Featured image credit: 空天逐梦
Liftoff Time | October 29, 2022 ~ 1:01 UTC | 09:01 BJT |
|---|---|
Mission Name | Shiyan 20C, an experimental satellite |
Launch Provider | China Aerospace Science and Technology Corporation (CASC) |
Customer | Probably the Chinese government, given the nature of the payload |
Rocket | Long March 2D Y72 |
Launch Location | Site 9401, SLS-2, Jiuquan Satellite Launch Center, China |
Payload mass | N/A |
Where did the spacecraft go? | A circular low-Earth orbit (LEO), at ~800 km (~495 mi) and 60.0 degrees inclination |
Did they attempt to recover the first stage? | No, first stage recovery is not a capability of the Long March 2D |
Where did the first stage land? | The first stage crashed into the ground at the Gansu province, southeast from the launch site |
Did they attempt to recover the fairings? | No, fairing recovery is not a capability of the Long March 2D |
Were these fairings new? | Yes |
This was the: | – 147th orbital launch attempt of 2022 – 47th Chinese launch of 2022 – 40th launch provided by CASC of 2022 – 12th launch of a Long March 2D of 2022 – 68th successful launch of a Long March 2D – 69th launch of a Long March 2D – 445th mission of a rocket from the Long March family |
Where to watch | Unofficial launch summary |
How Did It Go?
The China Aerospace Science and Technology Corporation successfully launched the Long March 2D Y72 vehicle, which carried the Shiyan 20C (SY-20C) experimental satellite into a 800 km (~495 mi) circular low-Earth orbit at 60 degrees inclination. Liftoff took place from Site 9401, otherwise known as South Launch Site 2 (SLS-2), at the Jiuquan Satellite Launch Center, in Inner Mongolia, China.
What Is The Shiyan 20C?
China’s aerospace industry has a number of prolific programs aimed at improving applied technologies in this field. The Shiyan 20C satellite is indeed part of a series of spacecraft of the same designation. These certainly play a role in the mentioned search for progress. Particularly, this fact is highlighted by the Chinese word used for their name — Shiyan, or SY for short — which, some experts point out, should be translated as “pilot” or “trial.” However, these satellites are more commonly mentioned as “experiment,” a more widely used translation.
Other series aiming to achieve similar goals are the Shijian, or SJ — best practice, put into practice — and the Chuangxin, or CX — innovation. Both SJ and SY payloads have been contributing for decades now to the China High-resolution Earth Observation System (CHEOS). Apparently, though, a distinction can be made between those last two, as the Shijian sats have favored more radar and infrared payloads. On the other hand, Shiyan have been more focused on Earth-observation satellites.
In order to further differentiate the SY from the SJ, the latter are probably testing, or putting into practice, more mature technologies. These could imply a lower failure ratio, when compared to the Shiyan more experimental spacecraft. Similarly, the Chuangxin might also find themselves in an early condition.
Shiyan 20C
Not much has been disclosed about this payload, so we have to rely on the explanations in the previous paragraphs. Chinese authorities have reported that the Institute of Microsatellite Innovation, a part of the Chinese Academy of Sciences (CAS) developed the SY-20C. Possibly, its internal designation is CX-3C. Additionally, official authorities reported that this satellite will perform in-orbit verification and testing of new technologies for the monitoring of the space environment.
At the time of launch, the A and B satellites of the series still remained a mystery. However, the Long March 4C launched Shiyan 20A/B at a later time.
Other Shiyan Launches
As previously mentioned, these satellites are part of a larger group of “pilot” payloads. In the following table you can find some other Shiyan spacecraft that were launched in the recent past.
| Date | Launch Vehicle | Mission Name |
| April 8, 2021 – 23:01 UTC | Long March 4B | Shiyan 6-03 |
| November 24, 2021 – 23:41 UTC | Kuaizhou-1A | Shiyan 11 |
| December 23, 2021 – 10:12 UTC | Long March 7A | Shiyan 12-01 & 02 |
| January 17, 2022 – 02:35 UTC | Long March 2D | Shiyan 13 |
| September 24, 2022 – 22:55 UTC | Kuaizhou-1A | Shiyan 14 & 15 |
| September 26, 2022 – 23:50 UTC | Long March 6 | Shiyan 16A/B & 17 |
What Is The Long March 2D?
Developed and manufactured by the Shanghai Academy of Spaceflight Technology (SAST) — based on the Long March 4A — the two-stage Long March 2D purpose was to serve the Sun-synchronous orbit (SSO) and LEO market segments, particularly in the lower range of the medium-lift launch vehicles. Furthermore, it is possible to find it mentioned in its short form “LM-2D,” or by its Chinese name “Chang Zheng 2D,” or abbreviated “CZ-2D.”
| Characteristic | Value |
| Stage quantity | 2 (3, optional) |
| Length [m] | 41.06 |
| Liftoff mass [t] | 250 |
| Mass to LEO [kg] | 3,700 |
| Mass to SSO [kg] | 1,300 |
| Fuel | UDMH (all stages) |
| Oxidizer | N2O4 (all stages) |
Originally provided with the type-A fairing — 2.90 m in diameter — a larger new one was later offered to customers — type-B, 3.35 m in diameter. Further developments included a second stage’s attitude control motors, and a passivation and deorbiting system for this same stage.
In spite of lifting off mainly from the launch center in Jiuquan, there have been Long March 2D rockets launching from the Taiyuan and the Xichang ones. Derived from the flight-proven technology of the Dong Feng 5 ICBMs, it only suffered a partial failure on December 28, 2016, otherwise keeping a flawless record since its maiden flight on August 9, 1992.
Yao 72, The Present CZ-2D
Interestingly, since this flight’s requirements were quite demanding, the Long March 2D Y72 rocket underwent the removal of its second stage’s reaction control system. Instead, the vernier engines had to step in to provide these capabilities. As a result, the launch vehicle lost about 100 kg (~220 lb), allowing it to reach a relatively high orbit, carrying the presumably heavy spacecraft.
Deorbiting The Second Stage
Recent in-flight tests of a sail for increasing the orbital decay of the second stage of the Long March 2D have been reported for Yaogan 35 launches. That is, at least, apparently valid for Groups 02, 03, and 04. Such a device is a Chinese effort in reducing space debris generation.
Stages of the Long March 2D
First Stage
Four YF-20 engines work together to power the first stage, running under a gas generator cycle, as well as using hypergolic propellants (as already mentioned). As a whole, this group’s designation is YF-21C, having an ISP of 260 s at sea level. The comparative table below gives further information on the stage.
Second Stage
When adapted to a vacuum environment, where the second stage operates, the YF-20 engines are designated as YF-22. These feature a thrust of ~742 kN and an ISP of 300 s. Vernier engines give stage attitude control capabilities when the main engine does not gimbal. One such vernier is the YF-23, generating ~47 kN of thrust, as well as presenting an ISP of 289 s. These two engines are part of what is called the YF-24 engine, which is solely fed the hypergolic propellants listed before.
| Stage Number | Length [m] | Diameter [m] | Propellant Mass [t] | Engine Name | Thrust [kN] |
| 1 | 27.91 | 3.35 | 182.0 | YF-21C | 2,961.6 |
| 2 | 10.90 | 3.35 | 52.7 | YF-24C | ~789.1 |
Third — Optional
The China Academy of Launch Vehicle Technology (CALT) is responsible for having developed the Yuanzheng (YZ) upper stage. Adapted to ride atop the Long March 2D — its third version, YZ-3 — it adds restarting capabilities, allowing for higher energy final orbits, or circularization maneuvers, as a result. To do this, the stage generates 6.5 kN of thrust, using the same two previously mentioned hypergolic propellants.
Yuanzheng 3 flew only once: on December 29, 2018, stacked onto the Long March 2 Y35, and launching Yunhai-2 satellites and Hongyan-1.
