China builds large commercial radar satellite constellation

A Chinese commercial radar remote sensing constellation composed of 12 satellites has started its operation, according to PIESAT, a Beijing-based satellite firm.

The announcement came after four PIESAT-2 satellites, which were launched into a 528-kilometer sun-synchronous orbit last week, successfully transmitted high-resolution images and data back to Earth.

The latest satellites joined eight satellites that were previously deployed to space, creating China's largest commercial radar remote sensing constellation: Nuwa, named after the Chinese goddess known as the creator of humanity.

Nuwa's satellites are arranged in three groups. The first group forms a wheel-like configuration, with a main satellite acting as a "hub," surrounded by three auxiliary satellites evenly distributed. The second and third groups were launched over the last two months and are organized in four-satellite, co-orbital, wheel-like formations.

The constellation is now capable of offering global coverage, including coverage in polar and equatorial regions, and can see through clouds and rain, thereby enabling all-weather, constant earth observation with an imaging resolution of up to 1 meter.

"The satellites provide real-time remote sensing with quick response and agile observation capabilities," said Wang Yuxiang, PIESAT's chairman. "They take as little as 20 minutes to transmit data from command to ground reception."

It is expected that by 2025, the Nuwa constellation will have a network of at least 20 satellites to enable a daily revisit interval, with the fastest revisit time reduced to an hour.

The PIESAT team has also used artificial intelligence to enhance image analysis efficiency, realizing the real-time monitoring of millimeter-scale deformations in objects like dams and drainage outlets.