HELSINKI — China sent the classified Yaogan-41 optical satellite towards the geostationary belt Friday using the country’s largest launch vehicle. 

The sixth Long March 5 rocket lifted off from the coastal Wenchang Satellite Launch Center at 8:41 a.m. Eastern (1341 UTC) Dec. 15. The China Aerospace Science and Technology Corp. (CASC) announced launch success around an hour later. 

CASC revealed the payload to be the Yaogan-41 (“remote sensing-41”) satellite. A new, elongated 18.5-meter-long, 5.2-meter-diameter payload fairing shrouded the spacecraft. Previous fairings were 12.3 meters long.

CASC revealed that its China Academy of Space Technology (CAST) subsidiary built Yaogan-41 but provided no images nor further details. State news agency Xinhua described the satellite as an optical remote sensing satellite.

“The satellite will be used in land survey, crop yield estimation, environmental management, meteorological warning and forecasting, and comprehensive disaster prevention and reduction,” Xinhua stated.

Outside observers however assess Yaogan series satellites to be designated for military purposes. The classified nature of the mission suggests Yaogan-41 is for at least partial military use. 

U.S. Space Force space domain awareness cataloged the spacecraft in a 195 by 35,815-kilometer orbit inclined by 19.51 degrees.

The successful launch adds to growing Chinese on-orbit remote sensing capabilities. Should Yaogan-41 take up a position in geostationary orbit, at about 35,786 kilometers above the equator, it will remain in a fixed position relative to the Earth’s surface. This will allow it to conduct continuous observation of the same geographic area. 

This vantage point would allow it to constantly view about one-third of the Earth’s surface. Geostationary optical data would be useful for security, meteorology, climate studies and environmental monitoring purposes.

The mission could be a military follow-up to the civilian Gaofen-4 satellite launched in 2015. The Gaofen-4 GEO optical satellite launched on the much smaller Long March 3B and provides 50-meter-resolution images. 

CAST produces the DFH-5 large satellite bus for GEO communications and remote sensing. Its size and mass requires the Long March 5—which can carry 14,000 kg to GTO—to launch it. The DFH-5 Shijian-20 satellite has a mass of up to 8,000 kilograms. DFH-5 satellites have a lifetime of up to 15 years.

The Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) has produced four-meter-diameter aspheric silicon carbide (SiC) mirrors. SiC mirrors actively serve in space remote sensing.

CIOMP is also involved in developing Xuntian, a Hubble-class space telescope, expected to join the Tiangong space station in orbit in 2025.

In August CASC launched a geosynchronous orbit radar satellite, further adding to its GEO observation capabilities.

The Long March 5 launched for the first time in late 2016. Its second flight in 2017 failed. The rocket was grounded for 900 days as further testing setbacks required a redesign of troublesome turbopumps. The rocket has since successfully launched Shijian-20, China’s first independent interplanetary mission—the Tianwen-1 orbiter and rover mission to Mars—and the 2020 Chang’e-5 lunar sample return mission.

The five-meter-diameter, 874-ton rocket is currently China’s largest. Its 5B low Earth orbit variant constructed the country’s space station. The Long March 5 is also the basis for the under-development Long March 10, which will use upgraded versions of its YF-100 kerosene-liquid engines and three five-meter-diameter cores.

The Yaogan-41 launch followed a day after China sent its experimental reusable spacecraft into orbit for the third time. The spacecraft entered a 333 to 348 kilometer altitude orbit, inclined at 50 degrees.

Friday’s launch was China’s 61st of 2023, with worldwide orbital launches numbering close to 200. Notable Chinese launches include crew and cargo missions to Tiangong, satellite internet test satellites and the first commercial liquid propellant launches.

CASC aimed to launch more than 60 times this year but, with commercial launch providers accounting for 15 launches, appears to be falling someway short of this stated goal. However CASC has not suffered a launch failure since 2020.

Andrew Jones covers China's space industry for SpaceNews. Andrew has previously lived in China and reported from major space conferences there. Based in Helsinki, Finland, he has written for National Geographic, New Scientist, Smithsonian Magazine, Sky...