NISAR stands for NASA-ISRO Synthetic Aperture Radar. It’s a collaborative effort between NASA and the Indian Space Research Organization (ISRO). Both agencies are contributing radars optimized for different purposes, allowing the mission to observe a wide range of changes on Earth’s surface. NISAR can detect movements as small as 0.4 inches over areas roughly the size of a tennis court.

About NISAR

• NISAR is an SUV-sized satellite jointly developed by NASA and ISRO.
• The partnership agreement was signed in September 2014, with NASA providing one radar, communication subsystem, GPS receivers, and payload data subsystem, while ISRO provides the spacecraft bus, S-band radar, launch vehicle, and associated services.
• The satellite is scheduled for launch in 2022 from Sriharikota, India, into a near-polar orbit.
• It will scan the globe every 12 days during its three-year mission, providing unprecedented views of Earth’s land, ice sheets, and sea ice.
• NISAR’s goal is to make global measurements of land surface changes using advanced radar imaging.
• The mission concept and partnership are in response to the National Academy of Science’s 2007 survey of Earth observational priorities.
• Top priorities identified in the survey include gaining data and insight into ecosystems, deformation of Earth’s crust, and cryospheric sciences.

Mission Characteristics

What is a Synthetic Aperture Radar

• Synthetic-aperture radar (SAR) is a type of radar that generates two-dimensional images or three-dimensional reconstructions of objects, such as landscapes.
• SAR achieves higher spatial resolution than conventional radars by moving its antenna over a target region.
• Typically mounted on moving platforms like aircraft or spacecraft, SAR originated as an advanced form of side-looking airborne radar (SLAR).
• SAR’s resolution relies on the size of its synthetic antenna aperture, determined by the distance it travels over a target during illumination. Objects farther away stay illuminated longer, resulting in consistent spatial resolution across viewing distances.
• SAR images are created by transmitting radio wave pulses to “illuminate” a scene, receiving and recording the echoes with a single beam-forming antenna. The antenna’s location changes as the carrying aircraft or spacecraft moves, capturing multiple perspectives of the scene.

Applications of NISAR

• NISAR, a joint U.S. and Indian mission in collaboration with ISRO, focuses on studying hazards and global environmental changes.
• Its primary goal is to measure Earth’s surface changes, including natural processes and human activities, to enhance our understanding of natural hazards.
• NISAR will provide valuable data on biomass, natural hazards, sea level rise, groundwater, and other environmental factors.
• With its 12-day regularity in observing Earth’s land and ice-covered surfaces, NISAR aims to provide comprehensive global coverage every six days over a three-year baseline mission.
• The mission’s data will support various applications, including resource management, disaster response, and climate change research.
• NISAR’s rapid coverage will enable quick response to disasters by providing data for assessing damage and guiding ground inspections.
• Its mapping capabilities will aid in estimating initial damage and assessing the impact of disasters with high precision.

Significance from the point of India-US relations

• India and the United States, both major space players, are teaming up on Space Situational Awareness (SSA) to ensure safe and sustainable space operations.
• SSA collaboration is crucial due to their heavy reliance on space assets for various functions.
• Sharing SSA data is vital, given their significant investments in space. They’re also partnering on Satellite Navigation (SatNav) for disaster preparedness and natural resource management worldwide.
• This collaboration extends to weather systems and applications, benefiting both countries and beyond.

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