Finding the Mars Pathfinder is only the first step in resuming the communications program.

But the road back was more difficult than Pang Xuelin imagined.

It took him a full seven Martian days to return to the perching module, one more Martian day than he had gone to Chengjia to search for the Mars Pathfinder.

Originally, under normal circumstances, it would not have taken so long, because Pang Xuelin could return the original path along the rutted print, instead of spending a lot of time calculating the guide route.

But on the third day of his return trip, the ninth day after his departure, Pang Xuelin encountered a large-scale sandstorm.

The sand obscured the sun, obscured the ruts, blocked out the sunlight, and even the charging of solar cells became a problem.

Pang Xuelin can only nest inside the rover and maintain the power supply of the rover through RTG.

The sandstorm lasted for two full days before it gradually dissipated, and Pang Xuelin was in the car eating, drinking, and almost collapsed.

It wasn't until two days later in the morning, when a ray of sunlight pierced the sky, that Pang Xuelin realized that he had passed the most difficult moment.

At this time, Pang Xuelin was less than two hundred kilometers away from the perching module.

The rest of the work is simple.

Without the rut marks, Pang Xuelin repositioned with the help of Fubos, as long as he determined the general direction and drove his rover within 40 kilometers of the perching module, he could find the navigation beacon from the perching module.

59th Martian day.

At noon, the white-domed perching module gradually appeared in Pang Xuelin's line of sight, this time the long journey that was originally planned to last eight Martian days, and finally lasted thirteen Martian days finally came to an end.

When entering a radius of 20 kilometers from the perching module, Pang Xuelin contacted Watney through the on-board radio system.

Watney, who was originally worried about Pang Xuelin, put on an EVA spacesuit and went out to greet him.

I haven't seen each other for thirteen days, and the two met again, but they didn't say much, just silently shook their hands and hugged each other, and everything was silent.

Then, the two of them got to work.

The scrapped CO2 filter was thrown aside, the solar panels were re-unfolded and connected to the energy system of the perch, and the contents of the on-board sewage tank were also moved into the perching pod in preparation for the next batch of biofertilizers, and the Sojourner rover moved into the perch, but the landing module was too large to fit in, and the two had to continue to leave the thing outside.

As for the RTG, if the radioactive material inside this thing leaks, it's no joke.

The two of them put it back in the pit where it had been buried, and dug it up the next time they needed it.

Back in the perching module, Watney didn't ask about the Martian Pathfinder for the first time, but smiled: "Pang, I'll show you something good!" ”

"What's good?"

Pang Xuelin was slightly stunned.

"Follow me!"

Watney opened the floodgates between the living pod and the planting pod, and made an inviting gesture.

Pang Xuelin seemed to realize something, and hurriedly walked towards the planting cabin.

Entering the planting cabin, Pang Xuelin immediately smelled a long-lost smell of soil, which was different from when they applied biofertilizer at the beginning, after more than ten days, the soil in the planting cabin had faintly shown a dark brown color similar to the earth's soil, and the humidity in the cabin was much larger than that of the living cabin outside.

But what attracted Pang Xuelin's attention the most was the touch of green reflected in the soil.

And there is more than one stubble, the entire planting cabin, more than 100 square meters of land, is full of small green shoots.

The little green buds are dotted, and on the brown land, it seems to be a ray of hope, breaking through the haze that has covered Pang Xuelin's heart for many days.

Pang Xuelin slowly squatted down, gently brushing the shoots that had just broken through the soil with his hands, a little incredulous, and a little surprised, and his tone choked up involuntarily:

"Watney, we, this is a success?"

Since entering the Martian world, although Pang Xuelin seems calm on the surface, the shadow of death has always lingered in his heart.

It wasn't until he saw the green shoots that he really had any hope of survival.

Watney can completely understand Pang Xuelin's mood, in fact, when he saw the first green shoots, he couldn't control his tears at all, and his performance was even more unbearable than Pang Xuelin.

Watney said: "Pong, I think we don't have to worry about food in the future, at least not for a short time!" ”

"It's a good start, and we're going to ...... It will definitely survive. ”

"Yes, we will live."

……

The two quickly calmed down.

Pang Xuelin found the Mars Pathfinder, but that doesn't mean they can easily communicate with Earth.

First, they had to restore this old antique that landed on Mars forty years ago.

Early the next morning, after a night of repairing, the two officially started work.

"In general, the reason why such unmanned detectors stop working is basically because the dust covering the solar panels is getting thicker and thicker, the temperature drops in winter, and the daylight hours are shortened, resulting in a lack of power supply. When the power of the battery drops to a certain critical point, the heating system of the detector will also be hung up, and then the electronic components will not be able to operate because the temperature is too low, and the control system will also be hung up, even if the solar panel can still provide weak power support, but the lack of electronic components to give a restart command, the system will not be able to restart, and after a long time, the battery system will also lose the ability to store electricity. “

In addition to being a botanist, Watney also works part-time as a mechanical and electrical engineer, and the task of repairing the Mars Pathfinder was naturally entrusted to him, and Pang Xuelin only worked on the sidelines.

Fortunately, the Martian atmosphere is cold and thin, with a gas density of only one percent of Earth's, and even less oxygen and water vapor, which makes the Mars Pathfinder's appearance largely intact.

Pang Xuelin and Watney first inspected the Sojourner unmanned vehicle in the perching cabin, and found that except for the complete damage to the battery, the rest of the parts of the unmanned vehicle were intact, and as long as the power supply was reconnected, it could resume work.

But the landing module outside is not so simple.

Watney wore an EVA spacesuit, circled around the landing module, then pried open the battery compartment, took out the silver-zinc battery inside, and said: "This thing is useless, we have to replace the power supply for it, and there is another problem that is probably more troublesome." ”

"What's the problem?"

"It's winter on Mars, and the maximum temperature in the Asidalia Plain is minus 55 degrees, and the electronic components of the landing module can only be activated above minus 40 degrees," Watney said. We'll have to find a way to heat up the landing module, but it's too big to get through the airlock. ”

Pang Xuelin frowned and said, "Why don't we dig out the RTG again and put it on the edge of the landing capsule to heat it?" ”

Watney shook his head and said: "I'm afraid not, the landing capsule is too big, the RTG is natural heat dissipation, and the power is only 1600 watts, under this temperature condition, it is a little difficult to make the temperature of every electronic component inside the landing module rise to more than minus 40 degrees." ”

"What then?"

Pang Xuelin frowned, trying to recall the scene in the movie, but there didn't seem to be a scene in the movie that explained how Watney dealt with the problem.

The two stared at each other, and after an EVA, the two still had nothing to do, so they had to return to the perching cabin first and talk about it after lunch.

After lunch, Pang Xuelin lay on the bed to rest, and just two minutes after closing his eyes, Pang Xuelin suddenly opened his eyes, patted the mattress and said, "Watney, I have thought of a way." ”

"What's the solution?"

Watney was slightly stunned.

Pang Xuelin laughed and said: "I remember that we only used one of the three auxiliary parachutes for the MDV (Mars landing vehicle) parachute, and even the main parachute was useless, in fact, it was very simple, we only need to build a small tent outside the perching module, and then put the RTG and the landing module together, as long as the tent is sealed, the air inside cannot circulate with the outside world, then with the greenhouse effect, there is no problem at all for the temperature in the tent to rise above minus 40 degrees, and then as long as the landing module is connected to the power supply, the landing module system will be restarted." Wouldn't it be possible to use its own heating system to maintain the temperature? ”

"Pang, you're such a genius!"

Watney's eyes lit up, and he immediately recognized Pang Xuelin's method.

In the afternoon, the two carried out the second EVA, Pang Xuelin moved the RTG back, and Watney continued to cut the MDV's auxiliary parachute, and then set up a small tent in the perching cabin.

Then, the two worked together to move the RTG and the landing module into a tent.

The RTG was so powerful that it took less than an hour for the temperature inside the tent to rise to minus 30 degrees.

Later, Watney went out to reconnect the power supply to the landing module and the Sojourner.

The rest of the work is none of their business.

As soon as the landing module resumes its work, it will actively restore contact with Earth.

Naturally, JPL (Jet Propulsion Laboratory, a NASA agency responsible for developing and managing unmanned space exploration missions for NASA) could not have squatted on the signals of the five-person probe, which had disappeared for forty years, but the next-generation deep space tracking and control network built specifically for the Ares program on Earth would certainly be able to receive the signals of the Mars Pathfinder.

When the time comes, they will naturally notify JPL, and as long as JPL feeds back the signal, the landing module will automatically adjust the position of the signal gain antenna according to the relative position of the earth.

Therefore, Pang Xuelin and Watney only need to judge whether they are connected to Earth based on the change of the gain antenna of the landing module.

"Okay, that's it for today, whether we can restore contact with the earth can only wait for the reaction of the landing module next."

After all the work was done, Pang Xuelin and Watney returned to the perching capsule.

……

Pathfinder Log: SOLO

System sequence initialization is complete......

Time: 00:00:00......

Power loss has been detected, time/date unknown......

Mounting the operating system......

VXWARE OPERATING SYSTEM (C) WIND RIVER SYSTEM STARTS HARDWARE SELF-TEST:

Internal temperature: -34 degrees Celsius

Outside temperature: Inactive

Battery: Full

High Gain: OK

Low Gain: OK

Wind Sensing: Ineffective

Weather Sensing: Inactive

Atmospheric Structure Meter: Ineffective

Imager: OK

Rover Ramp: Inactive

Solar cell A: Inactive

Solar cell B: Inactive

Solar cell C: Ineffective

The hardware check is complete......

Radio Status:

Listen for telemetry ......

Listen for telemetry ......

Listen for telemetry ......

Signal Acquisition ......