Long March 8

The Long March 8 ( Chinese  长征八号 , Pinyin Changzheng Bahao shortly CZ-8 ) is a in the China Academy of Launch Vehicle Technology under development launcher of the Long March series. A first launch of the rocket is planned for 2020. In a later version - similar to the American Falcon 9 - it will be partially reusable .

construction

The Changzheng 8, a two-stage rocket with two additional boosters , follows the modular principle introduced with the Changzheng 5 launch vehicle family in 2002. Its first stage is almost identical to the first stage of the medium-weight launch vehicle Changzheng 7 or the K-3 booster of the Changzheng 5, complete with the two YF-100 engines developed for this family of rockets . The second stage corresponds to the third stage of the Changzheng 3A , with a diameter of 3 m and two YF-75 engines . Two-stage solid fuel rockets with a diameter of 2 m and a thrust of 120 kN were planned for the two boosters in February 2017, which the Academy for Solid Rocket Engine Technology was currently working on. But then they switched to the K-2 boosters of the Changzheng 7, successfully launched on June 25, 2016 and April 20, 2017, with a diameter of 2.25 m and each with a YF-100 engine with liquid oxygen and rocket kerosene as fuel.

Development history

The modular design shortened the development time considerably. During the annual plenary session of the Chinese People's Political Consultative Conference , Liang Xiaohong (梁小虹), CPPCC member for the China Science and Technology Association (中国科学技术协会) and works council chairman of the China Academy of Launch Vehicle Technology , on March 7, 2015, revealed that his company was working on a launcher based on the existing systems, already called "Changzheng 8" at that time, which was supposed to close the Chinese gap in sun-synchronous orbits (at that time China could only transport payloads of up to 2 t into such orbits). In September 2016, a model of the new rocket was shown for the first time at an exhibition on the occasion of the annual general meeting of the Association for Science and Technology in Xi'an - Li Hong (李洪, * 1964), the then chairman of the CALT board, was the association's deputy chairman . At the time, the Changzheng 8 was only presented as an environmentally friendly rocket - the second stage uses liquid hydrogen as fuel - with which it was now possible to carry a payload of 3 - 4.5 t into a sun-synchronous orbit, which means a high degree of control precision the missile required.

Already after the Falcon 9 flight 20 on December 22, 2015, in which SpaceX was able to bring the first stage of a rocket safely back to earth and land it vertically, many people in China asked whether one should not also use recyclable rockets. In 2017, Lu Yu (鲁 宇), chairman of the science and technology commission at CALT (a kind of "board of directors") told the press that the company was currently working on two methods: vertical landing with its own engine and parachute landing. At that time, CALT had already carried out practical tests on both approaches. In November of that year, the decision was made to land vertically. At a conference on April 24, 2018, Long Lehao ​​(龙 乐 豪, * 1938), responsible for all Changzheng missiles at CALT, explained that they are already working on a partially reusable missile based on the Changzheng 8, which, similar to on the American Falcon 9, a stage with its own engine could land vertically. On that occasion, Long Lehao ​​announced the maiden flight of a reusable Changzheng 8 for 2020 at the earliest. At a lecture at Beijing University in early July 2018, he then presented a concept in which the two boosters of the Changzheng 8 remained on the first stage and landed together with it. He scheduled the maiden flight of this version for 2021.

Mission profile

By its relatively small diameter, the Changzheng 8 from both the can Wenchang Satellite Launch Center as well as from the Jiuquan Satellite Launch Center started from. It is currently (2020) primarily intended to bring payloads of up to 5 tons (mainly earth observation satellites ) into a sun-synchronous orbit at an altitude of 700 km and 7.6 tons into low earth orbits . The orbit of sun-synchronous satellites is usually inclined by about 90 ° - 99 ° to the equator, it is more or less a polar orbit . China's northernmost cosmodrome, Jiuquan, is more suitable for these missions, as less earth rotation has to be compensated for when taking off in a north (or south) direction . For the other orbits, Wenchang on the island of Hainan , in the very south of China, is more suitable, as there can be started in an easterly direction with the additional thrust from the earth's rotation. The rocket should consist of standardized components and be manufactured relatively quickly; it is supposed to leave the factory about 12 months after the customer signs the contract. The preparations for the launch on the cosmodrome are estimated at around 10 days. The China Academy of Launch Vehicle Technology announced that it will initially carry out around a dozen starts per year with the Changzheng 8, and later more than 20 starts per year. Since the basic version of the rocket, which is scheduled to make its maiden flight in 2020, works with detachable boosters, it is also known as the "combined type" (组合 型, Zǔhé Xíng ).

In the reusable variant (改进型, Gǎijìn Xíng "improved type"), the first stage, after it has separated from the second stage, should return to earth and land on an unmanned floating landing platform in the sea. Like the Falcon 9, it has four grid fins for controlling the descent through the atmosphere and four fold-out landing legs. A video animation of a CZ-8 flight published on January 18, 2020 shows that the two side boosters remain connected to the first stage throughout the flight, as in the concept presented by Long Lehao ​​in July 2018. Since the boosters are so to speak fused with the core stage, this variant of the rocket is also known as the "fused type" (融合 型, Rónghé Xíng ) or CZ-8R . The support arms on the boosters that were planned to point away from the core stage in 2018, i.e. a landing on six legs, are no longer planned. In November 2017, the Academy for Launch Vehicle Technology assumed that the second stage would also land again with its own engine by 2030, thus making the rocket completely recyclable.

Technical specifications

model	CZ-8
stages	2
height	50.3 m
diameter	3.35 m
Takeoff mass	356 t
Start thrust	4800 kN
payload	5 t SSO 7.6 t LEO 2.8 t GTO
1st stage (K-3-1)
height	26 m
diameter	3.35 m
Engine	2 × YF-100 with 1200 kN takeoff thrust each
fuel	liquid oxygen and rocket kerosene
Booster (2 × K-2-1)
height	26.5 m
diameter	2.25 m
Engine	1 × YF-100 with 1200 kN takeoff thrust each
fuel	liquid oxygen and rocket kerosene
2nd stage (H-3-2)
height	12.4 m
diameter	3 m
Engine	2 × YF-75 reignited with 78 kN vacuum thrust each
fuel	liquid oxygen and liquid hydrogen

Individual evidence

1. ^ ^{A b} Andrew Jones: China prepares to launch new rockets as part of push to boost space program . Space.com, February 14, 2020.
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8. ^ ^{A b} Andrew Jones: China to launch new Long March 8 rocket by end of 2018 . GBTimes, February 27, 2017.
9. ↑ 火箭 院 院长 李洪 在 第十 八届 中国 科协 年 会上 展示 航天 60 年 科技 成就. In: calt.com. September 30, 2016, accessed February 16, 2020 (Chinese). 
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11. ↑ 2020 长 八 首飞 、 2030 重型 火箭 首飞 、 2040 核动力 穿梭机 重大 突破 …… 未来 30 年 中国 火箭 发展 重磅 干货 都 在 这. In: calt.com. November 16, 2017, accessed February 17, 2020 (Chinese). 
12. ↑ 谢瑞强: 长征 八号 火箭 2020 年 首飞 ， 国产 重复 使用 火箭 可 期. In: tech.163.com. November 6, 2018, accessed February 16, 2020 (Chinese). 
13. ↑ China is planning a rocket with a payload of 140 tons. In: fliegerrevue.aero. July 9, 2018, accessed February 16, 2020 . 
14. ↑ 谢瑞强: 长征 八号 火箭 2020 年 首飞 ， 国产 重复 使用 火箭 可 期. In: tech.163.com. November 6, 2018, accessed February 16, 2020 (Chinese). 
15. ↑ 胡 喆: 长征 八号 运载火箭 芯 二级 氢氧 发动机 高空 模拟 试验 成功 预计 明年 首飞. In: xinhuanet.com. December 2, 2019, accessed February 17, 2020 (Chinese). 
16. ↑ 航空 知识 365: 想看 现场 胖 5 发射 吗？ 预告 2020 年 中国 航天 发射 有 这些 重头戏. In: k.sina.cn. February 18, 2020, accessed April 30, 2020 (Chinese). 
17. ↑ China to make more than 40 space launches in 2020. In: cctvplus.com. January 18, 2020, accessed on February 16, 2020 . 
18. ↑ 2020 长 八 首飞 、 2030 重型 火箭 首飞 、 2040 核动力 穿梭机 重大 突破 …… 未来 30 年 中国 火箭 发展 重磅 干货 都 在 这. In: calt.com. November 16, 2017, accessed February 17, 2020 (Chinese). 
19. ↑ 长征 八号. In: m.calt.com. Retrieved February 16, 2020 (Chinese). 
20. ↑ 胡 喆: 长征 八号 运载火箭 芯 二级 氢氧 发动机 高空 模拟 试验 成功 预计 明年 首飞. In: xinhuanet.com. December 2, 2019, accessed February 17, 2020 (Chinese).