BEIJING, 31st March, 2023 (WAM) — China launched a Long March-2D carrier rocket into space on Thursday evening carrying a wheel-like formation of four remote sensing satellites, the first formation of its kind in the world.
According to state news agency Xinhua, the satellites of the PIESAT-1 constellation were launched at 6:50 pm (Beijing Time) from the Taiyuan Satellite Launch Centre in northern China's Shanxi Province and then entered a preset orbit.
The in-orbit constellation has formed a lineup like a vehicle wheel. It comprises a primary satellite running at the central "axle" and three supplementary satellites evenly placed in an elliptical "wheel hub" and orbiting the primary satellite. The supplementary trio is located just a few hundred metres from the primary satellite.
The four satellites are equipped with interferometric synthetic aperture radars (InSARs), which are effective tools to measure changes in the land surface.
The InSARs capture two images at different times by reflecting radar signals off a target area on Earth and then have them interfere with each other to produce maps called interferograms, which reveal the ground-surface displacement between the two time periods.
Unlike visible or infrared light, radar waves can penetrate most weather clouds and are equally effective in darkness.
Compared to traditional InSARs, a wheel formation can generate more interference baselines, thus increasing mapping efficiency.
The constellation, mainly used to provide commercial remote-sensing data services, is capable of conducting rapid high-efficiency global land surveys.
It can realise millimeter-level deformation monitoring to identify land subsidence, surface collapses and landslides, meaning it is an effective weapon for the early detection of major geological disasters.