Long March 2D, Solar Observatory, ASO-S

Yaogan 37 & Shiyan 22A/B | Long March 2D

Liftoff Time
January 13, 2023 — 7:00 UTC | 15:00 BJT
Mission Name
Yaogan 37 & Shiyan 22A/B, a reconnaissance satellite and two experimental satellites
Launch Provider
(What rocket company launched it?)
China Aerospace Science and Technology Corporation (CASC)
(Who paid for this?)
Probably the Chinese government, given the nature of the payloads
Long March 2D Y73
Launch Location
Site 9401, SLS-2, Jiuquan Satellite Launch Center, China
Payload mass
Where did the spacecraft go?
A circular low-Earth orbit (LEO), at ~515 km (~320 mi) and 43.2 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 in Inner Mongolia, about 60 km (~360 mi) southeast of Wuhai
Did they attempt to recover the fairings?
No, fairing recovery is not a capability of the Long March 2D
Were these fairings new?
Yes, and the fairings probably crashed into the ground at the Shaanxi province, about 50 km (~30 mi) northwest of Yulin
This was the:
– 8th orbital launch attempt of 2023
– 4th Chinese launch of 2023
– 3rd launch provided by CASC of 2023
– 1st launch of a Long March 2D of 2023
– 72nd successful launch of a Long March 2D
– 73rd launch of a Long March 2D
– 461st mission of a rocket from the Long March family
Where to watch
Unofficial launch summary

How Did It Go?

Patch, Long March 2D, Yaogan 37, Shiyan 22A, Shiyan 22B
Mission patch (credit: CASC)

The China Aerospace Science and Technology Corporation (CASC) successfully launched the Long March 2D Y73 vehicle, which carried the Yaogan 37 reconnaissance satellite, and the Shiyan 22A (SY-22A) and Shiyan 22B (SY-22B) experimental satellites into a 515 km (~320 mi) circular low-Earth orbit at 43.2 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 Are The Yaogan 37 & Shiyan 22A/B?

Official statements indicate these three satellites’ purpose is on-orbit verification tests of new technologies such as space environment monitoring.

Yaogan Satellites

As with most reconnaissance satellites, very few specifics of the actual satellites are known. However, the Chinese government has released some information about the Yaogan constellation. Currently, there are ~100 Yaogan satellites in a variety of orbits, ranging from 35° to 100° and orbital altitudes from 480 km circular orbits to 1,200 km eccentric orbits.

The Yaogan constellation is a Chinese reconnaissance constellation. According to Chinese media, the satellites are used for scientific experimentation, surveying land, assessing crop yields, and monitoring disasters. However, the satellites are likely also used for reconnaissance operations by the Chinese Ministry of Defense.

Particularly about the Yaogan 37 in this launch, the Shanghai Academy of Spaceflight Technology (SAST) was responsible for its manufacturing, according to official reports.

Yaogan section adapted from Yaogan 36-03’s article authored by Trevor Sesnic
Yaogan 37, Shiyan 22A, Shiyan 22B
Possible looks of the three satellites in this launch, as they appeared in the red screen the Chinese typically show after a successful launch (credit: CASC)

Shiyan Satellites

China’s aerospace industry has a number of prolific programs aimed at improving applied technologies in this field. The Shiyan 22A and Shiyan 22B satellites are indeed part of a series of spacecraft of the same general 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 22A and Shiyan 22B

Not much has been disclosed about these payloads, so we have to rely on the explanations in the previous paragraphs. However, Chinese authorities have reported that SAST developed the SY-22A. On the other hand, Shiyan 22B’s payload development was a responsibility of Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences (CAS). Its platform’s manufacturer was private company Minospace.

Moreover, both Shiyan satellites appear to be for civilian use, and carry optical instruments to perform their tasks in space. CASC gave further precision, stating that Shiyan 22A will see use for land surveys, urban planning, disaster prevention, and mitigation. In turn, Shiyan 22B will have applications such as haze detection, water pollution monitoring, crop growth observation, and land resource surveys.

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 past.

DateLaunch VehicleMission Name
April 8, 2021 – 23:01 UTCLong March 4BShiyan 6-03
November 24, 2021 – 23:41 UTCKuaizhou-1AShiyan 11
December 23, 2021 – 10:12 UTCLong March 7AShiyan 12-01 & 02
January 17, 2022 – 02:35 UTCLong March 2DShiyan 13
September 24, 2022 – 22:55 UTCKuaizhou-1AShiyan 14 & 15
September 26, 2022 – 23:50 UTCLong March 6Shiyan 16A/B & 17
October 29, 2022 – 1:01 UTCLong March 2DShiyan 20C
December 12, 2022 – 08:22 UTCLong March 4CShiyan 20A & 20B
December 16, 2022 – 6:17 UTCLong March 11Shiyan 21
December 29, 2022 – 4:43 UTCLong March 3/B/EShiyan 10-02
List of the latest 10 Shiyan launches

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.”

Long March 2D Y16 launching the Venezuelan VRSS-1 satellite
Long March 2D launching VRSS-1 (credit: cropped from Cristóbal Alvarado Minic)
Stage quantity2 (3, optional)
Length [m]41.06
Liftoff mass [t]250
Mass to LEO [kg]3,700
Mass to SSO [kg]1,300
FuelUDMH (all stages)
OxidizerN2O4 (all stages)
Basic specifications of the Long March 2D orbital rocket

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 73, The Present CZ-2D

Official reports inform that the placement of the satellites inside the fairing was a first for the Long March 2D rockets. That is, the payloads assumed a series-parallel configuration presumably with YG-37, the main passenger, on top. On the other hand, an auxiliary structure ensured parallel deployment of the Shiyan 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.

Mass [t]
Simplified comparison of the Long March 2D’s first and second stages.

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.

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