first water-making trip.

"Let's get started!"

Pang Xuelin gently unscrewed the valve of hydrazine, and the hydrazine slowly dripped into the iridium bowl along a slender glass pipe, and then quickly bubbled up to release the heat.

This reaction takes place semi-enclosed in an ultra-high molecular weight polyvinyl chloride film, and hydrazine is catalyzed by iridium to decompose into nitrogen and hydrogen.

The density of nitrogen is slightly lighter than that of air, so it can remain in the film, and the hydrogen is exported along a slender glass tube above into the gas collector cylinder, which is filled with water, the short pipe goes in, the long pipe comes out, and as long as the water in the gas collector cylinder is all discharged, the long pipe drain is ignited.

The water vapor produced by the combustion of hydrogen passes through a water circulation system and a condensing water collector made by the two men

Soon, all the water in the cylinder was expelled by hydrogen, and Watney created an electric spark at the drain, and a pale blue flame began to burn, and Watney laughed and said, "Great, we made it!" ”

Pang Xuelin also breathed a sigh of relief.

The compression pump at the base of the MAV is used to compress the carbon dioxide, which is then converted into oxygen by the oxygenator, and finally the oxygen and hydrogen are burned to obtain the most valuable water, which is easy to say but too difficult to do.

The slightest mistake in any one link may lead to the failure of the experiment.

A day later, a 50-litre tank of hydrazine was burned, the condenser contributed nearly 50 litres of water to them, and the water circulation system collected 25 litres.

"Pang, we have a full 600 liters of hydrazine, and in two weeks, we can collect 1.2 tons of water."

Watney excitedly.

With so much water, he can even partially modify the living pod, so that not only can the calorie problem be solved, but he can even grow some vegetables to try it.

Pang Xuelin didn't respond, looking at the water in the bucket and frowning.

Watney wondered, "Pong, what's wrong with you?" ”

Pang Xuelin shook his head and said, "Don't you think it's strange? 50 liters of hydrazine should make 100 liters of water, but we only collected 75 liters. “

Watney laughed, "I thought you were worried about something? Didn't you notice? There are a lot of water droplets on the bulkhead and dome of the planting cabin, plus the part absorbed by the soil, so it's normal to have such an error, right? ”

Pang Xuelin said: "Do you think this water adds up to 25 liters?" ”

Watney frowned and said, "So what do you mean?" ”

Pang Xuelin said: "You go check the No. 1 oxygen storage tank to see if the oxygen storage is more or less." ”

"Good!"

Watney checked the reserves in the oxygen tank, and soon returned to the planting pod, saying, "Pang, it's strange that the liquid oxygen content of our oxygen tank has risen by almost seven liters. ”

Pang Xuelin said: "That's right! Watney, you see, we used the compression pump left by MAV today to produce 50 liters of liquid carbon dioxide, and then converted this carbon dioxide into oxygen with an oxygenator, it stands to reason that if all the oxygen reacts with hydrogen, then the oxygen content in the oxygen storage tank should be basically the same as before, but now, the liquid oxygen content has risen, indicating that there is still some hydrogen that has not reacted with oxygen, and in our hydrazine storage tank, hydrazine has been empty, what does this mean? ”

Watney also reacted at this time, with a look of horror on his face: "What do you mean?" Some of the hydrogen escaped through the flames...... What is the explosive limit of hydrogen? ”

Pang Xuelin said: "4.0%~75.6%, we have an atmospheric analyzer in the rover, and we will take the gas in the cabin out for analysis. ”

As soon as he said and did, Pang Xuelin immediately found a ziplock bag, and then walked out of the perching module with Watney in an EVA spacesuit and entered the rover.

Soon, the test results came in.

The proportion of gases in the sample was 54% nitrogen, 9% oxygen, and 37% hydrogen.

The two couldn't help but look at each other, the planting cabin they were staying in just now was a super big bomb.

Pang Xuelin breathed a long sigh of relief and said: "We should be glad that the hydrogen combustion was carried out in the condenser before, and the hydrogen content in the condenser did not reach the explosion limit, so we escaped the catastrophe, but now, as long as a small static electricity in the planting cabin can cause a big explosion." ”

Watney frowned, "So what do we do next?" ”

In this case, let alone water production, even returning to the perching chamber will be terrifying.

Pang Xuelin smiled bitterly: "Let's stay in the rover first, there will definitely be a way." ”

There is no such scene in the movie, and when Watney made water, except for a small explosion caused by a miscalculation at the beginning, it was done with ease. But now, it's different!

Pang Xuelin couldn't help frowning.

That night, both Pang Xuelin and Watney couldn't sleep well in the rover.

The carbon dioxide filter inside the rover and the carbon dioxide filter inside the EVA spacesuit will last up to two days, and they will have to return to the perching module.

But the question now is what to do with the mixed air in the perch, even a tiny spark from static electricity can detonate the entire perch, and they have to come up with a safe enough way to dispose of it.