The reporter learned from the National Space Administration that at 12:37 on December 22, the first flight test of China’s independently developed new generation medium-sized carrier rocket, Long March 8, was successfully carried out at China’s Wenchang space launch site. The rocket flew normally and the test was a complete success.

The Long March 8 launch vehicle fully inherits the technical achievements of Long March 5 and Long March 7 launch vehicles. It adopts non-toxic and pollution-free propellant, with the diameter of the first core stage of 3.35 meters, the diameter of the second core stage of 3 meters, the diameter of the fairing of 4.2 meters, and is bundled with two boosters with a diameter of 2.25 meters. The total length is about 50.3 meters, the take-off mass is about 356 tons, and the 700 km solar synchronous orbit carrying capacity is not less than 4.5 tons, which fills the gap in China The 3-to 4.5-ton carrying capacity of positive synchronous orbit is blank, which is of great significance for accelerating the upgrading of launch vehicles. It will form a new generation of launch vehicles with large, medium and small carrying capacity and reasonable layout, together with Long March 5, Long March 6, Long March 7 and other non-toxic and pollution-free launch vehicles.

The five experimental satellites carried by the Long March 8 launch vehicle in its first flight have accurately entered the predetermined orbit. The relevant satellite payload will carry out on orbit verification of microwave imaging and other technologies, and carry out experiments and applications of space science, remote sensing and communication technologies.

In 2017, the Long March 8 launch vehicle project was approved by the National Space Administration and organized for implementation. The China Academy of launch vehicle technology of China Aerospace Science and Technology Group Co., Ltd. is responsible for the overall development of the launch vehicle system, and the China satellite launch and control system department is responsible for the organization and implementation of the flight test. The mission is the 356th launch of the long march series of launch vehicles.

Long March 8 is a new type of launch vehicle designed for the sun synchronous orbit, which can further improve the type spectrum of China’s launch vehicles and meet the requirements of high-density launch missions in the future.

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According to CCTV news, at about 12:37 on December 22, 2020, the first flight test of China’s independently developed new generation medium-sized carrier rocket, Long March 8, was successfully carried out at China’s Wenchang space launch site. The rocket flew normally and the test was a complete success.

Long March 8 is a new type of launch vehicle designed for the sun synchronous orbit. The carrying capacity of the sun synchronous orbit is about 4.5 tons, that of the geostationary transfer orbit is about 2.5 tons, and that of the low earth orbit is about 7.6 tons.

The Long March 8 launch vehicle is a two-stage and a half configuration with two boosters. Two yf-100 engines with 8-ton thrust are used in the first stage of the rocket. The second stage of the rocket adopts two yf-75 liquid hydrogen and liquid oxygen engines with 8-ton thrust, which has the ability of secondary starting.

It is reported that the long march eight is developed according to the idea of modularization, serialization and combination, fully absorbing the achievements of the in service and new generation of launch vehicles, with good inheritance, economy, advanced nature and adaptability, which can further improve the new generation of launch vehicle spectrum, meet the needs of the future low and high orbit, and can be used to replace the Long March two series in the future. And the Long March 4 series.

The reporter learned from the National Space Administration that at 12:37 on December 22, the first flight test of China’s independently developed new medium-sized carrier rocket, Long March 8, was successfully carried out at China’s Wenchang space launch site. The rocket flew normally and the test was a complete success.

The Long March 8 launch vehicle fully inherits the technical achievements of Long March 5 and Long March 7 launch vehicles. It adopts non-toxic and pollution-free propellant, with the diameter of the first core stage of 3.35 meters, the diameter of the second core stage of 3 meters, the diameter of the fairing of 4.2 meters, and is bundled with two boosters with a diameter of 2.25 meters. The total length is about 50.3 meters, the take-off mass is about 356 tons, and the 700 km solar synchronous orbit carrying capacity is not less than 4.5 tons. The Long March 8 carrier rocket has filled the gap of 3-4.5 tons carrying capacity in China’s solar synchronous orbit, which is of great significance for accelerating the upgrading of the carrier rocket. It will form a new generation of carrier rocket with large carrying capacity, medium and small layout, together with the Long March 5, long march 6, Long March 7 and other non-toxic and pollution-free carrier rocket.

The five experimental satellites carried by the Long March 8 launch vehicle in its first flight have accurately entered the predetermined orbit. The relevant satellite payload will carry out on orbit verification of microwave imaging and other technologies, and carry out experiments and applications of space science, remote sensing and communication technologies.

In 2017, the Long March 8 launch vehicle project was approved by the National Space Administration and organized for implementation. The China Academy of launch vehicle technology of China Aerospace Science and Technology Group Co., Ltd. is responsible for the overall development of the launch vehicle system, and the China satellite launch and control system department is responsible for the organization and implementation of the flight test. The mission is the 356th launch of the long march series of launch vehicles.

More news:

High altitude wind: the air “barrier” that rocket launch must pass

In the eyes of many people, every launch of China’s aerospace is a sure thing. In fact, rocket launching is a high-risk complex system engineering, which is easily affected by various factors, including lightning, temperature, wind and other weather factors. Among many weather factors, the influence of high altitude wind on launch is the most prominent.

The upper wind is generally 4 to 20 kilometers above the ground. Pan Hao, chief designer of changzheng-8 rocket control system of China Aerospace Science and Technology Group rocket academy, said: “during the flight, the rocket will pass through the windy area and suffer strong airflow impact.” He explained that when a person is riding a bicycle, if there is a sudden strong wind blowing from the side, he will be deflected. In space, this crosswind is much stronger than the wind we perceive on land, which will affect the attitude of the rocket. If the wind speed is too high, it may also cause the rocket body bending deformation, damage the rocket structure and even lead to disintegration. For rockets, the high-altitude wind is like a “checkpoint” in the air, which must be broken through to achieve success.

In order to make the rocket “break through” smoothly, it is necessary to observe and forecast the high-altitude wind before launch, adjust the launch time when necessary, and avoid the bad wind conditions. Last year, the first commercial launch of American Falcon heavy rocket was delayed because of high-altitude wind. In fact, the launch of the Long March 8 rocket almost encountered high-altitude wind.

“The launch time we aimed at at at the beginning was earlier than the actual launch time, but just one day before the launch, we predicted that the high-altitude wind over the launch site was abnormal, which was not suitable for launch. Therefore, according to the results of the meteorological chamber of Commerce, we delayed the launch time by two days.” Wu Yitian, deputy chief designer of the Long March 8 rocket of the China Aerospace Science and Technology Group rocket academy, said.

In recent years, the rocket academy has been carrying out relevant research, and has taken a series of measures to reduce the impact of high-altitude wind on rocket launch, including the statistics of wind speed and wind direction over the launch site in recent 10 years, and carrying out targeted design according to the wind direction and wind speed with the maximum probability in the rocket design stage. Before each launch, it is necessary to measure and forecast the high-altitude wind on the launch day, and compensate the high-altitude wind by designing the rocket flight program angle.

Wu Yitian said: “people take umbrellas in the wind. In order to hold the umbrellas steady, they are used to pointing the direction of the umbrellas at the direction of the wind to eliminate the lateral load. The method of high altitude wind compensation is the same as that of parachuting. If possible, the rocket’s longitudinal axis points to the direction of the rocket’s velocity relative to the earth’s atmosphere, so that the angle between the rocket’s longitudinal axis and the direction of the rocket’s velocity relative to the earth’s atmosphere is zero. ” However, this method can only be used after the rocket takes off at a certain speed, and cannot be added suddenly.

In the development of Chang-8 rocket, some new methods are adopted, such as the method of autonomous anti-jamming control. Pan Hao said: “this allows the rocket to identify and compensate for interference while flying. That is to say, after the rocket feels the wind blowing, it can produce corresponding actions to weaken the wind interference. ” However, the launch is special, and the high-altitude wind speed is too high. In order to complete the launch task more safely, we finally choose to adjust the launch time.

Wu Yitian also mentioned: “in the rocket design stage, if the wind field is considered too strictly, the design will be conservative and the rocket structure will be too heavy. On the contrary, the design will be rash and the rocket structure will be light, which will lead to the situation that the wind load on the launch day is high and the launch cannot be carried out. How to better balance the relationship between the two, and better solve the impact of high-altitude wind on the launch, we still need to further explore in the future. “

Editor in charge: PJ

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