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China's largest carrier rocket Long March-5 makes new flight

2019-12-30 12:10

Long March-5 Y3 blasts off from Wenchang Space Launch Center in south China's Hainan Province, Dec. 27, 2019. The rocket, coded as Long March-5 Y3, blasted off from the coastal launch center at 8:45 p.m. (Beijing time), carrying the Shijian-20 technological experiment satellite weighing over eight tonnes, the heaviest and most advanced communications satellite of the country. About 2,220 seconds later, the satellite was sent into its planned orbit. (Xinhua/Chen Yehua)

by Xinhua Writers Yu Fei, Quan Xiaoshu

WENCHANG, Hainan, Dec. 27 (Xinhua) -- China launched the third Long March-5, the largest carrier rocket of the country, from Wenchang Space Launch Center in south China's Hainan Province on Friday evening.

 

The rocket, coded as Long March-5 Y3, blasted off from the coastal launch center at 8:45 p.m. (Beijing time), carrying the Shijian-20 technological experiment satellite weighing over eight tonnes, the heaviest and most advanced communications satellite of the country.

 

About 2,220 seconds later, the satellite was sent into its planned orbit.

 

Wu Yanhua, deputy director of the China National Space Administration (CNSA), declared the launch a success.

 

The success of the flight lays the foundation for a series of future space projects for the country including exploring Mars, returning moon samples and constructing its own space station, Wu said.

 

The Shijian-20 satellite will be used to test the key technologies of the DFH-5 platform, China's new-generation large satellite platform, and offer communication and broadcasting service, Wu said.

 

The Long March-5 is a large, two-stage rocket, capable of carrying a payload of 25 tonnes, equivalent to the weight of 16 cars, to low Earth orbit, 14 tonnes to geostationary transfer orbit, eight tonnes to Earth-Moon transfer orbit, or five tonnes to Earth-Mars transfer orbit, over twice the capacity of the current main Long March series rockets. Combined with an upper stage, the rocket is capable of sending probes to explore Jupiter and other planets in the solar system, according to the China Aerospace Science and Technology Corporation (CASC).

 

The Long March-5 made its maiden flight on Nov. 3, 2016 from Wenchang. However, the second large rocket, Long March-5 Y2, suffered a failure, as a malfunction happened less than six minutes after its liftoff on July 2, 2017.

 

The research team has found that the failure was caused by a problem in the engine of the first core stage of the rocket. "We have made improvements to the design, materials and technologies of the engine," said Li Dong, chief designer of the Long March-5 rocket from the China Academy of Launch Vehicle Technology (CALT) under the CASC.

 

Compared with the Long March-5 Y2, the new rocket has more than 200 technological improvements, said Yang Hujun, deputy chief designer of the rocket.

 

The modified engine has undergone more than 10 ground tests lasting over 3,000 seconds in total.

 

"Over the past two years, the research team has solved the problem of the engine and improved the reliability of the rocket," said Wang Jue, chief commander of the research team.

 

The carrying capacity of the Long March-5 rocket equals that of other mainstream large-scale rockets in the global industry, greatly improving China's ability to launch spacecraft and laying the foundation for developing new-generation carrier rockets and heavy-lift launch vehicles, said Wang Xiaojun, head of the CALT.

 

The rocket is about 57 meters long, equivalent to the height of a 20-story building, with a 5-meter diameter core stage and four 3.35-meter diameter boosters. The Long March-5 is much larger than China's previous carrier rockets. It has a takeoff weight of about 870 tonnes and a thrust of over 1,000 tonnes.

 

The four boosters, developed by the Shanghai Academy of Spaceflight Technology under the CASC, shoulder over 90 percent of the takeoff thrust.

 

The rocket uses environmentally friendly fuel, including kerosene, liquid hydrogen and liquid oxygen, rather than highly toxic propellants.

 

It is equipped with eight liquid oxygen/kerosene rocket engines in four strap-on boosters, two liquid hydrogen/liquid oxygen engines in the first stage and two relatively small liquid hydrogen/liquid oxygen engines in the second stage.

 

The weight of the rocket itself only accounts for about 10 percent of the liftoff weight, and the other 90 percent is the weight of the propellants.

 

The research team has made efforts to decrease the weight of the rocket in its design. For instance, the thickness of the rocket shell in some parts is only a few millimeters, according to Li Linsheng, a structural strength analysis designer of the rocket.

 

The temperature of liquid hydrogen is minus 253 degrees centigrade, and the temperature of liquid oxygen is minus 173 degrees centigrade. The maximum temperature of the fuel during combustion in the rocket engine is more than 3,300 degrees centigrade.

 

China built the Wenchang Space Launch Center, the country's fourth space launch center, for the Long March-5 and other new-generation carrier rockets. The center is located on the coast of the tropical island province of Hainan, which avoids possible damage caused by the falling rocket remnants.

 

In the center is the country's largest and most advanced launch pad that is 70 meters tall, equivalent to the height of a 24-story building, and covers an area of 600 square meters, the same size as half a basketball court.

 

2019年12月27日,长征五号Y3火箭在海南文昌航天发射中心发射升空。这枚代号为长征五号Y3的火箭于北京时间晚上8点45分从沿海发射中心发射升空,运载着重达8吨的实践20号技术实验卫星,这是中国最重、最先进的通信卫星。大约2220秒后,卫星被送入预定轨道。(新华社/陈Yehua)


由新华网记者余飞、关晓树等撰写


新华网海南文昌12月27日电(记者王文昌)中国第三次发射长征五号运载火箭,这是中国最大的运载火箭。


这枚代号为长征五号Y3的火箭于北京时间晚上8点45分从沿海发射中心发射升空,运载着重达8吨的实践20号技术实验卫星,这是中国最重、最先进的通信卫星。


大约2220秒后,卫星被送入预定轨道。


中国国家航天局副局长吴艳华宣布这次发射成功。


吴说,这次飞行的成功为中国未来的一系列太空项目奠定了基础,包括探索火星、返回月球样本和建设自己的空间站。


“实践20号”卫星将用于测试我国新一代大型卫星平台——DFH-5平台的关键技术,并提供通信和广播服务。


长征- 5号是一个大型的、两级火箭能够携带有效载荷25吨,相当于16个汽车的重量,低地球轨道,地球同步转移轨道14吨,8吨月转移轨道,或5吨Earth-Mars转移轨道,两倍多的能力当前主要长征系列火箭。根据中国航天科技集团公司(CASC)的说法,与上层火箭结合,火箭能够发射探测器探索木星和太阳系的其他行星。


长征五号于2016年11月3日在文昌进行了首次飞行。然而,第二枚大型火箭长征五号Y2在2017年7月2日发射后不到6分钟就发生故障。


研究小组发现,故障是由火箭第一核心级的发动机问题引起的。中国运载火箭技术研究院长征五号火箭总设计师李东表示:“我们已经在发动机的设计、材料和技术上做出了改进。”


与长征五号Y2相比,新火箭有200多项技术改进,火箭副总设计师杨虎军说。


改装后的发动机已经进行了10多次地面测试,总时间超过3000秒。


“在过去的两年里,研究团队已经解决了发动机的问题,提高了火箭的可靠性,”研究团队的首席指挥官王珏说。


中国运载火箭研究院院长王晓军表示,长征五号运载火箭的运载能力与全球其他主流大型运载火箭相当,大大提高了中国发射宇宙飞船的能力,为发展新一代运载火箭和重型运载火箭奠定了基础。


火箭大约57米长,相当于20层楼高,有一个直径5米的核心级和四个直径3.35米的助推器。长征五号比中国以前的运载火箭大得多。它的起飞重量约为870吨,推力超过1000吨。


这四个助推器是上海航天技术研究院在航天飞行控制中心下开发的,承担了90%以上的起飞推力。


该火箭使用的是包括煤油、液氢和液氧在内的环保燃料,而不是剧毒的推进剂。


它装备有八个液氧/煤油火箭发动机,在四个捆绑式助推器中,两个液氢/液氧发动机在第一级,两个相对较小的液氢/液氧发动机在第二级。


火箭本身的重量只占发射重量的10%,其余的90%是推进剂的重量。


研究小组已经在设计中努力减少火箭的重量。例如,据火箭结构强度分析设计师李林生(音)说,火箭外壳的某些部分只有几毫米厚。


液氢的温度是- 253摄氏度,液氧的温度是- 173摄氏度。火箭发动机燃烧时燃料的最高温度超过3300摄氏度。

 

中国为长征五号和其他新一代运载火箭建造了文昌航天发射中心,这是中国的第四个航天发射中心。该中心位于热带岛屿省份海南的海岸,避免了可能由坠落的火箭残骸造成的损害。


发射中心是中国最大、最先进的发射台,高70米,相当于一座24层建筑的高度,占地600平方米,相当于半个篮球场那么大。

 

原作者: Mu Xuequan 来自: xinhua