With the achievement completed, Lu Yuan's exchange coupon count rose to 68.

A moment later, Jubian also came up in the elevator.

"Everyone's morale is very high right now, Executive Officer!" He walked over to Lu Yuan's side, "Everyone is looking forward to the day when the atmospheric engines are also repaired and the spaceplane truly flies into space!"

"It's good to think that way, but those three engines are severely damaged and basically need to be rebuilt, requiring more rare metals, about fifteen times the amount we have now."

Lu Yuan said.

"Indeed... do we still have to rely on hunting Mechanical Desert Spiders to gather them?"

That would mean hunting nearly 700 of them, which is quite a lot.

Lu Yuan thought for a few seconds.

"No, if everything goes smoothly, not necessarily."

"In the future, the underground cave's function will gradually shift from a raw material source to a practical training ground. In any case, I will figure out how to deal with the rare metal shortage. The fuel issue is more urgent."

Jubian nodded in agreement.

"Yes, Executive Officer. The spaceplane needs to use rocket fuel outside the atmosphere. In the original design, the rocket fuel was liquid hydrogen, and the oxidizer was liquid oxygen. But I suggest changing the fuel to liquid methane. Although the calorific value of methane is slightly lower than that of hydrogen molecules, it is currently very easy to obtain methane from dungeons."

Lu Yuan: "I completely agree."

Currently, there are still over 40 tanks of methane in the cave dungeon that haven't been recovered, totaling about 900 kilograms.

The players are relatively skilled, and there haven't been any accidents involving exploding fuel tanks yet. Otherwise, a gas explosion in the underground space would be no joke and could easily cause a collapse.

Jubian continued, "According to my calculations, a single space mission requires at least 20 tons of high-quality aviation fuel, 30 tons of liquid methane, plus 110 tons of liquid oxygen. In terms of raw materials, this is equivalent to approximately 2500 Mechanical Desert Spiders, plus at least 150,000 kilowatt-hours of electricity."

"Hmm..."

These were two "astronomical figures" that gave Lu Yuan a headache.

It turns out that the meager material gains from fighting monsters cannot replace a complete industrial system at all.

And just be happy with it, the spaceplane only needs a total of 160 tons of propellant to send a body of at least 60 tons out of the atmosphere. On Earth, such a dry mass ratio would be absolute black technology.

This also explains why many planets lost the ability for space travel after the apocalypse.

Even if the knowledge was preserved, these planets would need a very long time to recover the industrial production capacity required for aerospace.

The pace of industrialization must be further accelerated!

"Oh right, Executive Officer, there's one more small matter." Jubian interrupted Lu Yuan's thoughts.

"Hm?"

"The girls in the camp said they want to request some 3D printer capacity to make flour and sugar for the midday meal."

"This can be printed too?"

"Yes, it's just simple organic molecules. As long as the ratio and process are correct, I think it's even possible to print cola, champagne, and cream."

Lu Yuan thought about it and agreed.

The essence of these non-staple foods is chemical substances. Synthesizing them with a 3D printer just consumes a lot of electricity. Occasionally satisfying cravings is fine.

Champagne can be opened.

"Okay, let them do it then."

At noon, Caoyuan, Ye Xing, and Jubian logged on one after another, and everyone prepared lunch together.

"You... even made cookies and cakes? And there's even cola?!"

Seeing the masterpieces of the two female players, Ye Xing could hardly believe his eyes.

Jubian: "Actually, I can also synthesize flour and other things."

Ye Xing: "Come on, forget it~ Why didn't I see you make it before?"

Jubian: "What do you know? Good things are meant to be brought out for celebrations!"

"I also hunted this in that cave in the camp! The scan shows it's non-toxic and edible." Guo Li Cheng displayed a special prey.

It was a mammal that looked a bit like a mole, with sharper claws than a mole, presumably capable of digging sandstone, and about the size of a rabbit.

"Who knows how to prepare this thing?"

"Leave it to me, I can make a soup." Caoyuan stepped forward and took the mole. Having practiced wilderness survival, he knew how to handle animal offal.

If there was anything that could enhance team cohesion more than a big meal, it was the process of everyone preparing the big meal together.

The taste of desserts and such wasn't actually as good as dessert shops on Earth, but thinking that this was the result of their hard work and struggle made the taste in their mouths exceptionally sweet.

The Desert Spider was cooked in three different ways: steamed, stewed, and cola meat patties.

There was also rock rat soup. Being able to eat red meat would significantly increase the camp's habitability.

"Can't eat anymore, can't eat anymore~"

After a delicious meal, Guo Li Cheng asked the question everyone was going to ask.

"Team Leader! What should we do next?"

Lu Yuan suddenly felt that if he could leisurely light a cigar now, it would better fit the temperament of the "Executive Officer" role.

"Next, our camp will undergo rapid construction and expansion, and everyone will have their own task."

He looked at everyone.

"Caoyuan is responsible for planning the camp's defenses."

"Ye Xing is responsible for exploring the surrounding area and lighting up the map first."

"Jubian is mainly responsible for military research, and Xiao Xue is responsible for civilian industry."

"As for Guo Li Cheng, you are responsible for improving the environment within the camp."

"Can we tear down the houses left by the Raiders and rebuild them?" Guo Li Cheng asked, "There's a sour, smelly odor inside that won't go away! And dirty socks are stuffed in the corners!"

"Of course."

Lu Yuan had also smelled that unpleasant odor.

"Tear them all down. Bury the debris somewhere outside, or directly put it into the 3D printer to decompose into raw materials. This camp will be our home for a while, and I hope everyone will take good care of it."

"Understood!"

At the same time, in an underground base built before the apocalypse, the blonde Harte was hunched over a map table, intently staring at a large-scale map.

As the leader of the largest Raiders warband in the Desert, Harte was young, only in his thirties.

Planning the routes for future raids over the next few months was a leisurely pastime for him.

A subordinate walked into the combat command room, clicked his heels together, stood tall, and saluted.

"Report, Lieutenant Colonel Harte! Earlier today, our radar station detected an unknown aerial target!"

Harte didn't look up, continuing to plan the route.

"Did the Apollo company's spaceship go to Oasis City again? Those Celestials have been very active lately."

"No... the target used a radar stealth design, so the position can only be roughly determined, but judging from the general flight path, Oasis City was not on the route."

Harte stopped his work and looked up at his subordinate.

"Oh? That's interesting..."