China's space industry is 67 years old today! Today, we will show you how to look at space industry from a different perspective

On October 8, 1956, the Fifth Academy of the Ministry of National Defense was formally established. This is my country's first rocket and missile research institute. This became the starting point of my country's aerospace industry! Two bombs and one satellite, manned space flight, lunar exploration, new era Beidou... Over the past 67 years, generations of Chinese aerospace workers have worked hard and created miracles in the aerospace industry! Happy birthday to China's aerospace industry! Today, let's talk about some little-known facts about China's aerospace industry.

China Aerospace: Two Bombs and One Satellite

How is the Dongfanghong-1 satellite doing now? Let's talk about the star of "two bombs and one satellite"

The “two bombs” actually originally referred to the atomic bomb and the missile. On October 16, 1964, my country’s first atomic bomb was successfully detonated; on October 27, 1966, my country’s first ground-to-ground missile equipped with a nuclear warhead was successfully detonated; on June 17, 1967, the first hydrogen bomb was also tested. So later, the two bombs were understood to mean “nuclear bomb” and “missile”.

What is "one star"? It is an artificial satellite. On April 24, 1970, my country's first artificial satellite, Dongfanghong-1, was successfully launched, which meant that the two bombs and one satellite project was successfully completed.

The design life of Dongfanghong-1 was only 20 days, but it actually worked for 28 days. During these 28 days, it not only played the song "Dongfanghong", but also returned some telemetry data and space exploration information to the ground. After that, it lost contact with the ground, but it is still in orbit until now.

Then we have to talk about the life of the satellite. For a satellite, it has two lifespans, one is the working life and the other is the orbital life. The working life refers to the time that the satellite actually works effectively, which corresponds to a design life in the early stage. The orbital life refers to the time that the satellite flies in orbit, during which the satellite may no longer work. Since there is no return mechanism, Dongfanghong-1 is currently in this state of in-orbit operation.

Will Dongfanghong-1 continue to operate like this?

Not really. Dongfanghong-1 is a near-Earth satellite. Generally, orbits within 2,000 kilometers are considered near-Earth orbits. Although the air in near-Earth orbits is thin, it is not absent. Therefore, air resistance will cause the satellite orbit to become lower and lower, gradually losing kinetic energy, and the orbit will change from an ellipse to a nearly circular shape, and eventually enter the atmosphere and crash. Of course, it is not ruled out that it will encounter meteors, space debris, etc. during this period. The initial orbit of Dongfanghong-1 was 439 kilometers at perigee, 2,384 kilometers at apogee, and an oblateness of 0.125. As of 2017, the data observed by people showed that the perigee became 429 kilometers and the apogee became 2,036 kilometers, which shows that this orbit is shrinking. Moreover, the density of the earth's atmosphere basically increases exponentially with the decrease in altitude, that is, the lower the orbit is, the greater the resistance will be. According to theoretical data, it is very likely that Dongfanghong-1 will operate in orbit for 70 or 80 years.

Dongfanghong-1 is just the first shot in the space industry. On January 5, 2020, the Dongfanghong-5 satellite common platform had its first successful flight, and its performance has undergone earth-shaking changes. The orbital altitude has increased from hundreds of kilometers to tens of thousands of kilometers, the weight has increased from hundreds of kilograms to several tons, and the life span has increased from dozens of days to more than ten years. Now we can not only launch satellites, but also the Chang'e lunar exploration, manned flights, etc. The starting point of all these feats is inseparable from the hard work of the older generation of scientists, the hard work of the new generation of scientists, and of course the seeds of hope planted for us by Dongfanghong-1.

China Aerospace·Manned Spaceflight

Why is my country’s manned space landing site chosen on land?

There are two ways to recover manned spaceflight: one is recovery at sea and the other is recovery on land. The United States uses recovery at sea, while the Soviet Union/Russia uses recovery on land. Why does my country also use recovery on land?

The choice of land as the landing site for my country's manned space flight is a scientific choice made after comprehensive consideration of multiple factors, and it has distinct Chinese characteristics.

First of all, the landing of a spacecraft on land requires relatively simple structural design of the spacecraft, and has low requirements in terms of water tightness, power supply, etc.

Secondly, the comfort and safety of astronauts waiting for rescue on land are much higher than at sea, and the investment in land rescue is also smaller than that in sea rescue.

Finally, from the perspective of the inheritance of my country's aerospace development, after more than 30 years of construction, a number of comprehensive ground-based aerospace tracking and control stations have been established in the country, which can provide better tracking and control support for the return of manned spacecraft; my country has successfully launched a number of recoverable satellites, all of which have successfully landed in the designated recovery area in the Sichuan Basin.

China Aerospace Lunar Exploration Project

Did you know? my country's lunar exploration research has pushed back the moon's "death time" by 1 billion years!

The moon is like a person's life. It goes through birth, infancy, adolescence, middle-aged and old age, and eventually aging and death. "Death" here means that the energy inside the moon has been exhausted and it has no vitality. However, it still rotates and revolves around the earth.

So when did the moon "die"? Previously, the scientific community believed that the moon died 3 billion years ago, but the latest research shows that the moon was still "alive" 2 billion years ago. This conclusion is inseparable from our lunar exploration project's exploration of the back of the moon.

On the far side of the moon, there is a huge basin with a diameter of 2,480 kilometers, the Von Karman crater, which was left after the moon was hit 4 billion years ago. However, due to tidal locking, we have never seen the true appearance of the far side of the moon with our own eyes. Chang'e 4 and Chang'e 5 have made unprecedented progress in our exploration of the far side of the moon.

In December 2018, the Chang'e-4 lander and the Yutu-2 lunar rover were launched by the Long March 3B Improved III launch vehicle (Y30) to the Von Karman crater on the far side of the moon. This was the first time that humans have achieved a soft landing and patrol survey on the far side of the moon, as well as the first time that humans have landed at a high-latitude polar region on the moon and achieved relay communication between the far side of the moon and the earth. However, this time Chang'e-4 did not have the ability to collect soil or rock samples for research.

However, in just two years, Chang'e 5 flew to the moon and successfully completed a series of tasks including landing on the moon, collecting samples, and returning to Earth. Chang'e 5 brought back about 1,721 grams of lunar samples. Through the study of these samples, it was found that there were volcanic eruptions on the moon 2 billion years ago, which successfully postponed the death age of the moon by 1 billion years. This was a huge success.

China Aerospace Beidou Navigation

Beidou Navigation≠Beidou APP

The BeiDou satellite navigation system is an independent, open and compatible giant complex aerospace system built by my country. After its official completion and opening on July 31, 2020, it provides open, free, high-quality navigation, positioning and timing services to the world. The public services provided by the BeiDou system are accessible to the public and available on demand, just like water, electricity and gas, flowing continuously to all walks of life and into the lives of ordinary people. At present, more than 120 countries and regions around the world use the Chinese BeiDou system.

It is important to point out that the BeiDou system is a national treasure. The so-called "BeiDou products" on the market are often just products of a certain company and cannot represent the BeiDou system. The BeiDou system and the manufacturers that develop based on the BeiDou system are two different things, and this must be made clear.

The problem is simple. Although the Beidou system forms a "constellation" in space and releases navigation and positioning capabilities, how to use it is realized by third-party software or hardware, that is, "Beidou products." Therefore, the capabilities of the Beidou system are called by software or hardware, and as for the development of Beidou satellite positioning driving recorders, geological disaster detection instruments, maritime short message communication services and other "products", they are actually realized by specific companies and developers.

At present, the industry application of the Beidou system has been in full swing in the fields of transportation, agriculture, forestry and fishery, hydrological monitoring, meteorological observation and reporting, communication time system, power dispatching, public safety, etc., and has produced significant economic and social benefits. For example, in the field of transportation, the corresponding terminals using the Beidou navigation and positioning capabilities can provide a real, real-time and effective "cargo track flow", which helps to achieve efficient "cargo matching".

Comprehensive sources: China Aerospace Science and Technology Network, People's Daily Online, etc.