|Country of origin||China|
|Used on||Long March rocket family |
(2C · 2D · 3B · 3C · 5 · 7)
|First flight||30 March 2015 |
|Engines||1 × YF-50D|
|Thrust||6.5 kN (1,500 lbf)|
|Specific impulse||315.5 seconds|
4 / UDMH
The Yuanzheng stage enables the Chinese launch vehicles to deploy payloads directly to high-energy orbits such as medium Earth orbit (MEO) and geosyncronous orbit (GSO). Since the Long March third stage cannot restart, it cannot circularize a GSO or GEO orbit from a geosyncronous transfer orbit (GTO). With its restart capability, Yuanzheng has enabled the deployment of satellite pairs for the BeiDou Navigation Satellite System in MEO and communications satellites in GSO. This eliminates the need for the spacecraft to include a liquid apogee engine or an apogee kick motor.
Yuanzheng has a thrust of 6.5 kN (1,500 lbf) with a specific impulse of 315.5 seconds. It uses the storable hypergolic propellants unsymmetrical dimethylhydrazine (UDMH) and dinitrogen tetroxide (N
4), and can perform at least two burns within its rated life of 6.5 hours, sufficient to reach the transfer orbit apogee, and perform the circularization burn from there.
Yuanzheng was presented in a 2013 paper and performed its first mission on 30 May 2015. The debut flight of the Long March 7 in 2016 included an improved version called Yuanzheng-1A that can flexibly deploy multiple payloads into various target orbits. Further variants were later deployed for Long March 5 (YZ-2) in 2016, Long March 2C (YZ-1S) and Long March 2D (YZ-3) in 2018.
|No.||Date (UTC)||Carrier Rocket||Stage Model||Launch site||Mission||Result|
|Long March 3C||YZ-1||Xichang||BDS I1-S||Success|
|Long March 3B||YZ-1||Xichang||BDS M1-S / BDS M2-S||Success|
|Long March 3C||YZ-1||Xichang||BDS M3-S||Success|
|Long March 7||YZ-1A||Wenchang||Inaugural Mission||Success|
|Long March 5||YZ-2||Wenchang||Inaugural Mission||Success|
|Long March 3B||YZ-1||Xichang||BDS-3 M1
|Long March 3B||YZ-1||Xichang||BDS-3 M7
|Long March 3B||YZ-1||Xichang||BDS-3 M3
|Long March 3B||YZ-1||Xichang||BDS-3 M9
|Long March 3B||YZ-1||Xichang||BDS-3 M5
|Long March 3B||YZ-1||Xichang||BDS-3 M11
|Long March 3B||YZ-1||Xichang||BDS-3 M13
|Long March 2C||YZ-1S||Jiuquan||Yaogan 32A, 32B||Success|
|Long March 3B||YZ-1||Xichang||BDS-3 M15
|Long March 3B||YZ-1||Xichang||BDS-3 M17
|Long March 2D||YZ-3||Jiuquan||Yunhai-2 01, 02, 03, 04, 05, 06
|Long March 3B/E||YZ-1||Xichang||BDS-3 M23
|Long March 3B/E||YZ-1||Xichang||BeiDou-3 M21
|Long March 3B/E||YZ-1||Xichang||BeiDou-3 M19
Currently, there is known to be five versions:
- Yuanzheng-1 (AKA YZ-1) (Chinese: 远征一号; pinyin: Yuǎn Zhēng Yī Hào; literally: 'Expedition One'): Initial version used with the Long March 3. It could perform missions of 6.5 hours, make two ignitions, perform one spacecraft deployment operation.
- Yuanzheng-1A (AKA YZ-1A) (Chinese: 远征一号甲; pinyin: Yuǎn Zhēng Yī Hào Jiǎ; literally: 'Expedition One A'): Improved version used with the Long March 7. Improved version with mission life extended to 48hs, capability to perform at least 9 ignitions and ability to do 7 different separation events. It also includes improved thermal control system, guidance algorithms and orbit planning for multiple payload deployment missions. It will be used as the base system for future deep space propulsion stages, space tugs and orbital servicing and debris removal spacecraft.
- Yuanzheng-1S (AKA YZ-1S) (Chinese: 远征一号商业型; pinyin: Yuǎn Zhēng Yī Hào Shāng Yè Xíng; literally: 'Expedition One Commercial Version'): Improved version used with the Long March 2C.
- Yuanzheng-2 (AKA YZ-2) (Chinese: 远征二号; pinyin: Yuǎn Zhēng Èr Hào; literally: 'Expedition Two'): New version used with the 5.2 m (17 ft) Long March 5 upper stage.
- Yuanzheng-3 (AKA YZ-3) (Chinese: 远征三号; pinyin: Yuǎn Zhēng Sān Hào; literally: 'Expedition Three'): New version used with the Long March 2D.
- "New Launch". www.casc11.com (in Chinese). Xi'an Aerospace Propulsion Institute. 2015-07-26. Retrieved 2015-08-02.
- Norbert Bgügge. "Photo Gallery CZ-3CE". B14643.DE. Retrieved 2015-07-25.
- Kun, Ma; Wu, Guo; Song, Guan; Zhibin, Ma; Tongyu, Li (2013). "上面级发展现状及趋势分析" [Development Status and Trend Analysis of Upper Stages]. Missiles and Space Vehicles (in Chinese). No.6 2013 (329): 24–28. doi:10.7654/j.issn.1004-7182.20130606 (inactive 2020-01-04).
- Norbert Bgügge. "YZ-1 space tug". B14643.DE. Retrieved 2015-07-25.[permanent dead link]
- "长征七号首飞成功 空间实验室任务大幕拉开" [Successful maiden flight of the Long March 7 mission Damulakai]. www.spacechina.com (in Chinese). 2016-06-25. Archived from the original on 28 June 2016. Retrieved 2016-06-25.
- "升级版的中国"太空摆渡车"将带来什么?" [What will enable the upgraded space bus?]. www.chinanews.com (in Chinese). 2016-06-25. Retrieved 2016-06-27.
- "远征一号上面级" [Yuanzheng-1 Upper Stage]. www.chinaspaceflight.com (in Chinese). 2016-06-07. Retrieved 2016-06-30.
- "远征一号甲上面级(YZ-1A)" [Yuanzheng-1A Upper Stage (YZ-1)]. www.chinaspaceflight.com (in Chinese). 2016-06-26. Retrieved 2016-06-30.
- "远征二号上面级：今年发射的"长征五号"火箭将启用新研制上面级"远征二号"" [Yuanzheng-2 upper stage: this year's launch of the Long March 5 rocket upper stage will enable the development of new "Yuanzheng-2"]. www.chinaspaceflight.com (in Chinese). 2016-03-30. Retrieved 2016-06-30.