Video production: Ge Taiyi

"As soon as the People's Daily went out, the streets were filled with gongs and drums to celebrate... The satellite passed Beijing and flew from the west on time... This is a deep impression!"

In an exclusive interview with the People's Daily Power Forum, Hu Qizheng, a member of the overall team of the "Dongfanghong-1" satellite, sighed about the scene after the successful launch of China's first man-made earth satellite.

At 21:35 on April 24, 1970, the successful launch of the "Dongfanghong-1" satellite made China the fifth country to launch a domestic satellite with a homemade rocket. Hu Qizheng said that at that time, the positioning of the satellite was a scientific test satellite, which was mainly used to detect the space environment and satellite technology experiments. Its mission objectives can be summed up in 12 words that are well known to everyone: can go up, can grasp, can see, and can hear.

As China's first man-made earth satellite, the "Dongfanghong-1" satellite is a monument in the history of China's aerospace. From the perspective of composition, the "Dongfanghong-1" satellite has seven major systems - structural system, thermal control system, energy system, tracking system, music and telemetry system, antenna system, attitude measurement system; From the structural point of view, the "Dongfanghong I" satellite can be divided into three parts: the shell, the instrument cabin and the bearing cylinder. The shell is a 72 faceted body. A 40cm long ultrashort wave antenna is installed at the top of the upper hemisphere. Four 3m long short wave rod antennas and two groups of microwave antennas are installed on the belt. The instrument cabin is equipped with many equipment, including the "Dongfanghong" music generator Short wave transmitter, microwave transponder, ultrashort wave beacon, silver zinc battery, etc.

"All the components, equipment and materials on the 'Dongfanghong-1' satellite, as well as the overcoming of many theoretical and technical difficulties, are our own products and achievements." Hu Qizheng cited the thermal control system of the satellite as an example. In the space environment, whether there is solar radiation will form a huge temperature difference, In order to make the satellite work normally, the temperature must be controlled within the normal working range of the instrument. Some countries' first satellites have lost their working ability quickly due to thermal control problems.

"At that time, the thermal control equations, calculations, materials, tests, and components all needed the Chinese to study themselves, and everything started from scratch." Hu Qizheng recalled that at that time, there was almost no condition in China to support the realization of this technology. There were no ready reference materials, nor computers and high-end manufacturing equipment.

There is no way, the older generation of spacemen will create ways. Hou Zengqi, a thermal control expert of the "Dongfanghong-1" satellite, recalled in an interview with the media that at that time, all the staff relied on some basic knowledge and combined with the actual situation of the satellite to derive their own formulas, establish equations and calculate equations. Since there is no computer, use an abacus to calculate these "astronomical figures" manually.

Even under such harsh conditions, the "Dongfanghong-1" satellite still took the first step on the path of Chinese spaceflight. The older generation of spacemen calculated the thermal control system of the "Dongfanghong-1" satellite by hand.

Hu Qizheng introduced that the "Dongfanghong-1" satellite's shiny surface is not only for "seeing", but also to ensure its thermal control performance: the aluminum alloy on the surface of the satellite is bright anodized to obtain an optimal state of solar absorption and satellite radiation heat dissipation ratio. It does not need to consume energy, and only depends on the physical characteristics of the satellite surface to adjust the heat exchange with the outside space to reach the required temperature.

Hu Qizheng proudly said that the thermal control of the "Dongfanghong-1" satellite was very ideal. The temperature parameters of the last day fully met the expected requirements, and the 28 days of operation were normal. The data achieved by its thermal control system, even today, can still meet the requirements of most satellites.

"There is a small regret. We originally designed a set of solar cell power supply system for Dongfanghong No.1, but because of the insufficient production at that time, we had to simplify it." Hu Qizheng said that Dongfanghong No.1 finally used silver zinc batteries.

On March 3, 1971, the second satellite, "Shijian No.1", was successfully launched with the "Dongfanghong No.1" backup satellite loaded with the solar cell power supply system designed that year. "This satellite has been in orbit for eight years, and it didn't stop working until the end of its orbital life when it fell."

The "Dongfanghong I" launched before the "Shijian I" is still flying. Over the past 52 years, it has witnessed the development and progress of China's space industry again and again.

Each generation has its own mission. At this moment, three astronauts, Chen Dong, Liu Yang and Cai Xuzhe, are taking the Shenzhou XIV manned spacecraft to carry out the mission of the comprehensive construction phase of the Chinese space station in space, making efforts to explore the more distant stars and sea.

Share to let more people see