Huntian: StarTrace · published
In our previous dev blog, we started with the H–R diagram and worked our way to the fireball storm, gradually piecing together the sky of Lexing. But the sky is only the stage. What truly gives players something to do beneath that sky is the path under their feet——a journey from the most primitive forms of survival all the way to controlled nuclear fusion.
That path is the tech tree.
The smallest unit of our tech tree is the tech node. Each tech node contains a name, description, category, required materials, unlockable items, unlockable skills, and prerequisite nodes.
Why use individual “nodes” instead of a single continuous progression bar?
The core narrative of our game is rebuilding civilization. Civilization does not return along a perfectly smooth curve. Instead, it progresses through a series of pivotal moments—from mastering fire and domesticating crops to inventing the steam engine and eventually harnessing nuclear fusion. Each one represents a distinct leap in human understanding. Each node represents an irreversible leap in understanding.
Because the system uses discrete nodes rather than one continuous progression bar, every unlock gives the player a clear sense of progress: I have advanced. This rhythm of progression mirrors the way human civilization itself has advanced, allowing players to feel how technological revolutions are built on long periods of accumulation, yet often emerge through sudden leaps at critical turning points.
But nodes alone are not enough. Without meaningful connections between them, the system would be little more than a scattered collection of isolated points. That is why we introduced prerequisite tech nodes. A tech node can have multiple prerequisites, and all of them must be unlocked before the next node becomes available. Together, these relationships form a directed acyclic graph. What the player sees is not simply a list, but an interconnected tree of technological development.
Tech nodes are divided into three categories:
Category
Name
Design Purpose
1
Energy
Main progression · Drives the ending
2
Nine-Tier Needs
Survival progression · Drives everyday experience
3
Other Branches
Exploration expansion · Drives player freedom
Today, we are mainly going to talk about the Energy branch.
Energy is one way of measuring the level of a civilization. The Kardashev scale classifies civilizations according to their ability to harness energy—a Type I civilization can utilize the energy available on its planet, while a Type II civilization can harness the energy of its star.
In our game, humanity begins at what is effectively a “Type 0” stage, starting from the most primitive forms of survival and gradually advancing toward controlled nuclear fusion. This Energy branch serves as the player’s main progression path throughout the journey.
The branch can be summarized through four major stages, each representing a leap in the way energy is understood and used:
Fire → Steam → New Energy → Controlled Nuclear Fusion
Fire is one of the first external sources of energy that humans learned to actively control and use to reshape their surroundings, an achievement that marks the beginning of human civilization.
Cooking food can destroy certain toxins and pathogens and greatly improve digestibility and nutrient absorption. It may also have played an important role in later human physiological and neurological development. Heat expanded the range of climates humans could survive in, allowing them to move beyond warmer regions. Firelight helped deter predators and made the night safer. Fire made pottery possible, and later metallurgy, opening the door to craftsmanship and allowing humans to turn stone, earth, and metal into tools of their own making. The hearth brought people together, creating opportunities for communication, language, and early culture. For the first time, humanity began to understand that fire could be deliberately ignited, preserved, and passed on, a realization that established the very idea that external energy could be harnessed.
Fire meant that humans no longer had to rely solely on their own bodies. For the first time, humanity tapped into the chemical energy stored in nature, setting in motion the long chain of energy development that followed.
You stand beside a firepit built from the wood you have just gathered, holding a Glimmer Extractor in your hands. A beam shoots out and ignites the fire. Here, on a moon countless light-years from Earth, humanity learns one of its oldest skills all over again: how to make fire.
Steam was one of the first ways humanity learned to continuously convert heat into mechanical power. It marks the transition from using heat directly to transforming energy into motion.
The heat from a fire naturally disperses into the surrounding environment, making it difficult to use that heat directly and continuously to drive machinery. The steam engine solved a fundamental problem: trap the heat, and make it push in one direction. When water is heated into steam, its volume expands dramatically—by roughly 1,700 times under typical conditions. Confined within pipes and cylinders, that expansion is converted into controlled mechanical force. For the first time, humanity could direct energy in a consistent way: boil water, push a piston, turn a wheel, and drive an entire production line.
The significance of steam goes far beyond the machinery itself. It introduced the fundamental logic of industrialization: energy could be converted, transmitted, and used at scale. The coal burned inside a steam engine was no longer simply fuel for warmth, but a source of power for machines. This shift from thinking in terms of fuel to thinking in terms of power was one of the first major leaps in humanity’s understanding of energy. With steam, humanity truly began to understand what mechanical power meant.
The first time a burst of steam from the engine scalds your hand, you instinctively pull back, then you freeze. Steam. Pressure. Power. You run a copper pipe from the exhaust into a condenser filled with ice-cold water; the piston begins to move back and forth under the force of the steam. And then you hear it—the first roar of machinery on this moon.
Humanity on Earth took thousands upon thousands of years to go from fire to steam. You did it in less than a season.
New energy represents another major step in the way civilization harnesses power: from relying on fuel to actively developing a wider range of natural energy sources, including wind, water, and light.
Fire and early steam power both depended on burning something—wood, coal, oil—to release the chemical energy stored in fuel as heat. This kind of energy use is ultimately constrained by fuel supply: how much fuel you have determines how much energy you get. New energy begins to break away from that limitation.
Faraday’s law of electromagnetic induction tells us that when a conductor moves through a magnetic field, an electromotive force can be induced. With mechanical power from wind, water, or a steam engine, together with copper coils and magnets, you can build even the most basic generator. Wind, water, or steam sets the coil spinning inside the magnetic field, and the current begins to flow.
At the same time, look up at the sky. Two stars take turns illuminating Lexing. The F-type main-sequence star has a surface temperature of around 6,300 K and produces strong ultraviolet radiation, while the K-type red giant casts a warmer, redder light. Together, they give Lexing unusually long periods of daylight, allowing solar panels to remain active for much of the day. This gives Lexing more favorable conditions for harnessing solar energy than those on Earth.
You wind copper wire into a coil and obtain a permanent magnet, then set them up beside the waterwheel, the wind turbine, and the steam engine. The coil begins to spin within the magnetic field. The moment the light comes on, you cry. Not because you are moved—though perhaps you are. Because of the light. Real, stable light!
Finally, you no longer have to worry about running out of electricity. But electricity is not the end.
Nuclear fusion is one of the most fundamental sources of energy in the universe. The stars themselves are powered by fusion. Under extreme temperatures and pressures, isotopes of hydrogen can overcome the Coulomb repulsion between their nuclei, fuse into helium, and release enormous amounts of energy. Humanity spent decades on Earth pursuing controlled nuclear fusion without fully achieving it. But on Lexing, you have something Earth never had: the remnants of the Arkship.
Fusion requires three things.
The first is temperature. Hundreds of millions of degrees. No material can directly withstand temperatures like these, so the plasma must be confined using magnetic fields. Superconducting coils generate powerful magnetic fields that suspend the plasma in a vacuum and keep it from touching the surrounding walls. This is the basic principle behind a tokamak: a magnetic bottle containing a miniature star.
The second is fuel. Deuterium and tritium. Deuterium can be extracted from water. Electrolysis can be used to enrich and separate deuterium from ordinary water. Tritium can be bred from lithium inside the reactor system.
The third is ignition. A fusion reaction requires an enormous initial input of energy to begin. Much like an engine needs a spark to start, a fusion reactor needs its own “spark plug.” That spark plug is the Fusion Igniter, a core component recovered from Huntian.
The Fusion Igniter is not something you can manufacture yourself. It is a remnant of humanity’s most advanced technology, carried aboard the expedition before the crash and protected beneath layers of armor. When the station broke apart, the igniter fell with the core wreckage of the Ring of Power. Throughout the game, you explore the scattered impact sites of the Ring of Power, collect fragments, and decipher what remains of its damaged technology.
You spend one season bringing the igniter back to your base. Then another season building the magnetic confinement coils. The deuterium has already been waiting in its storage tanks for a long time.
You install the igniter. Activate magnetic confinement. The plasma begins to circulate through the vacuum chamber. Then, you press the ignition switch.
A miniature star is born inside the reactor.
One hundred million degrees. Hotter than either of the real stars hanging above Lexing. Held inside a magnetic bottle, it burns quietly. Hydrogen becomes helium. Mass becomes energy. And that energy becomes electricity.
You connect the artificial stellar engine to the reactor. The engine exhaust begins to glow. The propulsion system of the Arkship—one of the oldest surviving human creations on this moon—awakens once again in your hands.
It is time to go Home.
Taken together, the four stages of the Energy branch form a hidden narrative arc:
from survival, to active use, to deeper exploitation, to transcendence of the environment itself.
Progress along the Energy branch is not simply about increasing power output. It reflects a changing relationship between the player and Lexing. At the beginning, you are adapting to the environment. By the end, you are learning to move beyond its limits.
The player's journey on Lexing—beginning with the remnants of the Arkship, passing through the wreckage of the Ring of Power, and eventually returning to the Arkship—is built around recovering and repurposing what was left behind by the crash. You are a survivor of a crash.
Everything you have is part of that fallen legacy. And eventually, you use those same remnants to reignite the Arkship’s engines and rise from the surface once again.
That is the meaning of the Energy branch: It starts with a crash and ends with a launch.