I live in the Martian wilderness!

Gu Yu passed through the airlock and headed straight for the "solid waste treatment unit" in the corner of the command cabin.

This machine has been working silently for the past two weeks, not only recycling water but also subjecting all excrement to high-temperature aerobic digestion, vacuum drying, and ultraviolet sterilization.

He reached down and pulled open the bottom recycling compartment, taking out a tightly sealed metal can.

"Smack."

The sealed container was opened, and it was filled with grayish-white, dry crystalline powder.

There was no strange smell as I had imagined; only a chemical smell, similar to a mixture of ammonia and minerals.

"Xuan, check the dosage. We have 1.5 tons of water now, is the organic fertilizer in this tank enough?"

"Stoichiometric calculations are in progress..."

Xuanjian immediately projected a set of mathematical formulas onto the HUD.

"Reporting to the Colonel, after weighing, your current reserves total 430 grams of urea powder and mineral crystals."

「根据化学式CO(NH2)2CO(NH2)2计算，尿素含氮量约为46.7%。折合纯氮元素，您手中的储备量约为200克。」

"The Lunar Palace-III formula requires a high nitrogen concentration to support the high-density proliferation of spirulina. At least 600 grams of pure nitrogen are needed for 1.5 tons of water."

"Conclusion: Your 'personal contribution' of nitrogen fertilizer can only meet 33% of the total demand. The remaining shortfall is as high as 400 grams of pure nitrogen."

"If the nitrogen supply is not replenished, this batch of spirulina will face severe 'nitrogen hunger' after the nitrogen source is depleted, which will manifest as stunted growth, yellowing of the algae, and a sharp drop in protein content."

Gu Yu looked at the somewhat shabby-looking jar of powder in his hand, shook his head helplessly, and put the lid on.

"I knew it." He sighed. "It's a pipe dream to think that I can support a biological factory on my own. The law of conservation of energy still needs to be respected."

He put the sealed container back in its place and turned to walk towards the airlock: "Fortunately, we still have other options. Let's go see the results of Shen Gong's overtime work last night."

……

A few minutes later, Gu Yu returned to the Sky Shuttle outside the shelter.

On the side of the Shenggong additive manufacturing module, there is a "chemical extraction and waste discharge outlet" that is not usually used.

At this moment, a heavy collection bag made of high-strength polyethylene is hanging there.

Gu Yu stepped forward, took off the bag, and found it extremely heavy. It was filled with a reddish-brown, slightly damp, coarse powder.

It looks like soil, but it's the "essence" refined through a complex chemical process.

"Xuan, confirm the ingredients. This is the key to filling the gap."

"Understood, Lieutenant Colonel. Retrieving the [Mars regolith in-situ leaching record]."

Xuanjian showed Gu Yu a video of an accelerated chemical process:

In the video, the Tissot tirelessly swings its mechanical arm, filling the entire surface of Martian weathered soil into the specially made high-temperature and high-pressure reactor of the "Divine Works" module.

Subsequently, a cutting-edge technology originating from the Institute of Process Engineering, Chinese Academy of Sciences—the "subcritical hydrothermal leaching and bipolar membrane electrodialysis coupling process"—began to operate at full power.

Under a pressure of 2.5 MPa, the injected high-temperature pure water is used as a solvent.

Then, the nitrates, sulfates, and perchlorates in the Martian soil were forcibly stripped off and mixed into a turbid "mother liquor".

Next comes the precision sieving at the microscopic level.

Multi-stage ion exchange resins precisely capture and remove highly toxic perchlorate ions, relentlessly discharging them into the waste liquid tank.

The precious nitrate and phosphate ions are retained and enriched layer by layer by the electrodialysis membrane, and finally condense into crystals in the vacuum evaporation chamber.

Ultimately, it was concentrated into the essence weighing about 5 kilograms in Gu Yu's hand.

[Composition confirmed: The main components are magnesium nitrate and calcium nitrate (inorganic nitrogen sources), with small amounts of phosphates and iron salts as byproducts.]

"This is the compound fertilizer we wanted." Gu Yu nodded in satisfaction. "By mixing organic nitrogen and inorganic nitrogen together, this 'feast' is complete."

……

Back in the backyard, Gu Yu didn't rush to put food into the pond.

He found a large polyethylene mixing tank in the open space and filled it halfway with 32-degree warm water from the pool.

"Now, let's start preparing the soup."

Like a meticulous chemist, Gu Yu put on goggles and rubber gloves. He opened the sealed jar and poured all the grayish-white urea powder inside into the bucket.

"Xuan, record the organic nitrogen source and add it."

Then they opened the reddish-brown bag and precisely weighed out 3.5 kilograms of soil-extracted salt using an electronic scale.

"These are inorganic nitrogen sources, plus phosphorus, potassium, magnesium... and most importantly, iron."

Gu Yu watched as the red powder slowly sank into the water. "Xuan, you know, right? Mars is red because of iron oxide."

"Spirulina needs a lot of iron to synthesize chlorophyll and phycocyanin. The abundance of iron in the formula developed by Chinese scientists has been specially increased because Mars has no shortage of iron."

"Yes, Lieutenant Colonel. But you need to add one last thing."

"clear."

Gu Yu took out a packet of white powder from the toolbox. It was sodium bicarbonate (baking soda), a chemical reserve from cargo hold number two.

Xuanjian added, "This is also the essence of the Moon Palace formula. By adding baking soda to build a stable carbonate buffer system, the pH value can be locked at around 9.2."

"This is both the alkaline environment that spirulina prefers and a no-go zone for most other bacteria; it's a biological moat."

"Whoosh—"

The addition of baking soda did not cause a violent reaction in the bucket; it only became slightly cloudy.

Gu Yu picked up a long carbon stirring rod and began stirring the contents of the bucket frantically.

"Sizzle sizzle..."

As stirring continued, the originally clear, warm water rapidly changed color. The grayish-white urea dissolved, and the reddish-brown mineral salts dispersed.

A few minutes later, a murky liquid with a faint rusty red and gray hue appeared in the bucket. It didn't look appetizing and even resembled muddy water.

But in Gu Yu's eyes, this was a bucket of priceless "life matrix".

"Solubility test".

"Saturation is 90%, all solutes have formed a homogeneous solution," Xuanjian reported.

"That's right." Gu Yu carried the bucket of concentrated liquid, a blend of Chinese aerospace wisdom and Martian minerals, to the edge of the runway pool.

"Xuan, turn the aeration pump up a bit and use the air bubbles to stir it."

"Understood, increase aeration power to 50%."

The pool water instantly boiled, with bubbles churning everywhere.

"The food is served!"

Gu Yu held the bucket by the rim with both hands and poured the murky nutrient solution evenly into the flowing pool water, following the direction of the water flow.

"Splash—"

The moment the concentrate is added to water, it spreads rapidly, just like ink being dropped into a clear spring.

Under the combined action of water flow and air bubbles, the murky red and gray hue was diluted within minutes and evenly distributed throughout the 1.5-ton body of water.

The originally crystal-clear pure water has undergone a visibly qualitative change.

It was no longer transparent, but instead took on a pale yellow hue—a sign that it was rich in various mineral ions. It was no longer stagnant water, but had become a cradle for life.

"Xuan, retrieve the data from the multi-parameter water quality analyzer."

Gu Yu plunged the sensor probe deep into the water, his eyes fixed on the readings on the HUD.

[TDS (Total Dissolved Solids): 1850 ppm. Meets the standard.]

pH value: 9.2 (slightly alkaline). Perfect range.

Nitrogen concentration: 400 mg/L (sufficient).

Phosphorus concentration: 45 mg/L (sufficient).

Trace elements (iron, magnesium, manganese): Abundant peak values ​​were detected.

"Perfect……"

Gu Yu looked at the pool of water that finally had nutrients and breathed a long sigh of relief.

"Water temperature 32 degrees Celsius, pH 9.2, Lunar Palace-III formula prepared. Plenty of food and drinks available at a suitable temperature."

"Now, everything is ready, except for the final push. Let's go, Xuan. Let's go and bring out our spark!"