China’s Tianwen-1 mission, which successfully entered Mars’ orbit in July 2020, has now accomplished a significant milestone by releasing the first high-resolution global color-image map of Mars. This new map, with a spatial resolution greater than 1 kilometer, represents the highest resolution achieved so far, potentially aiding future crewed missions to the Red Planet.
The newly created map stands in contrast to previous global maps produced by missions like Mariner 9, Viking 1 and 2, Mars Global Surveyor, Mars Reconnaissance Orbiter, Mars Express, and Mars Odyssey. While these missions provided crucial data, their maps had lower spatial resolutions. For instance, the Mars Global Surveyor’s MOC-WA Atlas Mosaic had a resolution of 232 meters per pixel in the visible band, whereas the Mars Odyssey’s THEMIS Global Mosaic offered approximately 100 meters per pixel in infrared.
Advanced Imaging Techniques
Led by Professor Li Chunlai from the National Astronomical Observatories of China and Professor Zhang Rongqiao from the Lunar Exploration and Space Engineering Center, the research team utilized images captured by the Tianwen-1 orbiter’s optical camera and imaging spectrometer. A total of 14,757 images were taken over more than 284 orbits, achieving spatial resolutions between 57 and 197 meters. The Mars Mineralogical Spectrometer also contributed by acquiring 325 strips of data in visible and near-infrared bands, with resolutions varying from 265 to 800 meters.
Seamless Integration
By treating Mars as a unified adjustment network, the researchers reduced positional deviations between images to less than one pixel, enabling the creation of a seamless global mosaic. The mission’s Mars Mineralogical Spectrometer provided the true colors of the Martian surface, and additional color correction ensured uniformity across the entire map. This resulted in the “Tianwen-1 Mars Global Color Orthomosaic 76 m v1,” featuring a spatial resolution of 76 meters and a horizontal accuracy of 68 meters.
“Creating this map required meticulous efforts in data processing and optimization,” stated Professor Li Chunlai.
“This map will serve as a crucial geographic reference for future Mars missions,” added Professor Zhang Rongqiao.
The Tianwen-1 map offers unprecedented resolution and color fidelity, surpassing previous global Mars maps. This enhanced map will significantly aid space agencies in selecting exploration sites for future robotic missions and potential crewed missions, which could commence by the 2030s or 2040s. It also stands as an essential tool for ongoing scientific investigations into Mars’ geological and atmospheric conditions.
