China’s Gaofen-4 spacecraft is prepared for 2015 launch.
Credit: CAST

China has used a geostationary satellite – viewed by some as a powerful spy satellite of Earth – to make seamless maps of major elements of the Moon.

In a paper appearing in Research in Astronomy and Astrophysics, a team of space scientists and Earth observational researchers made use of the Gaofen-4 spacecraft to help understand the origin and evolution of the Moon.

Whole lunar disk

Maps of major elements using the single-exposure image of the whole lunar disk were obtained by China’s high-resolution geostationary satellite.

A spatial resolution of roughly 500-meters was achieved.

“The elemental contents of soil samples returned by Apollo and Luna missions are regarded as ground truth, and are correlated with the reflectance of the sampling sites extracted from Gaofen-4 data,” the paper states.

The Gaofen-4 data products allowed major elements for the Moon’s maria and highlands to be estimated and compared.

Copernicus crater imaged by China’s high-resolution geostationary satellite, Gaofen-4, at four different local times.
Credit: Y. Lu et al.

Powerful telescope

According to the popular satellite tracking website, N2YO.com, Gaofen-4 is outfitted with a powerful telescope to collect nearly continuous imagery of the Asia-Pacific, a capability that could help track foreign naval activity.

“Gaofen 4’s staring imager can spot objects as small as 50 meters (164 feet), a resolution that allows the satellite to see an oil tanker steaming across the ocean. At night, an infrared camera aboard Gaofen 4 can capture less detailed imagery with a resolution of about 400 meters, or 1,300 feet. Gaofen 4 is designed for an eight-year lifetime,” the N2YO.com notes.

Gaofen-4 was launched in December 2015 on a CZ-3B/G2 rocket from China’s Xichang space center.

The spacecraft has also been tagged as supporting disaster response, forestry, earthquake and meteorology applications, and supplements an advanced technology for natural disaster alerts, be they for wild fires, typhoon, along with national security duties.

To view the paper – “Seamless maps of major elements of the Moon: Results from high-resolution geostationary satellite” – go to:

https://iopscience.iop.org/article/10.1088/1674-4527/21/2/31

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