"Pang, establishing a mathematical model requires accurate data support. We produce carbon dioxide every day when we breathe. After the potatoes in the planting chamber eliminate the respiration every day, the amount of carbon dioxide absorbed by photosynthesis, the difference between this, how many green leaf plants need to be planted to maintain the balance of carbon dioxide in the habitat chamber, we must accurately measure it."

"In addition, if we grow new green leafy plants, we still need water, fertilizer, and water. If we grow new green leafy plants, there are still 500 liters of water in our water circulation system. In addition to our basic drinking and washing guarantee, we can take out three hundred liters of 300 liters of hydrazine in the mdv, which can produce 200 liters of water. One cubic meter of soil requires forty liters, so we can still make about 12.5 cubic meter of soil. The biggest trouble lies in fertilizer. The plant seeds we have left now are basically mainly vegetables, and we cannot provide us with a large amount of calories. Therefore, once new green leafy plants are planted, the potato yield will definitely drop, which will cause food shortages at that time..."

Pang Xuelin frowned and said after a while: "Watney, I was thinking, maybe we can consider moving to the roaming car to live. We still have 2,300 hours of small carbon dioxide filters. We work in the roaming cabin for twelve hours a day, and the remaining twelve hours a day rest in the roaming cabin. On the one hand, this can extend the use time of the spare carbon dioxide filter in the roaming cabin, and on the other hand, it is also convenient for us to experiment. There is an atmospheric analyzer in the roaming car, and we can adjust our plan according to the changes in the carbon dioxide content!"

Watney lowered his head and pondered for a moment, and said, "This method is good!"

That night, the two moved into the rover.

During the day, he entered the habitat cabin and began to make water-making work with familiarity.

One hundred liters of hydrazine were converted into 200 liters of water in just three days. For this reason, they also consumed nearly one hundred liters of reserve liquid oxygen.

But they originally planned to work twelve hours a day, but they couldn't continue in the evening on the first day.

Because the carbon dioxide concentration in the habitat chamber exceeded 2,000ppm within twelve hours, it had a significant impact on Pang Xuelin and Watney.

The two had to activate the standby carbon dioxide filters for the perch tank to absorb the carbon dioxide in the perch tank.

It was not until two hours later that the CO2 in the perch tank dropped to a safe concentration, and they turned off the CO2 filter again.

After three days of testing, Pang Xuelin and Watney discovered that the potatoes currently grown in the living compartment can only absorb two people's breaths for ten hours a day to produce carbon dioxide, and the rest must be solved by a carbon dioxide filter.

Because they are basically in high-intensity working state in the habitat cabin, the carbon dioxide produced in twelve hours is equivalent to two-thirds of the carbon dioxide content of two people exhaled in a day.

"This is good news. Even if we do nothing next, using potatoes in the planting cabin, we can extend the working time of the spare carbon dioxide absorber in our habitat to 30 days. If we choose the right crop, it may really keep the carbon dioxide produced by our breathing in a basic balance. Even if it is slightly exceeded, it can greatly extend our working time on Mars."

Pang Xue Lindao.

Watney nodded and said, "I have chosen the plants we will plant next, so plant tomatoes! The dozens of crops we carry this time include C4 crops with high photosynthesis efficiency, such as rice and corn, but these plants have a harvest period and have high requirements for moisture and fertilizer, which is not suitable for us to grow. Tomatoes are more suitable. Tomatoes are herbaceous plants, which like light, with a light saturation point of 70,000lx, and a suitable light intensity of 30,000-50,000lx. They have strong carbon dioxide absorption capacity. Moreover, tomatoes are different from potatoes. As long as they have the right temperature and humidity, they can grow year-round, so they can basically ensure uninterrupted photosynthesis for 24 hours. Unfortunately, we did not carry single-cell algae this time, and the unit volume photosynthesis efficiency of that thing is high. As long as it is well managed and arranged in the planting cabin, it is enough for us to use it!"

Pang Xuelin smiled and said, "You are an expert, listen to you!"

Next, after soliciting opinions from the expert group on Earth, Pang Xuelin and Watney maintained their work and rest time for twelve hours to rest in the rover and work in the twelve-hour perch cabin.

In order to ensure communication, Pang Xuelin connected the communication equipment of the rover to the Mars Pathfinder landing compartment, so that it can not only contact the earth in the perch cabin, but also in the rover cabin.

During the twelve-hour rest period, the carbon dioxide exhaled by two people is only one-third of the breath of a day. When the twelve-hour habitat is working, the two-hour habitat backup carbon dioxide absorber can basically maintain the carbon balance of the habitat.

In this way, the spare carbon dioxide absorber for the habitat that could only be used for twenty days can be extended to 240 Martian days.

The 2300-hour small carbon dioxide absorber can also be extended to 145 Martian days.

When the small carbon dioxide absorbers are used up, they enter the habitat chamber to use the oxygenator to spare carbon dioxide absorbers, and live for up to four to five days.

150 Martian days.

This is the limit of growing tomatoes at present. As for how long it can last after planting tomatoes, Watney can't determine.

The situation is really bad.

But Pang Xuelin and Watney still adjusted their mentality as much as possible and devoted themselves to tomato planting.

After half a month, the two transformed the original living compartment into a tomato planting compartment, with a total of 50 square meters of soil. Pang Xuelin and Watney specially transplanted half of the cooked soil in the potato planting compartment into the tomato planting compartment, and the newly made soil was reburied into the potato planting compartment.

This may have a very bad impact on the production of potatoes in the second season, but in order to ensure the survival rate of tomatoes, the two of them could not care about so much.

...

201 Mars Day.

[19:20] jpl: Xuelin, I am Tian Mu. Your latest data has been received. A simulation cabin on Earth has been specially established that is basically the same as your environment on Mars. Based on the tomato photosynthesis related data provided by you and the laboratory, simulation operations are performed on supercomputers. The results show that 50 square meters of tomatoes can absorb five-sixths of the carbon dioxide produced by you after they are ripe with potatoes. The remaining sixth must be solved through your carbon dioxide absorber. Excluding the problem of carbon dioxide treatment capacity reduction caused by the potato harvest season, it is initially estimated that you still have 400 Martian days to survive. My colleagues are working overtime and will launch supplies next month, which contains a large amount of food and a spare molecular sieve used to repair the oxygenation machine. It is initially expected that it will arrive before the 585th Mars day!
Chapter completed!