What did they do on the "Tianwen No. 1" flight distance of 160 million kilometers "toward the fire"?

　　At about 23:00 on September 20, 2020, at the Beijing Aerospace Flight Control Center, the flight control team of my country's first Mars exploration mission successfully completed the second midway correction of the Tianwen-1 orbit.

　　Since its launch on July 23, Tianwen-1 has been in orbit for 60 days, about 19 million kilometers away from the earth, and the flight distance is about 160 million kilometers. During this period, the Tianwen-1 and its flight control team have been in orbit. What story happened?

Set a small goal, first fly it 100 million!

　　The flight of Tianwen-1 to Mars was long and far away. The flight controller who took care of it on the ground divided the flight controller of Tianwen-1 into goals and realized it gradually.

In addition to time as a unit, flight mileage is of course also an important measurement method. The first small goal in units of "100 million" was achieved at 10:08 on August 28.

　　August 28 is the 36th day of the Tianwen-1 probe flying in orbit. It is 10.75 million kilometers away from the earth. Careful readers can't help but ask why the flight mileage exceeds 100 million, but the distance from the earth is only more than 10 million. ?

　　This is because when Tianwen-1 is flying to Mars, it flies in an arc along a maneuvering orbit, and will keep moving away from the earth.

But at the same time, both the earth and Mars are revolving around the sun in their respective orbits, showing a state of "you go and I go".

Therefore, relative to the location at the moment of launch, the mileage of Tianwen-1 is accumulating at a high speed, while the distance from the earth does not move away so quickly, and finally shows two different distances.

What is the purpose of the second midway correction?

　　During the flight of Tianwen-1 to Mars, due to the long-term unpowered flight of the probe, the tiny position and speed errors will gradually accumulate and amplify. Therefore, the ground measurement and control system needs to correct the probe's flight trajectory during the flight to ensure that the probe Always fly on a predetermined orbit.

　　For the second midway orbit correction, the staff of the Beijing Aerospace Flight Control Center performed the start-up and ignition operation on the four 120N engines of Tianwen-1, which not only corrected the orbit, but also tested the state of the engine.

　　At 23:00 on September 20, 2020, at a distance of about 19 million kilometers from the ground to the ground, the Tianwen-1 Mars Rover implemented the second midway correction control of the ground-fire transfer orbit as planned. The fixed start-up time is about 20 seconds. After the test spray Confirm that the engine is currently in good condition.

do you know?

As the earth’s weather turns cooler, Tianwen No.1 needs heating?

　　From July to September now, if you are in the north, you can clearly feel the temperature change. In the northeast of our country, heating will be even in one month. Similarly, Tianwen-1 is flying. "Heating" is also needed in the process.

　　As the distance from the sun gets farther and farther, Tianwen-1’s demand for solar energy will gradually change, so the probe will make certain adjustments to the solar panels to meet the power supply. This change will be implemented after the second halfway correction. .

　　While adjusting the angle of the solar panels, it is also necessary to adjust and control the attitude of the probe itself, so that the communication between Tianwen-1 and the earth is smooth.

It is necessary to precisely control the solar windsurfing board and adjust the attitude of the probe, which places high demands on the attitude control of the Beijing Aerospace Flight Control Center.

　　As time goes by, it will experience insufficient heat energy directly irradiated by the sun. That is to say, Tianwen No.1 can only receive light energy through solar panels, but does not have enough heat energy to maintain body temperature.

As the body temperature of the detector drops, you need to power on yourself to heat up on Tianwen No. 1 to keep the equipment on the detector running normally.

Just like our winter heating, the difference is that the heating of Tianwen No.1 is more accurate. It can identify which part of the body is too cold, and it will accurately "heat" according to the area, saving energy while ensuring equipment safety.

　　At present, Tianwen-1 is still flying steadily under the strict monitoring and control of the Beijing Aerospace Flight Control Center. It will soon exceed its own mileage of 200 million kilometers. The flight controller on the ground will also be consistent to ensure the stability and health of Tianwen-1. .

This process is long and not easy. They put their heartfelt voices in their singing, deducting the unique style of astronauts.

　　(CCTV reporter Cui Xia Tao Jiashu, Beijing Aerospace Flight Control Center Song Xingguang)