Space race: China sent two “dual” use VLEO satellites

China has begun building its own VLEO constellation, i.e., very low orbit, for military (espionage) and commercial use.

According to the China Aerospace Science and Technology Corporation (CASC), developer of the constellation, the satellites will target the global market and compete with leading international commercial remote sensing satellites operated by vendors such as the U.S.-based Maxar and Europe's Airbus.

China Siwei is planning to build 28 RS commercial satellites system before 2025, with 16 high resolution(0.2-0.3m resolution) optical satellites, 4 wide-width (0.7m resolution + 100km swath width) optical satellites and 8 SAR(0.5m resolution) satellites to obtain the capacity of high resolution, wide-width, various sensors, fast receiving, and global coverage.

CASC is a key player in China's defense industry, launching the first four of 300 planned VLEO satellites in 2024 that will orbit at altitudes between 150 and 300 km by 2030.

The constellation supports maritime traffic monitoring and law enforcement surveillance and can also obtain high-resolution images of disaster-stricken areas after floods, fires and earthquakes.

In the evolving landscape of satellite imagery for aerospace and defense, the strategic importance of very low Earth orbit is becoming increasingly apparent. In particular, satellites flying at half the altitude of traditional low Earth orbit (LEO) satellites-typically 250 to 350 km-are twice as close to the action on the ground and therefore better able to observe it. The ability to position satellites closer to Earth has opened up new possibilities for military and intelligence operations in particular.

A Long March-2C carrier rocket placed the pair of satellites, Siwei Gaojing-1 03 and Siwei Gaojing-1 04, into their predetermined orbit on Feb. 27. Last Saturday, ground stations received the first satellite data transmitted by the two satellites, with images characterized by clear details of objects on the ground, realistic colors and rich layers.

On Feb. 27, China launched a Long March-2C carrier rocket that carried two satellites into space. The rocket blasted off at 3:08 p.m. (Beijing Time) from the Jiuquan Satellite Launch Center in northwest China and sent the pair of satellites, Siwei Gaojing-1 03 and Siwei Gaojing-1 04, into their preset orbit.

It was the 561st flight mission of the Long March series of rockets.

According to Beijing, these satellites will have commercial use for remote sensing with the highest spatial resolution and geometric accuracy in China, a CASC official said.

Such satellites are equipped with ultra-agile control technology that enables high-definition “anti-shake” images.

In addition, the satellites adopt real-time camera line-of-sight monitoring technology, establishing sub-arc-second level accuracy between the camera and the satellite, which allows the positioning accuracy of unsupervised images to reach the international advanced level, CASC says.

Siwei's satellite network, which currently includes 9 satellites in space, includes 28 satellites, including 16 high-resolution optical satellites, 4 wide-field optical satellites and 8 synthetic aperture radar (SAR) satellites. The constellation could be expanded to 56 satellites in the future, depending on market demand.

China Siwei is developing an advanced SuperView Neo commercial satellite system, which includes at least 28 satellites dividing into 3 series. SuperView Neo-1 aims to provide 20 to 30 cm optical images. SuperView Neo-2 can provide customers SAR images with up to 50 cm resolution. SuperView Neo-3 can acquire the wide swath optical images with resolution better than 1 meter. The system will significantly enhance the precision and efficiency of global geospatial information services, and help customers to make decisions with confidence.

China has already deployed a couple of satellite constellations for remote sensing from space.

The Jilin-1 constellation, which saw the launch of the first group of satellites in October 2015, now has more than 117 satellites and can observe any point on the globe about 40 times a day.

The constellation can cover the world six times a year and the whole of China 24 times a year. Its operator Chang Guang has partnered with more than 130 foreign users to provide land survey services, urban construction surveys, agriculture and forestry.

In addition, China has put 12 satellites into orbit to form its largest commercial radar remote sensing constellation, Nuwa, named after the Chinese goddess who is said to be the creator of mankind. The Nuwa project aims to create an interconnected platform with 114 satellites to enable a larger hybrid SAR constellation.

The Chinese remote sensing satellite constellation also includes the Gaofen series Earth observation satellite.