by Xinhua Writers Yu Fei, Quan Xiaoshu
WENCHANG, Hainan, Dec 28 (NNN-XINHUA) – China launched the third Long March-5, the largest carrier rocket of the country, from Wenchang Space Launch Centre, in south China’s Hainan Province on Friday.
The rocket, coded as Long March-5 Y3, blasted off from the coastal launch centre 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.
Wu Yanhua, deputy director of China National Space Administration (CNSA), declared the launch a success.
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 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 China Academy of Launch Vehicle Technology (CALT).
Compared with Long March-5 Y2, the new rocket has more than 200 technological improvements, said Yang Hujun, deputy chief designer of the rocket.
“Over the past two years, the research team solved the problem of the engine and improved the reliability of the rocket,” said Wang Jue, chief commander of the research team.
The rocket is about 57 metres long, equivalent to the height of a 20-story building, with a 5-metre diameter core stage and four 3.35-metre 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 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 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 Centre, the country’s fourth space launch centre, for the Long March-5 and other new-generation carrier rockets. The centre is located on the coast of the tropical island province of Hainan, which avoids possible damage caused by falling rocket remnants.– NNN-XINHUA
