November 08, 2025
The Chandrayaan-2 Orbiter is in orbit around the Moon since 2019 and has been providing high quality data. One of the payloads, the Dual Frequency Synthetic Aperture Radar (DFSAR) is the first instrument that has mapped the Moon using L-band in full-polarimetric mode and in highest resolution (25m/pixel). This advanced radar mode sends and receives signals in both vertical and horizontal directions, making it ideal for studying surface properties.
Since launch, about 1400 radar datasets were collected and processed to create polarimetric mosaics of north and south polar region (80 to 90 deg latitude) of the Moon. Using the datasets, the scientists from Space Applications Centre (SAC), Ahmedabad have developed advanced data products, on potential presence of water-ice, surface roughness, as well as an important electrical property, namely dielectric constant which describes features like density and porosity of the Moon’s surface. The algorithm for analysing the full-polarimetric data is developed and data products are generated indigenously by ISRO.
These advanced data products are significant in view of gathering a first-order information about Moon’s polar regions. Such regions are expected to have preserved the early chemical conditions of the solar system, which are important clues to explain several facets of evolution of the planetary bodies. This kind of ready-to-use data products on lunar polar regions has always been sought after, because it will provide holistic information to characterise the polar regions for future lunar exploration. These products complement hyperspectral data in studying the distribution of minerals on the Moon.
The polar mosaics include key radar parameters that reveal the physical and electrical (dielectric) characteristics of the Moon’s surface and subsurface.
The parameters include:
The derived Polar Mosaic products (Level 3C) are released for the users and freely available in Indian Space Science Data Centre (ISSDC) PRADAN website:
https://pradan.issdc.gov.in/ch2/protected/browse.xhtml?id=sar
The products can be visualized in CH2 MapBrowse:
https://chmapbrowse.issdc.gov.in/MapBrowse/
ISRO encourages the scientific community to explore these data products.
Figure: Radar Polarimetric Decomposition Maps of Lunar North (left) and South (right) Pole
Figure: (Left) Optical and (Right) DFSAR Image of Peary Crater region in Lunar North Pole, from a section marked on the mosaic