First Radar Images from Joint NASA-ISRO Satellite Offer Unprecedented Views of Earth

The NISAR (NASA-ISRO Synthetic Aperture Radar) satellite, a collaborative effort between NASA and the Indian Space Research Organisation (ISRO), has transmitted its initial radar images of Earth’s surface, providing a preview of the mission’s scientific capabilities as it nears full operational status. These images showcase the satellite’s ability to capture highly detailed information about land cover and surface changes, which will be crucial for applications ranging from disaster response to agricultural monitoring.

The NISAR satellite, launched by ISRO on July 30, is equipped with advanced radar systems designed to observe Earth’s land and ice surfaces. The mission’s L-band synthetic aperture radar (SAR) system, developed by NASA’s Jet Propulsion Laboratory, has demonstrated its capacity to resolve objects as small as 15 feet (5 meters). An image captured on August 21 of Mount Desert Island in Maine illustrates this detail, differentiating between water bodies, forested areas, and built-up regions like the town of Bar Harbor. The L-band radar utilizes a 10-inch (25-centimeter) wavelength, allowing it to penetrate forest canopies and measure soil moisture, as well as detect subtle movements of ice surfaces and land formations. This capability is essential for understanding processes leading up to and following natural events such as earthquakes, volcanic eruptions, and landslides.

Further showcasing the satellite’s versatile imaging abilities, data collected on August 23 over northeastern North Dakota revealed detailed information about the landscape along the Forest River. This imagery distinguished between forests and wetlands bordering the river, and agricultural lands to the north and south. Different shades in the agricultural plots indicated fallow fields, as well as areas likely used for crops like soybeans and corn, with circular patterns suggesting the use of center-pivot irrigation. The NISAR mission also incorporates an S-band radar system, provided by ISRO, which uses a 4-inch (10-centimeter) microwave signal. This system is particularly effective at monitoring smaller vegetation, making it suitable for studying grassland ecosystems and certain types of agriculture.

The NISAR satellite is unique in carrying both L- and S-band radars, allowing for comprehensive Earth observation. It is designed to monitor Earth’s land and ice surfaces with a revisit time of twice every 12 days. The spacecraft is equipped with a large, 39-foot (12-meter) wide antenna reflector, the largest NASA has ever deployed in space, to facilitate its extensive data collection. The mission represents a significant international partnership, building on a history of cooperation in space exploration between the United States and India. Various components of the NISAR mission, including the spacecraft bus, launch vehicle, and launch services, were provided by Indian entities, while NASA’s Jet Propulsion Laboratory manages the U.S. component, including the L-band SAR and associated subsystems. Data from the L-band radar is received by NASA’s Near Space Network. The mission is expected to commence its full science phase in November, following the satellite’s recent elevation to its operational orbit.

Article by Mel Anara, based upon information from NASA News

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