5m S-SAR-01 | Long March 2C

Lift Off Time
October 12, 2022 – 22:53 UTC
October 13, 2022 – 06:53 BJT
Mission Name
5m S-SAR-01 or Huanjing Jianzai 2E (or 2 05)
Launch Provider
(What rocket company launched it?)
China Aerospace Science and Technology Corporation (CASC)
Customer
(Who paid for this?)
The Ministry of Ecology and Environment of the People’s Republic of China (MEE), and
the Ministry of Emergency Management of the People’s Republic of China (MEM)
Rocket
Long March 2C
Launch Location
Launch Complex 9, Taiyuan Satellite Launch Center, Shanxi, China
Payload mass
No greater than 1,000 kg (~2,200 lb)
Where did the satellites go?
A Sun-synchronous orbit (SSO) at 500 km in altitude and 97.4 degrees inclination
Did they attempt to recover the first stage?
No, first stage recovery is not a capability of the Long March 2C
Where did the first stage land?
It crashed on land in central China
Did they attempt to recover the fairings?
No, fairing recovery is not a capability of the Long March 2C
Were the fairings new?
Yes
This was the:
– 65th launch of a Long March 2C
– 6th launch of a Long March 2C of 2022
– 45th Chinese launch of 2022
– 137th orbital launch attempt of 2022
– 443rd launch of a rocket in the Long March family
Where to watch
Unofficial Replay

How Did It Go?

China Aerospace Science and Technology Corporation launched a Long March 2C carrier rocket lofting the 5m S-SAR-01 Earth-observation satellite on October 12, 2022. This launch vehicle lifted-off from the Launch Complex 9, at the Taiyuan Satellite Launch Center, located in the Shanxi province of China. With the rocket having completed its flight nominally, the payload was reported to have reached the targeted orbit. Therefore, the mission has been declared successful.

What Is The 5m S-SAR-01 Satellite?

As an Earth-observation spacecraft, the 5m S-SAR-01 satellite — also known as Huanjing Jianzai 2 05 — will be tasked with disaster prevention and mitigation, as well as resources monitoring and environmental protection, eg water conservancy, agriculture, forestry, among others. “Huanjing” (环境) means environment, and (减灾) “Jianzai”, disaster mitigation, explaining the function of this craft. Additionally, S-SAR stands for Synthetic Aperture Radar, with the “S” indicating the band in which it will operate. “5m,” that is five meters, identifies the resolution of this satellite’s images.

Developed by Shenzhen Aerospace Dongfanghong Satellite Ltd., a subsidiary of CAST, it features two payloads:

  • An S-band Synthetic Aperture Radar (SAR), and
  • An emergency data processing subsystem.
S-SAR-01 front view (credit: CAST)
S-SAR-01, Huanjing Jianzai 2E
S-SAR-01 rear view (credit: CAST)

Operating in the S-band, microwaves, gives an advantage over satellites who operate in other regions of the electromagnetic spectrum. In this way, images of the surface of the Earth can be obtained through clouds, allowing for continued work independently of weather factors. Such a performance is achieved using the large antenna seen in the pictures, which implements a phased array feed combined to an elliptical parabolic reflector — a novelty applied to the S-SAR-01 spacecraft. In a few words, it works by emitting a signal, and then measuring its echo to create images.

Additional improvements on this spacecraft are a better capability for filtering noise — or useless signal — greater data transmission rate, enlarged digital on-board storage, and more accurate image positioning.

Through the implementation of the emergency data processing subsystem, the customer gains access to geometrically corrected images, as well as real-time data regarding water areas, or oil-spillage occurrences, among other services. Thanks to these capabilities, monitoring of disaster zones benefits from a faster and more precise acquisition of vital information.

S-SAR-01, S-Band
S-SAR-01 antenna (credit: CAST)

S-SAR-01’s Bus

A render of the CAST2000 bus from the page of CGWIC
Generic CAST2000 bus (credit: CGWIC)

CAST2000 is a platform developed by the China Academy of Space Technology (CAST), massing up to 600 kg and allowing another 400 kg for payload. It is capable of operating in low, medium, and high-Earth orbit (400 km to 1,200 km), while keeping station and maneuvering. To do this it utilizes hydrazine-fed small engines creating thrust in the range of 1 N ot 5 N. Moreover, this bus is provided with two solar arrays, which generate from 500 W to 2,000 W of power.

Presenting capabilities to swing — needed by some Earth observation payloads — it enables carrying out a wide variety of tasks: Earth observation, technology demonstration, scientific exploration, Earth environment detection, meteorological research and application, communications, navigation, among others.

Other Chinese satellites of this kind have been into orbit before, becoming part of small constellations where optical satellites are grouped together with others obtaining radar images. Namely, the Huanjing Jinazai 1A and 1B (or HJ-1A and HJ-1B for short), which are of the former kind, while the HJ-1C is of the latter. This spacecraft is retiring, which is why its responsibilities will pass to the HJ-2E. A further launch of a HJ satellite is planned for next year: the S-SAR-02, or HJ-2F.

Satellite Type Launch Date Present Orbit
HJ-1A Visible/Infrared imager September 6, 2008 – 03:25 UTC SSO, ~643 km x 97.7°
HJ-1B Visible/Infrared imager September 6, 2008 – 03:25 UTC SSO, ~643 km x 97.7°
HJ-1C Radar imager November 18, 2012 – 22:53 UTC SSO, ~400 km x 97.1°
HJ-2A Visible/hyperspectral imager September 27, 2020 – 03:23 UTC SSO, ~647 km x 98.0°
HJ-2B Visible/hyperspectral imager September 27, 2020 – 03:23 UTC SSO, ~647 km x 98.0°
HJ-2E Radar imager October 12, 2022 – 22:53 UTC SSO, ~500 km x 97.4°
HJ-2F Radar imager Planned Planned
Brief summary of Huanjing Jianzai missions

What Is The Long March 2C?

The Long March 2C is a two-stage medium-lift launch vehicle, with an optional third stage, derived from China’s Long March 2B vehicle. It is able to put up to 3,850 kg into low-Earth orbit, and up to 1,250 kg into geostationary transfer orbit (GTO).

The Long March 2C, SuperView Neo 1-01 & 02 Mission
The Long March 2C (Credit: Xinhua)

Stages of the Long March 2C

First Stage

The first stage has four open cycle YF-20C engines. Each engine runs on dinitrogen tetroxide (N2O4) and unsymmetrical dimethylhydrazine (UDMH), producing 740 kN of thrust each, with a specific impulse (ISP) of 260 s. Overall, the first stage produces 2,960 kN of thrust and carries 182,000 kg of propellant. The first stage is 25.72 m tall, and 3.35 m in diameter.

Second Stage

The second stage runs on a single YF-24E engine, which contains one main YF-22E engine for thrust, and four YF-23C attitude control thrusters. The main engine produces 816 kN of thrust and the attitude control thrusters each produce 47 kN, and both run on N2O4 and UDM. The main engine’s ISP is ~300 s, and the attitude control thrusters have an ISP of 289 s. The second stage is 7.75 m tall, 3.35 m in diameter, and carries 162,700 kg of propellant.

Third stage

The third stage, the Yuanzheng, is a restartable upper stage. The variant used on the Long March 2C is designated YZ-1S. The Yuanzheng allows launch vehicles to deploy their payloads directly into high energy orbits, like medium-Earth orbit (MEO) and geosynchronous orbit (GSO). The stage features one YF-50D engine, which like the first and second stages runs UDMH and N2O4. It provides 6.5 kN of thrust and has an ISP of 315.5 s. The stage can perform at least two burns within its lifespan of 6.5 hours.

Long March 2, the YZ-1S upper stage
The YZ-1S upper stage. (Credit: CALT)

Rocket section by Trevor Sesnic.

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