“On September 6, 2023, the Indian Space Research Organisation (ISRO) announced that the Chandrayaan-3 lander had been photographed by the Dual-frequency Synthetic Aperture Radar (DFSAR) instrument mounted on the Chandrayaan-2 Orbiter.
Chandrayaan-3 Captured by Chandrayaan-2: Image of the Chandrayaan-3 Lander taken by the Dual-frequency Synthetic Aperture Radar (DFSAR) instrument onboard the Chandrayaan-2 Orbiter. (Image: X/@isro) Chandrayaan-3 Lander Spotted by Chandrayaan-2: The DFSAR instrument aboard the Chandrayaan-2 Orbiter captured images of the Chandrayaan-3 lander on September 6, 2023. This significant achievement by ISRO occurred just days before the Chandrayaan-3 lander’s anticipated soft landing in August.
ISRO reported, “Chandrayaan-3 lander is imaged by the Dual-frequency Synthetic Aperture Radar (DFSAR) instrument onboard the Chandrayaan-2 Orbiter on September 6, 2023.”
In another notable development, a NASA satellite known as the Lunar Reconnaissance Orbiter (LRO) also recently photographed the Chandrayaan-3 landing site.
Understanding the SAR Instrument
The Synthetic Aperture Radar (SAR) instrument functions by transmitting microwaves within specific frequency bands and receiving the corresponding signals scattered from the surface. Notably, SAR can produce images even without relying on solar illumination, making it ideal for remote sensing purposes. It offers precise measurements of both distance and physical characteristics of target features. Therefore, SAR technology is widely employed for remote sensing applications, including the exploration of Earth and other celestial bodies.
DFSAR: A Key Scientific Instrument
DFSAR, a pivotal scientific instrument aboard the Chandrayaan-2 Orbiter, operates within the L- and S-band frequency bands. It stands as a state-of-the-art device renowned for providing the highest-resolution polarimetric images among planetary missions. The extended radar wavelength enables DFSAR to delve deep into lunar subsurface features, capturing details down to a few meters. Over the past four years, DFSAR has consistently delivered valuable data by imaging the lunar surface, with a primary focus on advancing lunar polar science.