218: Chapter 218 Purchasing the Next Piece of Information

The qingqiong-1 mission hall was much older than the central discussion room.

The two rows of consoles had been in use for seven years, and the keycaps of several frequently used keys had worn down to a glossy finish; the main screen on the wall still retained the last frame of valid telemetry from the day the satellite lost contact.

State of charge of the storage battery: thirty-one percent.

Angular velocity of the celestial body: zero point one nine degrees per second.

Main computer machine A working, machine B in cold standby.

The end of the frame stopped at fourteen seventeen and forty-two seconds on August twenty-fourth.

In the upper right corner of the main screen, there was another timing board.

[Continuous absence of valid telemetry: 97 days and 18 hours]

Song Yao inserted Jiang Lin's temporary access card into the visitor console.

This card could read the original database, run task simulators, and generate instruction packages pending review, but could not access the uplink keys.

On the other side of the console sat a double-locked key box, with the two keys kept respectively by the mission chief designer and the measurement and control head.

Xu Kaiyang said, "There are still twenty-six people left in the team taking turns on duty."

"For the first month after losing contact, we were on duty all day, which later changed to window duty."

"Every capture record and failed attempt is in the database."

Jiang Lin sat down and first pulled up the failed attempts.

The work of ninety-seven days was not scattered across hundreds of logs.

The team organized them into twenty-seven fault trees, with each branch marked with supporting evidence, opposing evidence, sent instructions, and risk levels.

Common recovery methods had been almost exhausted.

They had also considered continuous blind transmission, but the possibility of qingqiong-1 being in a low-energy state was very high.

Erroneous continuous awakening would deplete the freshly accumulated power once again; if a forced computer switch occurred during memory writing, it might also destroy the last bootable image.

The team stopped not because they lacked courage.

They lacked a safe path that could simultaneously traverse multiple unknown states.

Jiang Lin spent a morning compressing the twenty-seven fault trees into four groups of state sets.

The first group: the main computer was still running, attitude control had failed, and the celestial body had entered passive slow roll.

The second group: the power controller periodically restarted, and only the transponder gained power briefly after the voltage crossed the threshold.

The third group: the safe mode was still executing, but the star sensor and sun sensor gave conflicting data, and the control law refused to take over.

The fourth group: the switching between machine A and machine B was interrupted, and the underlying remote terminal retained only a narrow-band receiving channel.

All four state groups could explain the existing carrier wave.

The ground still could not get enough evidence to delete any of the groups.

Song Yao stood behind him, watching the sets on the screen tighten layer by layer.

"If you have to bet on one group, which one do you choose?"

"I won't bet yet."

Jiang Lin pulled up the onboard instruction dictionary.

"The four states share a single underlying command entry."

"The first one only makes the remote terminal extend the carrier wave, without waking up the host, connecting attitude control, or rewriting the memory."

Xu Kaiyang found that command.

"A continuous transmission command used for factory testing."

"It has never been sent since entering orbit."

"What is its worst-case power consumption under the four states?"

The head of the power subsystem reported a number.

Jiang Lin asked again, "Based on the estimation of the last seven carrier wave leading edges, how much can be accumulated in each insolation segment?"

Another person projected the interval onto the main screen.

There was still a seventeen percent difference between the two sets of numbers.

Sending instructions directly might cause the low-power state to drop back to the power-off threshold just as execution began.

Jiang Lin split the instruction package into repetitive short pulses, each requiring the transponder to extend for zero point eight seconds, and then the ground would decide whether to send the next one based on the carrier phase.

"Turn the ground station into its temporary clock."

After reading the sequence, Song Yao raised a hand and called over two duty officers.

"Build a separate simulation branch and call the full power model."

The simulator ran the worst-case state first.

The battery voltage fluctuated close to the protection line, and each extended transmission of the transponder ended before power failure.

After one hundred and twenty rounds of Monte Carlo deviation injection, not a single round triggered an irreversible action.

Xu Kaiyang added the thermal control model, remote terminal clock drift, and antenna occlusion.

The results still fell within the safe zone.

The first command was only responsible for extending the reply.

The second command was to use the extended carrier to measure the roll phase.

The third command requested a frame of the lowest-speed telemetry within the eight-second window when the antenna was facing the ground.

As long as that frame was received, the four states would separate for the first time.

Jiang Lin did not draw a solitary best route on the whiteboard.

He connected a subsequent branch to every bit that could possibly return.

If the frame header was intact but verification failed, it would enter the low-speed repeat mode.

If only the power word was valid, it would first maintain solar incidence and not touch the attitude machine.

If the machine B boot flag was returned, it would freeze the machine B storage area and switch to machine B read-only diagnostics.

If the star sensor was abnormal while the sun sensor was valid, coarse orientation would be established along the sun vector.

Even if not even the lowest-speed telemetry could be received, the ground could still judge whether the command was executed based on the carrier extension amount, and then fall back to the first layer.

Lunch was brought back from the cafeteria by the duty officer.

The boxed lunch in front of Jiang Lin had been sitting there for twenty minutes, and the edges of the rice had already dried.

Shao Cen laid a pair of chopsticks across his keyboard.

"It's a tradition in the mission hall: whoever's chopsticks touch the keyboard first eats first."

"Is this procedure written in the manual?"

"Oral tradition, with an untraceable version."

Jiang Lin saved the instruction tree and picked up the boxed lunch.

"Then let's execute the current version first."

This meal split the people in front of the console into two groups.

One group continued to check the simulation, while the other sat in the back row to eat, swapping places ten minutes later.

No one gathered around Jiang Lin to ask how he walked through three months of fault trees in a single morning.

The twenty-seven trees had been here all along, and the parameters, logs, and engineering judgments had also been accumulated item by item by this team over ninety-seven days.

What Jiang Lin did was to rearrange the price of the problem.

He re-compressed all uplink records from the ninety-seven days onto a single timeline, and unfolded thirty-nine segments of carrier waves backward according to a new six-minute-thirteen-second cycle.

Several attempts from the past belonging to different ground stations and different dates fell into the same narrow window in terms of roll phase.

Among them, after twelve sets of low-power diagnostic commands were issued, phase tails of tens of milliseconds appeared at the ends of the carriers.

Viewed individually, the change was smaller than the receiver's judgment threshold at the time.

After twelve times of superposition, the direction of the phase tails was completely consistent.

Song Yao pulled up the duty log that first recorded this type of phenomenon.

The log was written by a measurement and control engineer who had just graduated two years ago.

On the nineteenth day of lost contact, he had marked a sentence: "Suspected onboard response, insufficient evidence."

The reviewer retained the original samples but did not write it into the mission conclusion.

Song Yao said, "If we had continued to transmit following this judgment at that time, the consequences would have been hard to control."

"So he was right to stop."

Jiang Lin connected the twelve sets of samples into the shadow star pending verification list.

"Now with cross-window coherent processing, they can be treated as clock measurements of the remote terminal."

"The original records and that engineer's annotations are all left in the verification report."

Those twelve attempts, once classified as non-responses, provided the upper limit of the real on-orbit response for the first-layer short pulses.

The clock drift interval in the instruction tree subsequently shrank by one-third.

When the duty engineer rushed to the hall, Jiang Lin had already written his name in the contribution records.

He stood by the console and finished reading the recalculated results, first confirming the original sample number before asking, "Ninety-seven days of guarding weren't in vain?"

"Every piece of raw data you guarded is working today."

For the first time, that entire wall of lost contact records in the back row of the hall turned from a failure list into an on-orbit calibration set.

In the past, every route required the ground to first believe in a single failure cause.

The current first-layer instructions did not care about the cause; they only bought the next piece of information, and the power and risks paid were locked within a range that the satellite could bear.

In the afternoon, an elderly engineer from the attitude subsystem came in with an independent model he had written himself.

He adjusted the three-axis residual magnetic moment to the upper limit of the design and simulated the incomplete deployment and locking of one side of the solar wings.

The satellite in the simulation rolled slower, and the six-minute-thirteen-second envelope was stretched to over nine minutes.

Jiang Lin connected the independent model into the instruction tree, and the state fell into the carrier phase trigger branch he had pre-written.

The fixed duration window was kept only as a control, and the formal sequence would automatically switch to this branch when the roll period exceeded the convergence interval.

The elderly engineer asked, "Could the conservative branch possibly wait one more circle even under normal conditions?"

"Waiting one more circle trades for the prior of the roll period."

"Accepted."

He signed his name in the independent review column.

This signature brought the official clearance from the attitude group.

Subsequently, each of the four subsystems sent one person to exchange models, specifically picking states different from their original judgments to conduct cross-tests.

Every branch given by Jiang Lin had withstood the most unfavorable parameter combinations; reviewers could change the boundaries, but could not alter the already locked Physics constraints.

After two rounds of exchanges, only verification numbers were added to the whiteboard, and no remedial clauses were added.

The mission secretary bound all the review records into a volume, and for the first time, Jiang Lin's title appeared on the cover: qingqiong-1 Recovery Architecture Lead.

In the evening, the instruction tree had passed the five groups of reviews for power, attitude, thermal control, software, and measurement and control.

Song Yao submitted it for official flight program review, but the system reported a yellow prompt at the third layer.

[Missing engineering satellite equivalent verification records]

The prototype electrical satellite of qingqiong-1 had been disassembled a year after launch, and the remaining spare parts were scattered across three units.

The existing mission simulator could cover software and dynamics, but could not reproduce the real timing of the remote terminal repeatedly powering on under low voltage.

This was also one of the reasons why the team had previously hesitated to combine blind transmission instructions.

Xu Kaiyang pulled up an inventory table.

"There is a backup for the main control board, the power controller is in Xi'an, and the transponder engineering unit is in Nanjing."

"For the battery, we can only find a substitute of the same model."

"It will take at least three weeks after gathering them all."

There were only twenty-eight days left until Jiang Lin's next transmission.

qingqiong-1 could wait three weeks, but the battery on the satellite might not be willing to follow the ground schedule.

Jiang Lin took the inventory table and wrote down the interface numbers next to the three addresses respectively.

"There's no need to move the entire engineering satellite back."

"What about the missing structures, wire harnesses, and payloads?"

"The ground only needs to create the same fault."

He opened the standard mission module blueprints of the Low Entropy Workshop and dragged four hexapod platforms that had already withdrawn from commercial delivery to the center of the page.

"The boards will be shipped tonight."

"Seventy-two hours later, we'll let the shadow star fall sick once first."

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