In a collaborative project, NASA and the Indian Space Research Organisation (ISRO) have reached a significant milestone with the successful operation of their Earth observation satellite.
Equipped with advanced radar sensors, the mission strengthens global capabilities in monitoring Earth’s surface dynamics with unprecedented precision.
The satellite is designed to provide high-resolution radar imagery for a wide range of applications, including disaster management, climate monitoring, agricultural planning, and resource exploration.
The successful capture of these first images from NISAR is a remarkable example of how partnership and collaboration between two nations, on opposite sides of the world, can achieve great things together for the benefit of all.
Amit Kshatriya, NASA Associate Administrator
Expanding Remote Sensing
Traditional optical satellites are limited by cloud cover and darkness, which prevent continuous observation. To overcome these restrictions, the new satellite employs Synthetic Aperture Radar (SAR), a technology capable of imaging Earth’s surface under any weather conditions and at any time of day.
This project combines NASA’s expertise in microwave remote sensing with ISRO’s engineering and operational strengths, resulting in a radar system that delivers superior image resolution and data reliability.
Building on previous radar missions, the system incorporates advanced algorithms and faster data processing for improved precision and timeliness.
Inside the Technology: How the SAR System Works
The satellite is built around a state-of-the-art SAR instrument designed to capture fine surface details across various scales. Operating within a specific microwave frequency band, the radar system optimizes surface penetration and scattering sensitivity across different landscapes.
The antenna array, known for its phase stability and beam steering capability, enables flexible imaging from multiple angles and resolutions. The system reconstructs detailed surface maps through aperture synthesis and Doppler processing using coherent radar pulses that preserve phase information.
The L-band radar system can achieve resolutions as small as 15 feet (or five meters), allowing a clear distinction between urban infrastructure, vegetation patterns, and hydrological features.
Its dual and quad-polarization modes enable subtle differentiation of surface types, while the system’s multiple operating modes, Stripmap, ScanSAR, and Spotlight, balance wide-area mapping, detailed observation, and rapid response imaging.
Onboard data storage and processing units efficiently manage the large volume of radar information before transmitting it to ground stations for analysis and global data distribution.
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Early Results are Clear, Detailed, and Reliable
The first radar images transmitted by the satellite reveal exceptional clarity and surface detail. Unlike conventional optical sensors, the radar operates effectively under cloudy, rainy, or nighttime conditions, consistently capturing fine distinctions between urban areas, vegetation, and geological formations.
Early data analysis indicates the NASA-ISRO satellite has strong potential for use in flood mapping, deforestation monitoring, and soil moisture assessment.
With its ability to revisit the same region frequently and capture multi-angle data, the satellite is particularly valuable for tracking changes over time, which could include seasonal vegetation shifts or post-disaster recovery.
Researchers from both agencies are already exploring enhancements to further increase spectral range and resolution, enabling future applications in mineral exploration, glacier monitoring, and coastal change analysis.
As the mission continues, data from this satellite will be invaluable in ongoing climate studies, for guiding policy development, and supporting sustainable management of natural resources.