222nd Martian Day.

[17:21] JPL: Xuelin, I'm Tian Mu, and I'm on a call to you in Wenchang through Pasadena. We've calculated your orbit change plan, and Hermes has reached the limit of MAV at the orbital altitude and speed of Mars, and you guys are too risky this time. The journey of more than 3,200 kilometres from the plains of Asidaria to the Schiapallelli crater was a challenge for Watney. And once the MAV of the Schiaparelli crater is activated by Watney, then the Ares 4 project will definitely have to be delayed for one to two years, and you will have to spend at least 1,500 Martian days on Mars alone, so be prepared.

[17:36] Perch: When I made this plan, I was mentally prepared. If we don't take risks, we can't do it, even if we plant 50 square meters of tomatoes, our CO2 absorbers will only last until the 600th Martian Day, and we have no choice. Watney will be training for the next step, and we're certainly not kidding with our own lives.

[17:50] JPL: Okay, the Ares command has recalculated the amount of materials that Hermes needs to carry on this mission, and it is expected that half a month later, the Long March 9 carrier rocket will be launched from the Wenchang Satellite Launch Center on the "gluttonous" unmanned cargo spacecraft, and will rendezvous and dock with Hermes. Hermes will enter Mars orbit on the 445th Martian Day, and we have reserved five tons of supplies for you, do you have any personal suggestions?

[18:18] Perching Module: Hermes is not entering Mars orbit twice as fast as usual, and you can guarantee that these five tons of supplies will reach me without being damaged during the landing?

[18:36] JPL: We've modified the Gluttony cargo spacecraft, and the supplies you're going to get to it will be packed in a five-meter-diameter flexible chamber made of metamaterial aerogel, and when Hermes enters Mars orbit, the Gluttony cargo spacecraft will be released, and the Gluttony cargo spacecraft will use the remaining fuel to maneuver and change orbits, and then make a hard landing on the Asidaria Plain. At an altitude of about 10,000 meters above the surface of Mars, the flexible chamber will be separated from the Gluttony cargo spacecraft. The whole landing process is completed by AI, and the preliminary estimate is that the circumferential radius of the landing accuracy is about five kilometers, and then we will mobilize the satellite to help you locate the flexible supply module, and you can drive the rover to tow the supply module back.

[18:48] Perching Cabin: Glad to hear this, as for the supplies, I personally suggest that the food supply occupy less than one ton, and the remaining materials are as follows: at least twenty meters long water circulation system pipes, high-pressure water pumps, air compressor accessories, communication equipment accessories, oxygenator molecular sieves, nickel-metal hydride batteries, cables, fiber optic cables, various corresponding interfaces, solar cell packs, carbon fiber canvas for the perching cabin, sealing rings, rover parts, and it is best to bring some single-celled algae as well as incubators. The most important thing is that the more carbon dioxide absorbers, the better, to prevent the oxygenator from becoming irreparable. The above is only my personal opinion, and you can decide the specific type and quantity ratio of supplies.

[19:02] JPL: Roger, we'll draw up a list of supplies as soon as possible based on your comments.

……

Perhaps it was the previous accidents that drained Pang Xuelin and Watney's bad luck, and then things went unexpectedly well.

240th Martian Day.

The Long March-9 carrier rocket was successfully launched, sending the "Taotao" unmanned cargo spacecraft, weighing more than 60 tons, to low-earth orbit.

241st Martian Day.

After several orbit changes, the unmanned cargo spacecraft successfully docked with Hermes, which took advantage of the Earth's gravitational slingshot effect to accelerate its flight to Mars.

255th Martian Day.

The living pod tomato had grown almost knee-high, and it was green.

260th Martian Day.

The latest data suggests that as long as one hour a day the capsule's CO2 filter is turned on is enough to keep Pang Xuelin and Watney alive.

So Pang Xuelin and Watney moved their home from the rover back to the perching pod.

In the middle of the harvest they had another crop of potatoes.

Due to insufficient fertilizer, the number of potatoes this season was only 200 kilograms, a significant decrease from the first season, but still within the acceptable range of Pang Xuelin and Watney.

The temporary relief of the food problem and the fact that the carbon dioxide absorption problem is also minor do not mean that Pang Xuelin and Watney can relax, and there is more work waiting for the two of them.

Watney had to travel 3,200 kilometres to reach the Schiapallelli crater, and the difficulties were enormous, starting with a massive overhaul of the rover.

For example, the first problem they faced was to find a way to fit the CO2 absorber into the roost module.

There are currently 1,600 hours left for small CO2 absorbers and 300 hours for perching cabin CO2 absorbers.

It would take at least 30 to 40 days for Watney to cross a distance of 3,200 kilometers, and he had to be given 50 days in between, given the redundancy of the mission.

This meant that he needed 1,200 hours of CO2 absorbers.

Renovating the rover requires at least two hundred hours of small carbon dioxide absorbers, and after Watney leaves, Pang Xuelin will have to leave a margin of 300 hours. In addition, before Watney left Mars, the two needed to carry out EVA missions due to various accidents, so the small carbon dioxide absorber could only leave Watney for a maximum of 900 hours, and the rest was supplemented with the carbon dioxide absorber of the perching module.

The capsule's CO2 absorber is now available for two people for 300 hours, and Watney will depart on Martian Day 390, leaving at least 150 hours to spare.

If Watney is given its own use, it can be used twice as long and is therefore enough for Pontney to cover a journey of 3,200 kilometres.

The problem is that the CO2 absorbers in the perching chamber are too large, and there is not enough space for the CO2 absorbers in the roost after the rover is loaded with food and small CO2 absorbers.

So the experts of the Ares Project Command made a big brain hole, Pang Xuelin and Watney used an electric drill to make a big hole in the roof of the rover, and then used the MDV parachute to make a large balloon on the roof of the car, and put the carbon dioxide absorber of the perching module on it.

It took Pang Xuelin and Watney a full 100 hours of EVA to complete the renovation work.

After that, the two began to slowly transfer various supplies to the rover.

The real trouble is the problem of navigation, compared to the problems with these supplies.

Watney traveled 3,200 kilometers this time, unless he carried the Mars Pathfinder landing module, it would be difficult to use Phobos (Phobos) for accurate navigation, but once the landing module was taken away, Pang Xuelin's side would lose the ability to communicate with the earth, and for a while, the two were in a dilemma.