Seventeen days after its launch on July 30, 2025, from India’s Satish Dhawan Space Centre, the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite successfully deployed its giant radar antenna reflector in orbit on August 15, 2025.

This reflector is an essential piece of the satellite’s science hardware and measures an impressive 39 feet (12 meters) in diameter. It is the largest antenna reflector ever deployed for a NASA mission, reported NASA's Jet Propulsion Laboratory.

The reflector had initially been stowed in an umbrella-like configuration and was placed on a 30-foot (9-meter) boom that was first extended and locked into place. The deployment sequence began with the release of small explosive bolts that held the reflector in place.

This initiated a "bloom" process, where the reflector unfurled by releasing stored tension in its flexible frame. Motors and cables then pulled the reflector into its final locked position, a process that took about 37 minutes, during which the reflector expanded from about 2 feet across to its full 39-foot diameter.

The antenna comprises a cylindrical frame made of 123 composite struts covered with a gold-plated wire mesh and weighs approximately 142 pounds (64 kilograms). This reflector plays a critical role in directing microwave pulses from NISAR’s two synthetic aperture radar (SAR) systems—an L-band radar that can penetrate clouds and forest canopy and an S-band radar that is more sensitive to vegetation moisture and snow.

Together, these radars scan nearly all of Earth's land and ice surfaces twice every 12 days, producing high-resolution images down to about 30 feet (10 meters) across.

The deployment of this reflector is crucial since it simulates a radar antenna aperture that would otherwise have to be 12 miles (19 kilometers) long for the L-band radar’s resolution if using a traditional antenna.

By using SAR techniques, NISAR can achieve the sharpness of a camera’s lens, delivering detailed and timely data on ground deformation from earthquakes, volcanoes, and landslides, ice sheet and glacier motion, changes in forests and wetlands, and more.

After deployment, the team at NASA’s Jet Propulsion Laboratory, which manages the U.S. contribution to the NISAR mission, will fine-tune the radar systems to prepare for the satellite’s full science operations expected to begin later in 2025.

This technology and mission represent a significant advancement in Earth observation, enabling researchers and decision-makers worldwide to gain unprecedented insights into natural hazards, environmental changes, and infrastructure monitoring.

The August 15, 2025 deployment of NISAR’s 39-foot radar antenna reflector marks a major milestone that will enable the satellite’s dual-frequency radar system to deliver transformative scientific data with unprecedented coverage and detail for Earth’s changing surface. This feat of engineering and collaboration between NASA and ISRO advances our capacity to observe and understand our dynamic planet.

Jet Propulsion Laboratory Report