Titanium Skeleton

With the basic framework chosen, next came the choice of skeletal material.

"Should I choose calcium?"

Calcium was relatively light, and the straight-shelled nautilus being used as the design template also had calcium as the main component of its material.

If he chose calcium directly, the number of matters he had to deal with would suddenly drop by a lot.

A skeletal system was not something that could be completed overnight. He had to consider the new material's density, chemical reactivity, difficulty of acquisition, and so on. If calcium was used as the skeletal material, those data could actually be applied directly to the design, saving him a great deal of trouble in gathering parameters all over again.

After pondering for a while, Huo Gu dismissed the idea.

"No, calcium can't meet my expectations. Calcium is too low in hardness to serve as bone. If I want to guarantee protection, I'll have to thicken the shell, but in that case, not only will it take up space, its 'lighter material' quality will become completely meaningless."

Calcium's Mohs hardness was 1.75, while skin's Mohs hardness was 1.5. With that comparison, one could very intuitively see just how "soft" calcium really was.

Back then, why had Earth's organisms chosen calcium as bone?

There were many reasons, but Huo Gu mainly leaned toward the explanation that, in terms of how easy the material was to obtain, it was what ultimately caused Earth's organisms to choose calcium as a skeletal material.

In Earth's early environment, calcium carbonate existed in large quantities. Large amounts of calcium carbonate could be found in things like calcite and limestone, and in terms of preparation, calcium carbonate very easily separated out calcium.

However, what Huo Gu wanted was performance. What he wanted was a sturdy and sufficiently light material. He could rely on the cells to achieve molecular-level material processing. He did not dare say much about anything else, but when it came to preparing elements, he could already leave those chemical plants on Earth several streets behind. He did not need to worry about obtaining materials.

This could be seen from the various elemental substances Huo Gu had stockpiled.

"But if it's iron, won't it be a little too heavy?"

Such an image surfaced in Huo Gu's mind—a newly designed cell cluster, resembling a straight-shelled nautilus in appearance, drifted through the sea, then drew closer and closer to the seabed, until in the end it could only move through the water while hugging the ocean floor.

"No, no, no! What am I thinking? That won't do!"

"I need a very light material. It has to be light enough..."

"In other words, the density has to be low. If the density is high, then the mass per unit of space will naturally be high as well."

This truly exceeded Huo Gu's scope of knowledge. His old profession was archaeological excavation, and the fields of knowledge he was proficient in were geology and biology. As for mathematics, physics, and chemistry, he had only reached the high school level.

And that was still being rather optimistic. Before Huo Gu had become what he was now, he had already been an elderly man nearing sixty. Decades had passed since his high school days, and it was hard to say how much he still remembered.

All of a sudden, Huo Gu recalled what had happened at the International Space Center. An old friend who worked there had once bragged to him about a metal—titanium.

"Titanium. Back then, that guy Old Tang praised this metal to the skies in front of me, even saying something about how Earth's first generation of space battleships would definitely use this metal too..."

"Tch, wasn't he afraid of biting his tongue with a wind that strong? We didn't even have a space elevator yet, and the International Space Station was just a tiny grain of rice. Space battleships? They hadn't even touched the edge of one, yet he only knew how to brag in front of an outsider like me. Even a Mars excavation needed manned spaceflight to pull off..."

At this thought, Huo Gu's resentment was still hard to dispel. Back then, it was precisely because he was old, and his aged bones could not withstand the reaction force of a rocket launch, that he had been reduced to taking part in remote command work at the International Space Center.

Since you people had even already imagined space battleships, then hurry up and build the space elevator! I fucking wanted to personally take part in the Mars excavation!—If there had been a space elevator at that time, Huo Gu's elderly body would no longer have been an obstacle to his going to Mars.

After venting for a while, Huo Gu also returned to his original calm and began to examine the metal "titanium."

"As an aerospace metal, its high-temperature resistance and pressure resistance should go without saying..."

"Then there's its mass. Since it was still rocket transport, materials would develop as much as possible in the 'light' direction, which just happens to fit my current needs."

"Mm, then I'll decide on 'titanium.'"

However, Huo Gu did not understand this metal very well. After all, he was an outsider who only knew how to do archaeological excavation work, and in both industry and aerospace materials, he only had a smattering of knowledge.

But that did not matter. If he did not understand, he could learn. With a physical sample present, and one he could experiment on however he wanted at that, it was just that feeling things out would cost some time.

Having selected the skeletal material, Huo Gu began to acquire information about "titanium."

First of all, he had to determine whether this metal could exist stably on the planet Huo Gu was currently on.

This was very important. Even if titanium's properties in every aspect were excellent, if it was placed in an environment that made it react extremely easily, then it would be a waste, and it could not be made into any sort of shell that could provide protection.

The method Huo Gu adopted was extremely simple and crude. He squeezed a small portion of the stored titanium metal out of the cavity and into the ocean, then observed it with the naked eyes on the root system.

The titanium metal in the ocean was wrapped up by a rootlet. While preventing it from being washed away by the current, the rootlet was also responsible for sensing changes in temperature. Any chemical reaction would be accompanied by the physical change of heat absorption or heat release.

After confirming that there were no changes at all, Huo Gu retrieved this portion of titanium metal and created a cavity specifically for experiments on a section of the main root at the seabed.

The retrieved titanium metal was placed into that cavity. Following the periodic table, Huo Gu transported elements one by one into the experimental cavity, from hydrogen, helium, lithium, boron... After confirming there was no reaction, he drew the element back and injected a new one, repeating the process over and over.

After the aqueous solution environment was finished, he would try using an air environment to repeat the experiment all over again, seeing the changes in an air environment... Then came all kinds of pure gas experiments, checking the changes of titanium metal in such environments... After that, there were the changes in strongly acidic or strongly alkaline waters...

To make use of titanium metal, he had to have a comprehensive understanding of titanium metal. None of these experiments could be omitted or handled carelessly. They had to be conducted seriously and practically, in order to obtain accurate data.

Of course, other aspects naturally were not neglected either. Step-by-step experimentation was a tedious and extremely time-consuming matter, so Huo Gu chose to solve it in parallel with the other issues in the new design.

What came next was design: making reasonable use of every inch of space inside the conical shell.

Huo Gu had not forgotten the original design standard—to design an individual capable of surviving under the super tide!