"The coordinate system is complete."

"The attitude-orbit coupling model has been established."

"The origin O is the center of mass of the target, the X-axis coincides with the central axis of the core module, the Y-axis is perpendicular to the longitudinal symmetry of the core module, the Z-axis is perpendicular to the Y-axis, and the three axes are orthogonal to the right-handed axis...... The inclination of the central axis of the space station is 14 degrees, 25 minutes and 37 seconds. ”

"Attitude control model complete!"

"The obstacle avoidance model is complete."

Lao Mao and Tang Yue are very cautious, it is not easy to use the SPT276 ion rocket to stabilize the attitude of the space station, this engine has been installed on the Falcon III. asteroid probe, used for long-distance orbit change work, it is not the original attitude control system on the space station, even the control data link is added later, and the three-axis stability of the joint space station itself has been scrapped in the impact.

"The angular velocity of the joint space station exists in both the X and Z axes." Tang Yue said that according to the data transmitted by the computer of the space station system, the space station is not simply spinning, it is rolling and turning while rotating.

"I've seen it." The old cat stared at the slowly rotating space station model on the monitor, "The degree of freedom of the SPT276 engine is very limited, and the velocity vector on the X-axis plane can be solved, but the Z-axis plane is more troublesome...... Miss Mai Dong, can you hear me? Miss Mai Dong? ”

"Mr. Cat, I can hear you."

"Listen to me, can you see the sun now?" The old cat asked.

"Yes."

"Okay." The old cat's face sank like water, "The sensors on the space station are basically scrapped, we have to find a reliable reference, the best reference is the sun, we have to orient the sun." ”

"Mai Dong, keep an eye on the sun." Tang Yue continued, "The sun, the porthole, and your eyes are three points and a line, and this line is the baseline...... Got it? Mai Dong, be sure to keep an eye on the sun. ”

Mai Dong raised her head, and the bright sunlight fell into her eyes through the glass porthole, and soon passed through the window again, the star was more than 220 million kilometers away, and it took the photons thirteen minutes to cross this long distance, and they drew the straightest line in the universe in the void - without taking into account the influence of gravity, the light travels in a strict straight line, and no amount of precision can draw such a line.

Photons drew a baseline for them.

As long as you keep your eyes on the sun.

"The next step is to turn off most of the functions of the space station system computer and allocate power to the SPT276 ion engine." The old cat sat on the side and began to adjust the power distribution of the space station.

The SPT276 ion thruster is the most powerful electric rocket, but it is also the first electric tiger, the power consumption after booting is amazing, its performance on the Falcon III really interprets what is called "five hours of charging, two minutes of power-on", due to the short duration of work, the advantages of Hall thrusters are actually not shown - but after all, this is produced by JAXA, and the Japanese are always strange in their aerospace ideas.

The battery capacity of the Joint Space Station is far greater than that of the Hayabusa III asteroid probe, but it can't withstand the craze.

As soon as the old cat's voice fell, all the LED lights above Mai Dong's head went out, and the old cat remotely turned off the computer in the space station, and transferred all the power to the engine, leaving only the communication system still working.

"Miss Mai Dong, test the communication system."

"Communication is normal."

"It has a thrust of only seven kilograms." Tang Yue leaned down, "How long will it take us to control the space station?" ”

"Although the thrust is only seven kilograms, the good thing is that our force arm is long enough, because the SPT276 is mounted on the truss, although the thrust is a little smaller, but as long as the force arm is long enough, there is no need to worry about the torque, and ...... I estimate that the total mass of the Joint Space Station today is less than 100 tons. ”

The old cat is connecting the battery to the supercapacitor, and the SPT276 is a 600 kilowatt giant ion thruster, and its instantaneous energy release density is much higher than that of the space station's battery pack, so the SPT276 must go through energy storage between starts.

The capacitors responsible for energy storage are a group of capacitors, known as supercapacitors, which are actually the bulk of the SPT276's fat volume, which is very sensitive and can maneuver the engine with millisecond precision.

"After the supercapacitor is charged, the remaining power of the main battery pack is 2 percent, and the remaining power of the secondary battery pack is 33 percent."

The two battery packs in the core module of the Joint Space Station are all-solid-state lithium-polymer batteries with an energy density of more than 400 watt-hours per kilogram.

"How long does a discharge work?"

"The total working time of the engine is five minutes, and the actual deceleration time is forty minutes under the pulse working state." The old cat replied, "We should be able to reduce the angular velocity of the station's spin to seven degrees per second." ”

"And then?"

"Then wait for the next charge." The old cat glanced at the time, "The next charge should be six hours before the second adjustment can begin." ”

"Six more hours to wait?"

At this critical juncture when the fate can be decided in one second, Mai Dong's life and death are hanging by a thread on the track, but the rescue on the ground is as slow as a turtle crawling.

"Because the solar panels are gone." "After all, we only have four windsurfing boards left – all mindful!" SPT276 is ready to start! ”

The old cat turned on the Hall thruster on the truss, the xenon ions accelerated in the electric field, and the high-speed plasma jet began to do work for the space station, but Mai Dong didn't feel anything, the core module was still rotating, and occasionally there was a dull clanging sound, which was the debris of the space station hitting the crystal module, the thrust of the electric rocket was really weak, coupled with the precise manipulation of the old cat, the whole deceleration process lasted for more than forty minutes.

After the power was cut off, the crystal cabin was just an empty shell, Mai Dong looked out the window, and the closest piece of shard to her was suspended a few meters away, it could be the shell of a certain module, about the size of a thermos cup cap, slightly curved, with white skin on one side and silver metal on the other, it was slowly flipping, reflecting the sunlight one by one.

Mai Dong was very thirsty, but she did not dare to drink water.

There are now only three liters of fresh water left in the core module, all of which are kept in the water bags of the spacesuit, and the girl does not know how long she will have to rely on this little water, she has lost the OGS cabinet, and oxygen and fresh water cannot be circulated.

From now on, water and oxygen are non-renewable resources.

There was another slight muffled sound, a "bang".

Apparently something else had shards crashed into the core module, but fortunately the relative speed between them was not fast.

"Is there anything I can do?" Mai Dong asked, "Except for staring at the sun." ”

"Girl, just protect yourself, and we'll solve the other problems......"

The old cat suddenly interrupted Tang Yue, "Miss Mai Dong, if you want, sing a song." ”

Sing?

Tang Yue and Mai Dong were both stunned, the latter was stunned for a few seconds, and then smiled.

"Okay, what are you singing?"

"Just sing...... "God Is a Cat" the old cat stared at the space station on the monitor. ”