China launches Advanced Space-borne Solar Observatory

by Adrian Beil

China launched the Advanced Space-borne Solar Observatory (ASO-S) on Chang Zheng 2D. The launch took place on Oct. 8, at 23:43 UTC, and was confirmed a success. It will operate in a 720 km Sun-synchronous orbit and will observe the Sun 24 hours a day.

Furthermore, a CentiSpace payload was launched, and LandSpace updated the public on their design for ZhuQue-2. Also, the Wenchang Commercial Space Port is progressing in construction.

Chang Zheng 2D Launches ASO-S

ASO-S is designed to operate for four years in its Sun monitoring mission and will focus on the observation of the Sun cycle. It masses 888 kg and will carry the nickname “Kuafu-1,” after a giant in Chinese mythology who tried to chase the Sun. This nickname was picked in a public request to name the spacecraft.

It was originally proposed in 1976 as ASTRON-1, which was never fully funded and dropped later. With the establishment of the space science priority program of the Chinese Academy of Science (CAS) in 2011, the plan for a Sun observatory was revisited.

In 2014, it was studied if the payload was feasible, and was green-lighted in April 2016. After that, the assembly of the science instruments began. The assembly and construction of ASO-S concluded in August 2022 as it got the “go” to proceed to launch. 

The team of ASO-S in front of the payload inside the fairing. (Credit: CASC)

ASO-S is equipped with three instruments. The first is a Full-Disc Vector Magnetograph (FMG) which will be used to monitor the magnetic field of the entire Sun. It can operate with a sensibility of 0.5 mT and will mainly be used to observe the photosphere of the Sun, which is the star’s outer shell. The FMG was developed by the Xián Institute of Optics and Precision Mechanics.

As the second instrument, it carries a Hard X-ray Imager (HXI) camera. This camera can take images of solar flares in the area of 30 keV to 200 keV and will be used to predict, monitor, and research solar flares of our Sun. HXI was built by the Purple Mountain Observatory.

The final instrument is a set of three Lymar-alpha Solar Telescopes (LST). These will be used to observe the inner part of the coronasphere of the Sun and solar flares. The three telescopes are the WST, which can monitor white light that is emitted by the Sun, the SDI, which will be able to get pictures of the solar disk, and the SCI, which is a coronagraph for the observation of up to 2.5 solar radii. The LST was developed by the Changchun Institute of Optics, Fine Mechanics and Physics.

The observatory is powered by two movable solar panels which are expected to provide 898 W of power. The maneuvering of the observatory allows for a pointing accuracy of 0.01°, measuring the Sun. It is furthermore equipped with 4 TB of storage and can transmit up to 1 Gbit/s of data to earth. 

For the whole payload, a price of $126 million is quoted. It is planned to have the observatory fully operational before the peak of Sun activity in this cycle, which is expected to happen around 2023/2024. It will be operated by the Purple Mountain Observatory.

CZ-2D on the pad ahead of launch. (Credit: CASC)

As a launch vehicle, the Chang Zheng 2D was chosen. This is already its 10th flight in 2022, which keeps it as the second most launched rocket of the year after the SpaceX Falcon 9. 

It is an orbital-class rocket, manufactured by the Shanghai Academy of Spaceflight Technology (SAST), and consists of two stages. It stands 41 meters tall with a diameter of 3.35 meters and a liftoff mass of 232,250 kg.

Its first stage is powered by four YF-21C engines, and like the whole rocket, fueled by dinitrogen tetroxide and unsymmetrical hydrazine. At liftoff, it has a thrust of 2,961.6 kN. The second stage is powered by a single YF-24C engine, which can provide up to 742.04 kN for the final insertion into orbit. 

For very demanding payloads, it is possible to add a third stage, called the YZ-3. This is very rarely used and was not utilized in this launch.

The launch was conducted from the Jiuquan Satellite Launch Center (JSLC), which was established as a launch and missile test site in 1958. It is the oldest of the four Chinese spaceports.

CentiSpace-1 S5&S6 Launch

The second launch of the week carried the CentiSpace-1 S5&S6 payload on a Chang Zheng 11H. The launch took place on Oct. 7 at 13:10 UTC from the De Bo 3 Barge in the Yellow Sea.

CZ-11H on the barge ahead of the launch. (Credit: CASC)

CentiSpace payloads are satellites made by Future Navigation, a Beijing-based company. They are described as test satellites that are used to monitor the performance of the global navigation system in real time and carry out navigation and inter-satellite laser communication tests.

Down the line, these test satellites are leading into a planned 160-satellite constellation in low Earth orbit (LEO) that will support global navigation and satellite communication. The mass and size of the satellites for today’s mission were not released.

As a launch vehicle, the Chang Zheng 11H (CZ-11H) was used. This solid-based launch vehicle was launched from a barge from the Yellow Sea, as indicated by the “H” at the end of the vehicle’s name, which is used for CZ-11 rockets that are sea-launched. 

The rocket is fully based on solid rocket motors and was the first Chang Zheng rocket to be built in such a way. It was developed by the China Academy of Launch Vehicle Technology (CALT) as a cheap and quick-reaction launch vehicle that can easily be stored and used whenever it is needed. 

During the launch, the vehicle is first ejected upwards from the barge, before igniting its solid rocket motor. It can lift lighter payloads to LEO, with its 700 kg lift capability.

This might not be the last Chang Zheng 11 launch for this year, as the mayor of Yatai City said that he expects three more sea launches before this year’s end. The China Aerospace Science and Technology Corporation (CASC) also confirmed more launches of CZ-11H before the end of the year.

Used for this launch was the De Bo 3 barge, which was used before to launch a set of Gaofen satellites in September 2020. There is another barge, called Tai Rui, which can also support launches of the CZ-11H in the Yellow Sea.

Zhuque-2 Updates

LandSpace, the company that is constructing Zhuque-2 (ZQ-2), recently released a tour of their factory. In this tour, they updated the public on several changes to their ZQ-2, which is in the race to be the first methane-based rocket in space.

ZQ-2 first-stage engine with upgrades on the test stand. (Credit: LandSpace)

While ZQ-2 has not yet flown, hardware for the second and third flights is already being assembled. The factory right now can support up to four TQ-12 engines a month, which would allow for one rocket a month in terms of engine production.

The second stage was also updated, as the company is developing an improved version of the engine, called TQ-15A. This update will remove the vernier engines from the second stage, and equip it with a thrust-vector control range of 4°. The thrust will also be improved and feature restart capabilities for more flexibility on mission profiles. In the future, the company also wants to release footage from its launch facility at Jiuquan.

In a recent update, the company already announced an update to its first-stage engine TQ-12. The TQ-12A will feature a 9% higher thrust and 40 s more specific impulse. This updated engine is already on the test stand and will debut on later flights. It also hints at plans for reusability for the first stage, as they are testing restarting capabilities of the first-stage engine. 

ZQ-2 currently has no public launch date. It is suspected to fly before the end of the year.

Wenchang Commercial Space Port

Over at Wenchang, the commercial space port is making progress, as confirmed by satellite imagery. In September, renderings were shown of the facilities that are constructed to support the growing Chinese commercial rocket launch sector, with not only ZQ-2, but companies like LinkSpace, Galactic Energy, and i-Space producing commercial Chinese launch vehicles.

The Wenchang Satellite Launch Center (WSLC) is a growing spaceport close to Wenchang city that is used more and more for modern Chinese rockets. With its location close to the sea, it is no longer launching over populated areas, compared to other Chinese spaceports. This reduces risks for residents living close to spaceports.

(Lead image: C2-2D lifts ASO-S. Credit: CASC)

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