Once We Lived in Nanjing

Ban Xia sat on the steps at the entrance of the apartment building, holding a slender, withered bamboo pole, one end in her hand and the other resting beside her foot, humming a song leisurely and squinting one eye, checking whether the bamboo pole was straight enough.

Next, she tied a one-meter-long white plastic strip to the end of the bamboo pole, and while busy with her task, she occasionally looked at the thin bamboo poles stuck in the lawn across from her. The breeze fluttered the ribbons tied to the poles, and she watched them for a while before burying her head back down and resuming her work.

After tying the strip securely, she carried the bamboo pole upstairs and erected it in the attic.

She had already set up five or six such poles. Holding a small notebook and a pencil in her hands, she checked four times a day, and then noted in the notebook:

"December 10.

8:32 AM, southeast wind, level two.

12:02 PM, northeast wind, level three.

4:33 PM, north-northeast wind, level three.

10:01 PM, west-northwest wind, level three."

She checked once in the morning, noon, afternoon, and evening - four times a day. This was Ban Xia's new job; during the breaks in debugging PSK data transmission links, she would do this, like a meteorological investigator.

Wind measurement is not easy, it can only be estimated. BG4MXH said there was a mnemonic for estimating wind force, like a chant, "zero level, the smoke shoots straight into the sky; first level, the smoke drifts with the wind; second level, a gentle breeze on the face; third level, leaves rustle and flags flutter; fourth level, branches cause flying paper pieces — just like Oppenheimer, grab a handful of paper, throw it into the sky, and if they are blown away by the wind, then it's fifty thousand tons... ah spit, definitely a fourth level wind!"

"BG, how is analyzing this useful?"

"I'm not sure, it's just their request," Bai Yang responded. "Uncle Zhao and the others have been quite secretive these past few days, maybe they have some big plans. Miss, is the camera on your side working normally now? OVER."

"I replaced it because the new one couldn't focus correctly, then I replaced it again."

Yesterday, Ban Xia accidentally broke the camera while fiddling with it and had no choice but to replace it with a new one.

"Any problems running the program? OVER."

"There are still bugs, but at least it's all installed now." The girl sighed deeply. "It's so difficult, why is it so hard just to meet you guys."

She had experienced the difficulty of debugging PSK; it was much harder than AFSK. At her most difficult times, Ban Xia felt lost in an endless mountain of code, not knowing who she was, where she was, or what she was supposed to do. At those moments, she just wanted to violently smash the motherboard and monitor, and then burn everything to ashes.

But once she calmed down, she had no choice but to face these perplexing codes, and with assistance from the experts across from her, she would painstakingly troubleshoot bugs from scratch, each time a draining marathon.

As one of the world's most astute programmers, ninety-nine percent of her time was spent troubleshooting bugs.

"Technical problems are the most difficult to solve, they're like math tests; if you don't know how, you just don't know how. No matter how hard you wrack your brain or push yourself to your limit, it won't help. If someone gave me a math test for college entrance exams now and told me scoring full marks would save the world, I could only stare blankly." Bai Yang also sighed, "Things that a bit of effort can fix aren't truly difficult. Real difficulties are impossible even to begin, OVER."

"BG, when is the rocket going to launch?"

"It's scheduled for the 18th of this month, at the French Guiana Space Center, OVER."

"Where is that?"

"In South America, Miss, do you know where South America is?" Bai Yang said, "On the other side of the Earth, the satellite is being installed at the moment and will be air transported to the Guyana Space Center for final assembly, OVER."

The girl was silent in the dark for a while, likely trying to grasp how far away the other side of the Earth is.

She shook her head, unable to figure it out. She could only imagine a world as big as Nanjing City, anything beyond that was beyond her comprehension.

"What kind of satellite is it?"

"It's a super camera. It will fly above your head to take photos, locate the position of the big eyes, and then transmit it to us so we can create a counterstrategy," Bai Yang responded, "It's a reconnaissance soldier. All military operations require sending out reconnaissance soldiers to scout the enemy conditions before deployment, OVER."

"Really?" The girl was surprised, followed by a hint of excitement, "Can it take a photo of me?"

Bai Yang hesitated.

"That... probably not, because you are too small, and it can't see you, OVER."

Even though the satellite carries a synthetic aperture radar imaging system capable of resolutions under one meter, capturing a human girl from a vertical angle is challenging, and its mission is not to take photos of Ban Xia. The big eyes coupled with long legs span seven to eight meters, easily spotted under the radar's vision.

"Oh," Ban Xia was a bit disappointed.

"The imaging quality of that thing isn't good, and it only produces black and white images," Bai Yang comforted her, "You wouldn't want it to take your pictures, Miss. It doesn't compare to the camera you have in your hand, OVER."

"So when will it be coming?"

"In my time coordinate system, it will return to Earth's orbit in twenty years; in your time coordinate system, it will return to Earth's orbit in eight days," Bai Yang answered, "Assuming it doesn't encounter any issues halfway, OVER."

Nowadays, the headquarters has almost formed a path dependence. Everything is sent to space, which, in Zhao Bowen and others' view, is the best way to transport the Time Slow Delivery. Far from Earth, in the vastness of space, no interference, just a few minor drawbacks—like preparation taking too long, high transportation costs, possible failures during launch or recuperation, or it might get damaged during the twenty years in space—well... this makes sending things to space not such a great idea after all.

But it's cool!

Is there a more important reason than being cool?

"So in my time coordinate system, it's already in space, right?" Ban Xia lifted her head and looked at the dark ceiling.

It's really fascinating to think about, time is such a miraculous thing, the yet-to-be-launched satellite seems to have already been traveling in space for twenty years from her perspective.

"Not necessarily, Miss," Bai Yang said, "Perhaps in eight days, if the launch fails, then there won't be anything arriving on your end. Do you recall the first law of Time Slow Delivery? You can only receive what has already been confirmed on our side. If it hasn't become reality here, it won't be reality there either, OVER."

"What if we want to make it a reality?" Ban Xia asked, "Like if you set the satellite's return time to tomorrow and I receive a signal from the satellite tomorrow and transmit it to you, but you haven't launched the satellite yet..."

"From my personal experience with time capsules, the outcome would be failure. Such a fact cannot be established, the universe won't allow it, and you simply would not receive any signals from the satellite," Bai Yang pondered for a moment, "Then we would learn about the satellite's failure to return, cancel the launch temporarily, choose another time for relaunch, and cause you not to receive any signal from that satellite tomorrow, OVER."

"Then is there something I need to do?" Ban Xia asked.

"Yes," said Bai Yang, "The satellite can't directly communicate with the radio station; you need to assist in receiving the satellite signals, OVER."

"How can I assist?"

"Beat it!" Bai Yang said, "Beat the satellite!"