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

"Power comes first."

As soon as Song Xingye started to speak, President Liang crossed his arms, adopting a "no discussion" stance:

"For a propulsion system, every gram of fuel is a lifeline. The Hohmann transfer window on Mars is only a little over twenty days long. Launch delays, orbital deviations, mid-course corrections... which of these doesn't require fuel as a safety net? If you want to cut fuel, you're asking for the designers' lives—no way!"

"Hey... let me explain first..."

Song Xingye said in a serious tone:

"I know about your little tricks with the propulsion system. It's just to ensure that there's a chance to launch every day during the launch window, so you fill the fuel according to the 'worst-case' conditions."

"But in my opinion, this is a typical example of 'laziness margin,' using excessive fuel to mask uncertainties in calculations and planning, which I think is inappropriate."

Mr. Liang raised an eyebrow, his eyes sharpening. "Oh? What brilliant idea do you have?"

"I think we could look to NASA's mission experience. In traditional orbital design, all corrective maneuvers are designed to pull the probe back to a predetermined 'standard orbit.' This means that if there's a deviation during launch or orbit insertion, a lot of fuel has to be consumed to correct the error, right?"

"That's right."

"But I think that if a deviation occurs, instead of correcting the error and returning to the original standard trajectory, we can use a computer to recalculate an optimal path to Mars from the current state, which can offset the fuel consumption."

President Liang shook his head decisively: "The risk is too great. What if the calculations on the satellite are wrong? That's hundreds of millions of kilometers of deep space; there's no chance for you to start over."

"Then we'll compress the launch window from 26 days to 14 days, eliminating the few extreme windows with the highest energy requirements."

Song Xingye said confidently, "Trading computing power for fuel, and precision for weight—President Liang, this is a worthwhile deal!"

Mr. Liang remained silent for a long time.

He tried to find a point of rebuttal, but the logical loop was perfectly tight.

Finally, the old man snorted and waved his hand: "You pass, kid. As for the power system, I'll cut it by 10 kilograms, not a gram more!"

Song Xingye smiled. He should have succeeded in persuading him, right?

The first battle was won.

Then, he turned his attention to Lei Gong.

Lei shook his head vigorously: "Don't try to take advantage of me. Mass is stiffness, and stiffness is survival. The overload during rocket takeoff is 6G. Random vibrations and noise can shake the probe apart, so the structural weight cannot be reduced."

However, Song Xingye didn't buy it at all and continued:

"Master Lei, we can't just take it by force, but we can use 'skill' to overcome it."

"I know that structural system standards have backdoors. If we can provide high-confidence destructive testing data to prove that the structural strength overflows, could the standards be lowered?"

"Also, why use aluminum honeycomb panels for the electronic equipment boards and instrument bay decks? Replacing them all with carbon fiber would reduce the weight by half..."

Lei Gong glared at him: "Nonsense! Carbon fiber has such poor thermal conductivity, how can you expect to dissipate the heat from hundreds of watts of electronic equipment? Are you trying to roast sweet potatoes in space?"

Song Xingye remained calm and composed. "There's a type of graphite film abroad with high thermal conductivity, four times that of aluminum alloy, but it's a bit pricey... However, I think it's worth a try. Otherwise, if no one is willing to compromise, how can the probe be launched?"

Lei Gong pondered for a few seconds, then his tense expression finally relaxed. "Alright, you pass. I'll reduce it by 15 kilograms for you, not a gram more."

They captured two cities in quick succession.

Song Xingye didn't stop walking and walked over to Engineer Lin: "Engineer Lin, for the sake of the bigger picture, how about cutting a few wires?"

Engineer Lin remained unmoved: "Redundancy is the soul of aerospace. Every signal from the probe needs to be double-backed up. How can you expect me to cut it?"

Song Xingye flipped through the booklet in his hand and said:

"I think some non-critical data, such as temperature sensors and strain gauges, don't need dual backups. And what about the more than 300 health monitoring sensors scattered throughout the detectors? How many cables are being wasted?"

"I boldly suggest replacing these with LED optical communication or short-range radio frequency for data transmission. I don't think it's difficult to achieve this technology; some skilled individuals could even build it by hand."

Song Xingye's eyes were burning.

"If the replacement is successful, it will save a lot of copper and connectors, and the cable system will be 100 to 20 kilograms lighter, right?"

Engineer Lin gave him a deep look and smiled, "Alright, we've already said all this, if I object again, it would be deliberately making things difficult. I'll do you a favor and reduce the weight by 20 kilograms, okay?"

"Thank you, Mr. Lei!"

Song Xingye grinned and finally stood in front of Engineer Chen. "There's only 5 kilograms of excess weight left. The load system shouldn't be too difficult, right? Just squeeze it out."

Engineer Chen retorted confidently, "Squeeze? Do you think this is like squeezing toothpaste? Every payload on the Mars probe has undergone years, even decades, of research and development, embodying the hard work of countless scientists. Do you think it's something to be taken to Mars to drop lead balls?"

Song Xingye flipped through the booklet and nodded in deep agreement, "Indeed, high-resolution cameras, spectrometers, meteorological instruments, and surface radars are all quite important."

"Exactly. Which one are you talking about cutting? A lifetime of hard work, all undone by a single sentence from you? Do you believe those professors will come after you with knives tomorrow?"

"radar."

Song Xingye pointed out incisively, "The dual-polarization detection of surface radar requires two sets of antennas. I think it can be downgraded to single-polarization. While retaining one antenna, we can cut off the radar's data processing unit and move it to the detector's main computer."

"Kid, do you know what the consequences of this will be?"

"Of course I know that when the radar is turned on in the future, the main computer will be fully loaded and unable to perform high-bitrate communication or complex tasks, so it can only work during off-peak hours."

Song Xingye shrugged: "But I think that just two hours a day on the main computer is enough. As long as we fly a few more times, the data can always be recovered! By trading time for space, we can save those 5 kilograms, right?"

Engineer Chen stared at Song Xingye for a long time, then suddenly smiled, "Not bad, you're quite adaptable. I'll give you the 5 kilograms of extra weight."

After finishing his rounds, Song Xingye closed the file in his hand and gently placed it on the table.

"I guess I've passed the test?"

Mr. Liang smiled and said, "Not only did you pass, but you far exceeded my expectations. Your level of knowledge is completely unlike that of a PhD student your age. Did you work on Mars rovers before?"

Song Xingye hadn't expected such high praise; he had simply summarized his experience based on cases he had encountered in his previous life.

He shook his head upon hearing this, "I haven't done any related research... I just read a lot of miscellaneous books and do some random thinking. I hope you teachers don't think I'm just showing off my limited knowledge..."

"Heh, if every student could show off like you, we old folks would have retired long ago and could be enjoying our golden years!"

Engineer Lei, Engineer Lin, and Engineer Chen all laughed.

"Dongguo Aerospace has promising successors," President Liang remarked, then his smile faded and he said seriously:

"Given your excellent performance, here's a special reward for you. You don't need to answer both of the next two questions. After reading them, just choose one that you feel you're good at."

Song Xingye was somewhat flattered: "There's such a good thing?"

"Of course, this is a preferential treatment for the strong." President Liang pointed to the remaining two documents. "Take a look, which one do you want to choose?"

So Song Xingye went back to his seat and opened the remaining two booklets.

The title of the first booklet is "Emergency Response in the Abacus Era: Manual Ballistic Reconstruction and Interception Algorithms".

The background of the question is an extreme combat environment that occurs after the world suffers a full-band electromagnetic pulse attack, in which silicon-based computing power is completely reduced to zero, and all software that relies on phased array radar, high-performance computer clusters and automated trajectory prediction is instantly paralyzed.

In such a "black swan event," the analysis of orbital mechanics will trace back to the fundamental methods established by Gauss, Laplace, and Gibbs in the 18th and 19th centuries.

The question states that an out-of-control reconnaissance satellite is experiencing uncontrolled orbital decay. The task is to manually calculate and deduce the satellite's decay trajectory and determine the unique kinetic interception window.

Song Xingye felt a chill run down his spine; this question clearly tested one's mathematical instincts when free from computer assistance.

Modern orbital mechanics relies primarily on numerical integration, which demands high computing power from computers; whereas in the 19th century, it relied purely on human computational power, thus necessitating a return to analytic geometry.

That formula is just a matter of doing tons of practice problems.

This is too brain-taxing!

He shook his head and shifted his gaze to the second book.

The title of this book is quite interesting; it's probably inspired by the Hollywood movie "The Martian."

"Construction of an Emergency Life Support System Based on Destroyed Spacecraft Debris in the Extreme Environment of the Martian Surface: Oxygen Generation from Electronic Waste!"

The problem involves an extreme survival crisis on the surface of Mars where an oxygen generator suddenly malfunctions, requiring the generation of oxygen from existing space debris, including solar panels, a malfunctioning rover, and several wires.

Song Xingye slapped his forehead, trying to recall how the unfortunate protagonist in "The Martian" produced oxygen.

Just as he was pondering this, Mr. Liang across from him tapped on the table, interrupting his thoughts:

"Have you reviewed both questions? They're about the same difficulty level; one tests theoretical limits, the other tests engineering quick thinking. Have you decided which one to choose?"