Chang'e 4 has landed on the moon, and from now on Guanghan will no longer be cold.

The backside of the moon, which has been silent for billions of years, has finally welcomed its first visitor from Earth - Chang'e-4. On January 3, Chang'e-4 successfully set foot on the backside of the moon after flying over 380,000 kilometers and trekking for nearly a month.

Behind the scenes of this landmark drama in the history of mankind, countless Chinese aerospace and science and technology workers have devoted their life's efforts and blood, among which there is an indispensable Ningbo force.

fly to the moon

For more than 50 years, he has only done this one thing

At 2:00 a.m. on December 8, 2018, Xichang, Sichuan Province, the "Moon City". The Long March 3B remote rocket carrying the Chang'e-4 detector ignited and lifted off, opening the first soft-landing exploration trip on the back of the moon for mankind.

Nineteen minutes after liftoff, the vehicle and arrow were successfully separated, and Chang'e-4 successfully entered the Earth-Moon transfer orbit with a perigee of about 200 kilometers and an apogee of about 420,000 kilometers. Compared with the launch of Chang'e-3, the rocket's designed orbiting accuracy has been improved by more than 30 percent.

More than 2,000 kilometers away from Beijing, academician Yu Menglun received the news at the first time and finally put down his heart.

It is understood that escort Chang'e 4 to the moon rocket - Long March 3B remote thirty, is by the China Academy of Launch Vehicle Technology total development. And bear the launch vehicle ballistic design of the class is by the Ningbo Chinese Academy of Sciences academician, one of the founders of China's aerospace industry Yu Menglun led the "Yu Menglun class group".

"Rocket launches can not guarantee 100 percent success, rocket launches are faced with intense vibration mechanics of the environment, although the last decade, the rocket launch success rate increased rapidly, but the risk is still there." Yu academician said.

Launch vehicle ballistic design is the core parameters of the rocket gene and soul, due to the high precision requirements and large amount of calculations, ballistic design is called the rocket launch design "overall in the overall". Yu Menglun was the fifth team leader of this team, and has since been awarded "Honorary Lifetime Team Leader".

In 1960, Yu Menglun, who graduated from the Department of Mathematics of Peking University, joined the Fifth Research Institute of the Ministry of National Defense, which had just been established, and joined the ballistic team at the lowest level, participating in the ballistic design of ************ rockets. Since then, he has been doing one thing for more than 50 years - designing "****** flight paths" for missiles and rockets.

From the Dongfeng I, Dongfeng II, to the Long March I, Long March II, to the Shenzhou I, Shenzhou II, and then later on "Chang'e" to the moon, "Shenjiu", "Tiangong" space hand in hand! ...... Yu Menglun and his team designed the most beautiful flight trajectory for every step of China's entry into space.

Exploring the Moon

Shining eyes for Chang'e

"The "eyes" used by the Chang'e-4 landing camera are developed by Zhejiang University and produced by Ningbo-listed Yongxin Optics.

According to Yongxin Optics, due to the special space environment, full of radiation, "Chang'e 4" landing camera lens material is extremely special, is radiation-proof glass. Its lens barrel is made of titanium alloy. This ensures that in the extreme environment of space, the "eyes" of the high-definition imaging quality!

In addition, because the lens assembled on the ground will have air inside, into the vacuum environment of space, the air inside the lens and the external environment will form a pressure difference caused by deformation, resulting in image quality degradation, or even destruction. For this reason, the lens is specially designed with ventilation holes to balance the internal and external environment of the lens.

In order to ensure high-quality imaging, the manufacturing team at Yongxin Optics has gone through countless tests for each process.

"It has to be done to the extreme. If there is a problem in one of the processes, it will lead to a 'strike' of the whole lens. In order to make sure that it is foolproof, advanced technology is applied to make the satellite optical lens integrate radiation protection, shock resistance, resistance to drastic changes in temperature, and dust protection." Yongxin Optical General Manager Mao Lei said that for this "eye", they had spent 5 years, made more than 100 lenses, recorded each part, each process of detailed data, and finally accumulated tens of thousands of sets of information and data.

In fact, this is not the first time that Yongxin Optical made the "eyes" of the moon exploration.

As early as 2010, when Chang'e-2 was launched, the lenses of three surveillance cameras and one landing camera developed by Yongxin Optics together with Zhejiang University were mounted on it. The "eye" of Chang'e-4 was also used on Chang'e-3, recording the landing of Chang'e-3 on the lunar surface. "The eye was also used on Chang'e-3, recording the thrilling six minutes when Chang'e-3 landed on the lunar surface.

YSP also participated in the manufacturing of the optical camera lens for the "Magpie Bridge" relay star. This camera system is also the only camera system on the Magpie Bridge relay star. "The Magpie Bridge Relay Star provides Earth-Moon relay communication support for the lander and rover of Chang'e-4.

In addition, Wang Jianyu's team also installed the infrared imaging spectrometer (IRIS), an infrared eye, for the lunar rover, which reached the back of the moon for the first time. Wherever the rover goes, this pair of "eyes" will look at which piece of the lunar surface. By acquiring fine spectral information, the instrument can help scientists identify the composition of moon soil and moon rocks. Wang Jianyu introduced that Chang'e-4 infrared imaging spectrometer not only integrates the latest remote sensing technology, but also successfully realizes lightweight and miniaturization, weighing less than 6 kilograms, and its comprehensive performance is better than that of similar products in Europe and the United States.

Moon landing.

"We went down with our eyes open."

On January 3, 2019, the Chang'e-4 probe arrived over the Von Karmen impact crater in the South Pole-Aitken Basin on the back of the Moon, preparing for mankind's first soft landing on the back of the Moon.

To accomplish this feat and find a suitable location and a flat surface for the Chang'e-4 probe to land on, the laser range finder and laser three-dimensional imaging sensor equipped on the Chang'e-4 probe are indispensable.

In charge of developing these two devices is the team of academician Wang Jianyu of the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences. Wang Jianyu, a native of Ningbo, Zhejiang Province, graduated from the physics department of the former Hangzhou University.

According to Wang Jianyu, the laser range sensor is like a high-performance "reverse radar". When the Chang'e-4 lander is 15 kilometers above the moon's surface, the laser distance sensor starts working, transmitting laser pulses to the moon's surface twice a second. The precise distance of the Chang'e-4 lander relative to the moon's surface is obtained by measuring the time interval between the return pulse signal from the moon's surface and the pulse signal emitted by the laser, with a measurement accuracy of within 0.2 meters.

"When the lander descends to about 8 kilometers from the lunar surface, the attitude is adjusted, and the laser ranging sensitizer will switch the direction of ranging along with it until a smooth moon landing is completed." Wang said the core components of Chang'e-4's laser range sensor, such as the laser light source, detector and high-voltage power supply, are all domestically developed and have further improved the system's degree of integration and lightweighting.

The laser three-dimensional imaging sensitizer will help Chang'e-4 solve the problem of "where to land". "Although the intended landing area of the Aitken region is relatively flat, but the surface still exists high slopes, craters, boulders and many other uncertainties, so accurate obstacle avoidance is extremely important." Wang Jianyu said.

When Chang'e-4 reaches the hovering position 100 meters from the lunar surface, the laser 3D imaging sensitizer starts to work: it collects 3D images of the lunar surface, identifies stones higher than 15 centimeters or craters lower than 15 centimeters, and ensures that the detector lands in a safe area. The work of scanning and imaging so finely is done in just a few seconds.

It is worth mentioning that China has applied the laser 3D imaging technology to lunar landing earlier among several spaceflight powers, and the application is now very mature. Academician Wu Weiren, chief designer of the Moon Exploration Project, once said figuratively: the Americans landed on the Moon with their eyes closed, but we went down with our eyes open.

Chang'e-4's "joints" are also tested in Ningbo. According to the Ningbo Branch of the Academy of Military Science, the key valves on the detector were tested by the academy, providing a guarantee for Chang'e's smooth exploration of the moon.

The key valves are equivalent to the detector's "joints", and the whole process of orbit change, spacecraft attitude control, obstacle avoidance, hovering and slow landing is accomplished by various key valves working together.

There are nearly 100 valve bodies on Chang'e-4, welded by electron beam welds, most of which are directly exposed to the complex environment of the universe, leaving no room for the slightest imperfection. This puts higher demands on the precision of inspection instruments and the skills of personnel. Through more than 20 years of experience and independent innovation, the Ningbo Branch of the Institute of Science and Technology, Ningbo Branch of the physical and chemical testing center developed a high-precision industrial CT inspection technology to ensure the quality and reliability of these key components.

Not only that, previously, the team has also tested for Shenzhou series, Tiangong 1, Tiangong 2, Chang'e series and other national aerospace products. In addition, the team is also responsible for the quality control of the key components on the first domestic magnetic levitation train with independent intellectual property rights and the Hangzhou Bay Cross-Sea Bridge.

As the earliest unit to carry out industrial CT inspection applications in China, the institute also took the lead in formulating national standards and national military standards in this technical field, filling the gaps in this technical field in China.

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Ningbo's Aerospace Power

In the whole process of China's aerospace development, Ningbo academicians and scientists and Ningbo "civil military" enterprises have been quietly dedicated.

This time to undertake the laser range sensor and laser three-dimensional imaging sensitizer research responsible for academician Wang Jianyu, in 2016, assumed the world's first quantum science experiment satellite "Mozi" launch commander-in-chief.

Academician Le Jialing, born in Zhenhai, is an aerodynamics expert in China's space industry. He has long been engaged in the development of supersonic aerodynamic ground test equipment and aerodynamic theory and experimental research on strategic weapons and launch vehicles, and has achieved a series of significant research results.

And Yu Mengsun, a native of Yuyao and an academician of the Chinese Academy of Engineering, is the founder of China's aerospace biomedical engineering and an expert in aeromedical and biomedical engineering.In 1958, he took part in the successful development of China's first aeromedical telemetry device, which for the first time carried out telemetry on pilots flying at a height of 3,500 meters, and started China's aerospace biomedical engineering research career.

The city's enterprises were also behind the successful launch of Tiangong II on the night of the Mid-Autumn Festival in 2016. Providing high-purity oxygen-nitrogen gas mixture for the Tiangong-2 astronaut system before the launch was a pressurized gas mixing gas source vehicle. The development task of this vehicle is completed by Ningbo XINGJIAN Aerospace Machinery Co.

In addition, the magnets used in the core components of the servo motors in the Tiangong-2 Space Laboratory are produced by Ningbo Xingxing Materials Technology Co. After Tiangong-2 reaches the scheduled orbit, the solar cell sail panels that provide electricity will be opened, and this action is controlled by the motor.

Reporter Le Snapdragon Wang Jing