Reborn in 2011, I am the chief designer of aerospace.

There were no photos, no letters from home. Although he knew Sasha was unmarried, which was one of the criteria for being selected for the Mars mission, he always felt that Sasha must have a partner she cared about on Earth. However, there was nothing.

The only thing Sheng Tianhong could call a "personal item" was a red and yellow mini dollhouse. This toy looked out of place, even absurd, among a pile of highly utilitarian equipment.

Sheng Tianhong carefully placed the dollhouse into the grave, placing it beside the body.

Mira, Song Xingye, Sergei, and finally Han Jing, lined up and took turns scattering a shovel of reddish-brown soil into the grave. Then they silently moved stones and built a simple stone mound.

Sheng Tianhong stood there for a long time, gazing at the stone mound, lost in thought.

This wasn't the absolute worst of it, he could only console himself with that thought. Losing a teammate, dying in an absurd accident, was still within our acceptable limits. At least everyone else was still alive; if this misfortune ended here, we would consider ourselves fortunate.

But there was one thing he dared not utter a single word to the other passengers: deep within Sheng Tianhong's heart, he was being consumed by immense fear.

"We'll make it through this expedition," Sheng Tianhong murmured to himself over and over, as if it were some kind of incantation. "We'll definitely make it through this expedition."

……

Misfortune doesn't seem to be going to stop there.

Song Xingye maintained communication with the mission control center on Earth via video link until Earth completely sank below the Martian horizon.

As if things weren't bad enough, the orbital satellite responsible for signal relay suddenly went on strike at this critical juncture. This satellite had been operating perfectly in Mars orbit for seven years, and of all times, it just had to completely fail at the most critical moment.

Without the relay satellite, they can only establish a weak connection with their home planet during Martian daylight, when Earth is within their field of view.

With no ground support available, Song Xingye had to fight alone, troubleshooting the malfunction until late at night.

When other passengers anxiously inquired about the progress, he either gave them a few perfunctory words or simply ignored them.

After Song Xingye inserted the fiber optic probes into each fuel tank one by one along the pipeline, the images transmitted back cruelly confirmed his worst guess: the Darwin's fuel reserves had been completely exhausted, with not a drop of water left.

While Song Xingye and Sheng Tianhong were busy and overwhelmed inside the spaceship, Han Jing and Mira were outside wielding shovels to level the ground, and then unfolded and inflated to build a hemispherical living pod.

Although they couldn't help the "Darwin," they knew in their hearts that no matter how the situation worsened, this living quarters would be their bottom line for survival.

With the airbags fully inflated and the internal life support system adjusted, they finally had a relatively spacious haven on this desolate planet. This was the first time in seven months of voyage that they could truly enjoy a comfortable sleeping space.

By the evening of the following day, before the other side on Earth could provide a final conclusion, communication had been cut off as the horizon disappeared.

However, based on Song Xingye's on-site testing data and the preliminary analysis by ground engineers, the causes and consequences of the previous terrible disaster have been fully deduced.

Mars, a planet covered in red soil, is rich in sulfur, but due to the lack of an ozone layer, the sun's ultraviolet rays can bombard its surface with impunity.

This high-intensity radiation resulted in the presence of small amounts of highly active sulfur free radicals near the Earth's surface, at concentrations less than one part per million.

Over the seven years of tireless operation of the Darwin's automated fuel production system, this pollution from sulfur free radicals has contaminated all core components, from microelectromechanical sensors used to monitor fuel levels to precision pipelines and seals in the propellant synthesis system.

The contaminated pressure sensor eventually returned false readings, while the microprocessor continued to blindly execute its previous logic, causing the fuel production system to operate at full capacity.

Ultimately, the internal pressure of all the fuel tanks far exceeded the original design safety threshold, and the backup mechanical instruments that should have served as the last line of defense were completely frozen due to condensation and ice buildup, failing to issue even a single alarm.

Even more alarming is that, over a long period of time, those highly reactive sulfur free radicals have caused severe hardening and embrittlement of the polymer seals between the isolated liquid oxygen tank and the propellant production system.

When Sasha tapped the manifold according to standard procedure, the already fragile seals malfunctioned, and high-pressure liquid oxygen immediately gushed out, triggering a chain reaction that caused the seals of adjacent tanks to burst one after another.

Within minutes, all the fuel tanks began to collapse, and the precious fuel accumulated over seven years seeped into the dry Martian sand.

After the Darwin was scrapped, they had no spare return vehicle.

All the crew members on the "Xihe" seemed to be completely trapped on this red planet.

……

While Song Xingye was busy dealing with the malfunction of the "Darwin", Commander Sheng Tianhong instructed the other crew members to continue scientific exploration on the surface of Mars.

He knew that whatever went wrong with the spaceship, letting everyone idly speculate would only worsen the situation.

According to the current mission assignment, his job is to "assist other crew members as needed," but right now, it seems that no one needs his help.

He gradually adapted to the Martian environment. At first, everything seemed extremely unfamiliar. The horizon was unsettlingly close, the rocks were unexpectedly rough, and the sunlight had a glaring, burnt yellow hue.

Dark rocks crisscross the distant mountain ridge, their shadows shifting and changing with the sun, outlining eerie and mottled contours.

But now, all of this is starting to look familiar.

Sergei walked over and stood beside him.

Sergei's spacesuit was a bright turquoise, which contrasted sharply with the yellowish-orange soil on the Martian surface, almost painful to the eyes.

He held a list of scientific observations in his hand, a list of astronomical observation projects jointly compiled by top students from fifty primary schools. However, at this moment, his attention was clearly more focused on Sheng Tianhong.

"Do you have any brothers?" Sergei asked abruptly.

Sheng Tianhong was startled. How did Sergei know that he had just been thinking about his brother?

He initially thought the other person just wanted to chat for a bit to pass the time. Sergei wasn't particularly good at socializing, but at least he was trying.

"Of course," Sheng Tianhong replied cautiously, "I do, I have a brother."

"Just one?"

"Yes, just one, two years older than me." He paused, then asked, "And you?"

"Same here, he's an older brother." Sergei stammered, "No, no, he's a younger brother. How could I say he's an older brother?"

He chuckled self-deprecatingly, "He's a younger brother, still a kid."

Sheng Tianhong had actually expected this, since he had seen the boy's file. However, since the boy had brought up family matters, he was happy to continue the conversation.

Strangely enough, during the long seven-month voyage, when everyone was bored out of their minds, Sergei never mentioned his family, and the other crew members tacitly refrained from asking any questions.

The two walked forward in silence for a while, then Sergei asked again, "What kind of person is he?"

"He's not a bad person," Sheng Tianhong recalled, "but thinking about it carefully, he is indeed a bit domineering. Maybe all older brothers are like that."

"You said it yourself," Sergei replied.

"And what about your brother? How is he?" Sheng Tianhong asked.

Sergei shrugged: "That's fine."

He paused for a moment and took a deep breath.

Sheng Tianhong keenly noticed that the child was trembling slightly. What was wrong? Then, Sergei lowered his voice and asked, "Have you...did you do anything particularly awful to your brother?"

Sheng Tianhong felt her heart skip a beat before resuming its flow. "For example?"

"For example, betraying him? Or making him lie and take the blame for you? Things like that, you know what I mean."

Sheng Tianhong didn't want to delve into this topic. Why would this child suddenly ask about these things?

He looked around, searching for an excuse to escape. Mira had already circled around to the back of the spaceship and was out of sight. Han Jing was squatting next to a rock, working and prying at it to try to collect soil samples from below to test for traces of organic matter that had escaped ultraviolet radiation.

"Excuse me," Sheng Tianhong said. "Han Jing might need some help. Would you mind if I went over there first?"

A hint of disappointment flashed in Sergei's eyes, but he still nodded.

As Sheng Tianhong walked, he fell into deep thought. "This child understands," he thought to himself.

Somehow, Sergei must have sensed something. He's so much like me. Was I being that obvious? Did I exude an aura of guilt? I wonder if anyone else noticed?

……

"This is utter nonsense!" Sergei protested loudly. "Complete nonsense! How could these fuel tanks be empty?"

The group sat around the small folding tray that served as a makeshift conference table.

"Does this even make any sense?" Song Xingye asked rhetorically.

He leaned wearily against the armrest of the driver's seat, his eyes closed. He was clearly severely sleep-deprived, and his face was full of exhaustion.

"It was full when it took off, and it was full when it approached and landed. How come it's empty in the blink of an eye?" Sergei persisted.

"I've already explained it once," Song Xingye said in a hoarse voice, "I don't want to say it a second time."

"There's no point in dwelling on the reasons anymore," Commander Sheng Tianhong interrupted them decisively. "What I need now is a solution."

"What does the emergency response plan say?" Han Jing asked. "Does the plan cover this kind of emergency?"

Sheng Tianhong replied, "The emergency plan instructs us to activate the propellant production equipment on board the Darwin to manufacture new propellant on-site."

"So where did the problem lie?" Han Jing pressed. "Just replace the corroded seals, weld the broken pipes, and restart the equipment. Yes, we might miss the initial launch window, but we can eventually get it done, right?"

"The problem is," Song Xingye said, his eyes still closed, "that we simply can't do it."

Why?

"The operating principle of a propellant processing plant is to use the heat generated by the reactor to synthesize rocket fuel," Song Xingye explained patiently. "After all, this whole process requires a huge amount of energy."

"so what?"

"The energy came from the small closed-cycle nuclear reactor that landed with the Darwin. The reactor converted thermal energy into electrical energy through turbines, which means there are a lot of moving parts inside. The culprit that caused the equipment to malfunction was Martian dust seeping into the reactor's inner shell."

"The bearing is stuck due to sand and dust?" Han Jing realized.

"Wearing will cause the bearing to seize up, leading to engine jamming. High-temperature friction will eventually weld those parts together."

"So you mean we have to replace it?"

Song Xingye interrupted him by raising a finger, "Once the coolant stops circulating, the pipes will burst due to thermal overload. After the coolant leaks out, the temperature of the reactor core will rise uncontrollably, causing the fuel rods to expand and rupture the bushings. In the end, the entire reactor will become a pile of deadly radioactive scrap metal. Want to repair it? We can't even get close to it."

"Chenoty?" Sergei gasped. "You mean, we're sitting right next to a nuclear reactor that's melting down?"

"It's not that exaggerated." Song Xingye spread his hands. "If you're worried about being sprayed in the face with radioactive fumes, then you don't need to worry. But fundamentally, the propellant manufacturing system is completely destroyed and can never be repaired."

"So, the so-called emergency plan has become nothing more than a piece of waste paper?"

"When the contingency plan was designed, no one thought we would need to mess with that nuclear reactor," Song Xingye shrugged. "I guess the designers didn't even consider such an extreme scenario."

A deathly silence fell over the cabin.

"So what do we do now?" Sergei broke the silence. "Are we just going to be trapped here and die? How long will it take for the rescue team from Earth to arrive?"

Sheng Tianhong shook his head: "There won't be any rescue operations organized on Earth."

"But this is a matter of life and death!" Sergei exclaimed urgently. "When the people on Earth find out we're in trouble, they will definitely..."

"I have already reported the situation to headquarters," Sheng Tianhong said in a deep voice. "Right now, we can only rely on ourselves."

"Then what should we do?" Sergei was almost in despair.

Sheng Tianhong nodded: "Isn't this the biggest problem we're facing right now?"

No one spoke anymore.

After a while, Sheng Tianhong spoke again: "Alright, sitting here sighing won't help. Everyone, go back to your posts. Song Xingye, Han Jing, you two think about it carefully and come up with a few backup plans."

"You mean, we're already dead, right?" Sergei muttered to himself. "We're already dead, just a bunch of walking corpses that haven't fallen yet."

No one answered him.