NASA and the Indian Space Research Organisation (ISRO) are set to launch the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite in March 2025.
This ₹5,000-crore joint mission aims to revolutionize Earth observation with cutting-edge technology and unparalleled precision.
The satellite, weighing 2.8 tonnes, will be launched aboard ISRO’s GSLV Mk-II rocket from the Satish Dhawan Space Centre (SDSC) in Sriharikota, India. NISAR will operate in a sun-synchronous orbit at an altitude of 747 km, with a planned mission duration of three years.
The Vision Behind NISAR
Conceived in 2009, the NISAR mission solidifies a decade-long partnership between NASA and ISRO.
Initially, NASA sought Germany’s involvement but later partnered with India following ISRO’s successful missions, including Chandrayaan-1 and RISAT-2. The mission formally began in 2014, emphasizing the mutual commitment of the two space agencies to scientific advancement.
NISAR’s primary objective is to monitor changes on Earth’s surface with unmatched accuracy. By scanning nearly all of Earth’s land and ice surfaces twice every 12 days, the satellite will capture intricate details about ecosystems, land dynamics, ice formations, and geological phenomena.
Advanced Technology Sets NISAR Apart
At the heart of NISAR is Synthetic Aperture Radar (SAR) technology, which enables the satellite to capture high-resolution images using radio signals. Unlike optical imaging satellites, SAR can operate in darkness, penetrate dense vegetation, and function in adverse weather conditions.
NISAR features dual-frequency radars- NASA’s L-band (1.25 GHz) and ISRO’s S-band (3.20 GHz) to achieve a balance between deep penetration and high-resolution imaging. It boasts a 240-km swath width, 10-meter resolution, and a 12-day revisit cycle, making it one of the most advanced Earth observation satellites ever built.
The satellite’s massive 12-meter drum-shaped reflector, contributed by NASA, transmits and receives microwave signals to and from Earth’s surface. This reflector underwent rigorous testing in California before being transported to Bengaluru, India, in October 2024 for integration with the spacecraft. Engineers applied reflective tape to manage temperature fluctuations, ensuring the reflector could deploy seamlessly during operations.
Transformative Applications of NISAR
NISAR’s capabilities are poised to transform several fields:
- Earth Observation: The satellite will monitor ecosystems, vegetation, and land use, offering valuable data for climate studies and biodiversity research.
- Geological Monitoring: It will track subtle surface changes, including movements caused by earthquakes, landslides, and volcanic activity, contributing to disaster prediction and response.
- Infrastructure Assessment: By detecting changes as small as an inch, NISAR can evaluate the stability of critical infrastructure like dams, bridges, and buildings.
- Climate Research: Observations of glaciers, ice sheets, and wetlands will provide insights into climate change and its impact on the planet.
The satellite is expected to generate a staggering 26 terabits of data daily. This data will be processed using a streamlined management system, ensuring timely delivery of critical information for scientific and practical applications.
Overcoming Challenges
The NISAR mission faced delays due to technical complexities, particularly with its radar antenna reflector. However, NASA and ISRO overcame these challenges, ensuring that the satellite is ready for its 2025 launch.
The reflector and other components were successfully reintegrated at ISRO’s Spacecraft Integration and Test Establishment (ISITE) in Bengaluru, marking a significant milestone in the mission’s progress.
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