Rebirth: Starting from Lighting Up the Tech Tree

Chapter 262 Sky No. 3

With only two months left in the countdown to the deadline, the aerospace division has entered a state of war.

Chen Hao moved his cot into his office. He went to bed at 2 a.m. on the first night and was woken up at 5 a.m. An abnormal pressure pulsation had occurred in the liquid hydrogen fuel flow channel of the upper stage. The tolerance of a valve was off by 0.3 millimeters. 0.3 millimeters is negligible in conventional launch missions, but in a nuclear thermal propulsion upper stage for a Mars transfer orbit, it means the propellant flow instability will exceed one-thousandth. One-thousandth of an instability has no impact on the orbital accuracy of an eight-ton payload. But Chen Hao revised the blueprints. He demanded that the valve tolerance control precision be increased by an order of magnitude. The precision of every rocket component must be among the highest in aerospace-grade standards.

The Sky3 Deep Space Edition and the Standard Edition have three major differences. Each difference represents a significant technical challenge.

The upper stage employs nuclear thermal propulsion technology. Instead of generating electricity through fission, it uses the heat from the reactor to heat liquid hydrogen, causing the liquid hydrogen to expand and be ejected at high speed from nozzles. While the thrust is less powerful than a chemical engine, its specific impulse is three times that of a conventional chemical engine. With the same weight of fuel, it delivers three times the thrust for the duration of launch and four times the range. This is currently the only solution within human engineering capabilities capable of sending an eight-ton payload into a Mars transfer orbit. The reactor is cold at launch and only activates after entering low Earth orbit. Activating it on the ground would contaminate the area within a one-kilometer radius of the launch site with radiation. The core safety logic of this solution lies in the fact that the reactor only comes alive in space.

The thermal protection system uses a brand-new carbon phenolic composite material. When the probe enters the Martian atmosphere, the surface temperature will soar to 2,000 degrees Celsius, exceeding the melting point of steel. The carbon phenolic composite will ablate layer by layer at high temperatures, with each layer carrying away heat, keeping the probe's interior at a constant temperature. The material formula was tested more than two hundred times. One piece was fired, the formula was modified, and another piece was fired. Yu Ying personally fired the final seventeen pieces in the deep space laboratory. She said the whole process was like conducting an endless ceramic experiment, with each piece producing a different color.

Deep space communication employs quantum encryption combined with a space-based relay link. The one-way delay between Earth and Mars is approximately sixteen minutes. Sixteen minutes means that the probe cannot wait for ground commands in the event of any emergency. It must autonomously assess, decide, and correct its course. Quantum encryption ensures that no one can intercept or tamper with the telemetry and control signals during these sixteen minutes, but what truly keeps Chen Hao awake at night is the delay, not the security.

The day the entire rocket was assembled was in the evening. The Cangqiong-3 deep-space version stood in the assembly workshop at the Hainan launch site, its light silver color illuminated by searchlights. It stood 62 meters tall, nearly twice the height of Cangqiong-2. Its low Earth orbit payload capacity was 25 tons, and its Earth-Mars transfer orbit payload capacity was 8.2 tons.

The probe, named "Pathfinder," consists of three modules. The orbiter relay module remains in Mars orbit, serving as an extension node of the Sternos constellation. The lander exploration module carries two rovers, one to Valles Marineris and the other to Hellenic Plains. The Origin Detection module is the core of the entire probe, powered by a custom-designed NX-40 series radiation-hardened chip from Fangze, specifically designed to detect and record node energy characteristics.

The probe weighs 7.8 tons. 8.2 minus 7.8 equals a safety margin of 0.4 tons. Every engineer is reducing weight in grams. Replacing a steel screw with titanium alloy saved 17 grams. Using a thinner cable saved 4 grams. The aluminum alloy support underwent topology optimization while maintaining strength; excess material was cut into a honeycomb mesh, weighing 370 grams. All together, it weighs less than 400 grams, but every gram saved means the probe consumes one less unit of fuel during its seven-month journey.

The day Fang Ze installed the NX-40 radiation-hardened chip into the origin detection module, he wrote six words in the test log: "Can last seven months." For Fang Ze, those six words were equivalent to someone else's six-page report.

The day before the final assembly was completed, the China National Space Administration (CNSA) sent a formal letter authorizing 402 as the commercial entity to carry out the Mars exploration mission, with CNSA providing support for the deep space tracking and control network and all necessary international coordination.

That same afternoon, a retired expert from the China National Space Administration called Zuo Cheng's office. He spoke a few words on the phone, his voice aged but clear.

"When I was young, I participated in the development of the first Dongfanghong satellite. Later, I watched Yang Liwei fly into space. Then I watched Chang'e-1 go to the moon. My generation sent satellites into space and astronauts to the space station. But we never made it to Mars."

He paused for a moment.

"You go in our place."

After hanging up the phone, Zuo Cheng sat in his office for a long time.

On the evening the arrow was fully assembled, Zuo Cheng signed his name on the arrow body. The black marker strokes were neat and precise. Then he handed the marker to Yu Ying.

Yu Ying didn't sign her name. She drew an arrow. The arrow pointed towards Mars. Next to the arrow, she wrote two words.

say hello.

"It's not about conquering," she said. "It's about greeting an ancestor from four billion years ago."

Seven days before launch, the Pathfinder spacecraft and the Sky3 rocket successfully docked. The paint shop painted four national flags onto the rocket's fairing: the five-starred red flag of the China National Space Administration, the blue stars and stripes of NASA, the dark blue ring of ESA, and the sun flag of JAXA. For the first time in human history, the logos of four space agencies appeared simultaneously on a deep-space rocket.

With only forty hours left before the launch window opened, Chen Hao discovered a micro-crack in the shielding of a sensor cable during the final full-rocket inspection. The crack didn't affect functionality, but it reduced the redundancy from twice to half. Chen Hao ordered a replacement, and everyone worked through the night to remove the cable from the rocket and replace it. It wasn't because of the high risk, but because nothing could be repaired on the Earth-Mars transfer trajectory.

The lights in Building 402 were still on in the early hours of the morning. From the Aerospace Division to the Quantum Computing Division to the Satellite Control Center, behind every lit window was a group of people pushing the boundaries of humanity outwards.