ISRO-NASA to Launch Earth Observation Satellite NISAR

ISRO-NASA to Launch Earth Observation Satellite NISAR

Why in News ISRO-NASA to Launch Earth Observation Satellite NISAR? 

Recently, ISRO and NASA announced the launch of their joint satellite mission called “NISAR”. This Earth observation satellite will lift off in July 2025. The mission reflects growing space cooperation between India and the United States. 

What is the Earth Observation Satellite “NISAR”?

• About: NISAR stands for NASA-ISRO Synthetic Aperture Radar. The satellite observes Earth using dual-frequency radar to study changes in land and ice. This collaboration represents the largest Earth observation satellite mission ever developed by the U.S. and India together.

• • • The total cost of the project is estimated to be around USD 1.5 billion, making it one of the most expensive Earth imaging satellite missions ever. 
    • NASA and ISRO jointly started the NISAR mission in 2014 under a formal agreement.

• Launch Details: The NISAR satellite is scheduled for launch on July 30, 2025, from the Satish Dhawan Space Centre (SDSC) in Sriharikota, Andhra Pradesh. The launch will be carried out using ISRO’s GSLV-F16 rocket. The vehicle will have a 4-meter fairing to accommodate the satellite’s large radar reflector.

• Timeline: Development of the NISAR satellite started in the mid-2010s. The radar systems were integrated in early 2024. In October 2024, NASA transported the radar payload from the Wallops Flight Facility in Virginia to India. The planned operational life of NISAR is three years, but it may be extended based on performance and data requirements.

• Objectives: The NISAR mission is designed to serve multiple scientific and practical purposes. Some of the main objectives include:

• • • Tracking earthquakes and landslides by detecting subtle ground movements.
    • Monitoring glaciers and ice sheets to understand climate-driven changes.
    • Observing soil moisture and agriculture cycles to support food security.
    • Mapping forest biomass and land use changes for environmental conservation.
    • Responding to disasters by providing rapid data after events like tsunamis or volcanic eruptions.

• Features: 

• • NISAR has a dual-frequency radar system that includes both L-band and S-band radars.
  • NASA provides the L-band radar, which works at a 24 cm wavelength and penetrates deeper into surfaces like ice, vegetation, and soil.
  • ISRO contributes the S-band radar, which operates at a 12 cm wavelength and captures surface-level details.
  • The satellite carries a 12-meter wide mesh antenna, which helps collect radar data with high resolution. Astro Aerospace developed the radar reflector, which is a key part of NISAR’s scanning technology.
  • It uses Synthetic Aperture Radar (SAR) to capture high-resolution images from space, even through cloud cover or darkness.
  • The satellite will operate on ISRO’s I-3K Bus Platform, which manages its radar instruments and all onboard systems.
  • The spacecraft generates 6,500 watts of power, which supports radar operations and data systems.
  • NISAR uses GPS receivers, which help determine its exact position while orbiting Earth.
  • A high-speed data recorder is onboard, which stores large volumes of data before transmission to ground stations.
  • The satellite uses a three-axis stabilization system, which keeps it oriented correctly for scanning.
  • It will orbit in a Sun-synchronous path, helping it observe Earth under the same lighting every cycle.
  • NISAR scans Earth every 12 days, covering land and ice masses multiple times a month.
  • The radar will observe land and ice areas 4 to 6 times each month with resolution ranging from 5 to 10 meters.
  • Data from the satellite will be open to all, supporting disaster relief and climate research.
  • The satellite uses thermal shielding, added after testing in 2024, to protect it from overheating during launch.

Also Read: GSLV-F15

What Are Earth Observation Satellites and How Do They Work?

• • Earth observation satellites are special types of satellites that orbit the Earth and collect information about its surface, atmosphere, and oceans. 
  • These satellites use advanced sensors to take pictures, measure temperatures, observe cloud patterns, and track environmental changes. 
  • Governments and scientists use this data to study weather, forests, agriculture, urban growth, natural disasters, and climate change.
  • These satellites carry cameras and sensors that can detect light, heat, or radio waves. Some sensors work in the visible light spectrum like human eyes. 
  • Earth observation satellites can monitor the same location regularly and detect even small changes over time.
  • There are two common types of orbits for Earth observation satellites. The first is geostationary orbit, where the satellite stays above the same point on Earth. These are used mainly for weather forecasting. 
  • The second is Sun-synchronous orbit, where the satellite moves around the Earth in such a way that it passes over the same location at the same local time.

• Mechanism: Earth observation satellites work through a series of steps that involve capturing, processing, and transmitting data about the Earth’s surface and atmosphere.

• • Earth observation satellites are placed into specific orbits to ensure they cover large parts of the planet.
  • Then these satellites start to collect data from various sensors: Optical sensors take high-resolution images of the land and oceans. Infrared sensors detect heat patterns, helping in forest fire or volcanic activity monitoring. Radar technology captures clear images during nighttime and through cloudy skies.
  • Once the data is captured, the satellite uses onboard computers to process it. 
  • When the satellite passes over designated ground stations, it sends the data back to Earth using high-speed communication systems. 

Also Read: Axiom Mission 4 

Benefits of Earth Observation Technology

• Disaster Management: It supports disaster response and risk management. Earth observation satellites help rescue teams during floods, earthquakes, and cyclones. They capture real-time images of affected areas and send data to ground stations within hours. For example, during the 2015 Nepal earthquake, satellite data helped locate damaged regions and guided rescue efforts. 

• Climate Change: It helps monitor climate change and the environment. Satellites track changes in ice sheets, sea levels, and global temperatures. They collect long-term data that shows how the climate is shifting over time. According to the IPCC 2021 report, Earth observation satellites have provided key evidence of melting glaciers and rising ocean temperatures. 

• Food Security: It improves agricultural planning and food security. This can monitor rainfall levels, measure soil moisture, and assess crop conditions. This helps improve crop yields and reduce losses. The FASAL project by ISRO in India uses Earth observation to predict crop output and guide farming decisions. This information reaches farmers through mobile apps or local offices.

• Urban Planning: It guides smart city development and urban planning. The satellite helps identify expanding cities, track road systems, and analyze land usage patterns. This helps design cleaner, safer, and better-connected cities. In fast-growing countries like India, Earth observation supports smart city missions by tracking population density, pollution, and green space. 

Also Read: SPADEX

India’s Earth Observation Satellites

• ISRO started Earth observation with the IRS-1A satellite, which it launched in 1988.
• India took its first step in Earth monitoring through the Indian Remote Sensing (IRS) program.
• IRS-1C and IRS-1D were two major satellites launched in the 1990s to support this initiative.
• Since then, India has launched more than 50 Earth observation satellites, making it one of the leading countries in remote sensing technology.
• The Cartosat satellites are known for their high-resolution imaging. 
• CARTOSAT-1, launched in 2005, was India’s first satellite with stereoscopic cameras for 3D mapping.
• The CARTOSAT-2 series (2, 2A, and 2B) launched between 2007 and 2010 offer high-resolution imaging up to sub-meter level. 
• The Radar Imaging Satellite (RISAT) series uses radar to observe Earth. These can capture images during night and through clouds. 
• RISAT-1, launched in 2012, and RISAT-2B, launched in 2019, have been useful during floods and cyclones. 
• Oceansat satellites observe oceans, wind patterns, and sea temperatures. Oceansat-2, launched in 2009, helped track cyclones and ocean productivity. 
• Megha-Tropiques is an atmospheric research satellite developed together by ISRO and CNES, France. It was launched in 2011 to study the tropical atmosphere, monsoon systems, and water vapor movement.
• SARAL, launched in 2013, is also an Indo-French mission focused on sea surface height measurement. It carries the ALTIKA altimeter, which provides accurate ocean topography data.
• India launched EOS-01 in 2020, which is an all-weather Earth observation satellite. It supports agriculture, forestry, and disaster monitoring.