NISAR milestone: Antenna reflector successfully deployed

New Delhi: Seventeen days after the launch of the Nasa-Isro Synthetic Aperture Radar (NISAR) satellite, a key milestone was reached when the onboard 12-m drum-shaped antenna reflector, weighing 64 kg, was successfully deployed, setting the stage for the start of data collection.

The reflector had been stowed, umbrella-like, until the 9-m boom that supports it could be deployed and locked in place, said Nasa's Jet Propulsion Laboratory in a statement.

“The successful deployment of NISAR’s reflector marks a significant milestone in the capabilities of the satellite,” said Karen St Germain, director of the Earth Science Division at Nasa Headquarters in Washington. In the next step, the two radars will be calibrated before actual data-gathering starts.

The satellite — launched on July 30 from Sriharikota using Isro’s Geosynchronous Satellite Launch Vehicle — will bounce microwave signals off Earth’s surface and receive the return signals on the giant radar antenna reflector.

Its ability to see through clouds and rain — day and night — is expected to enable users to continuously monitor earthquake and landslide-prone areas and determine, among other things, how quickly glaciers and ice sheets are changing.

It will also keep a constant watch on the deformation of land due to earthquakes, volcanoes, and landslides, and changes in forest and wetland ecosystems down to fractions of an inch. It will also aid decision-makers in fields as diverse as disaster response, infrastructure monitoring, and agriculture.

The mission reportedly carries the most sophisticated radar systems ever launched. It combines two synthetic aperture radar systems: a Nasa-made L-band system that can see through clouds and forest canopy, and an Isro-made S-band system that can see through clouds as well but is more sensitive to light vegetation and moisture in snow.

The reflector plays a key role for both systems, which was why the successful deployment of the hardware was such a significant milestone.