NISAR, short for NASA-ISRO Synthetic Aperture Radar, is one of the most ambitious Earth observation satellite missions ever undertaken. It is a joint collaboration between NASA (USA) and ISRO (India), and it aims to monitor changes in Earth’s surface with unmatched accuracy.
Launched aboard a GSLV rocket, NISAR will provide crucial data on climate change, natural disasters, glaciers, agriculture, and much more. It carries two powerful radar systems – L-band (NASA) and S-band (ISRO) – capable of penetrating through vegetation, clouds, and even the Earth’s surface to detect minute shifts.
🏗️ How Was NISAR Built?
The making of NISAR was a multi-year global collaboration, combining the best of American engineering with Indian aerospace capability:
NASA developed the L-band radar, the deployable 12-meter radar antenna reflector, and other subsystems including high-rate data recording systems.
ISRO contributed the satellite’s bus system, S-band radar, launch services, and mission operations control.
Key milestones:
Design Phase: Engineers worked across continents to integrate radar payloads capable of high-resolution imaging from orbit.
Assembly: Components were shipped between Jet Propulsion Laboratory (USA) and U R Rao Satellite Centre (India).
Testing: The satellite underwent extreme thermal, vibration, and vacuum tests to simulate launch and space conditions.
Launch Readiness: Integrated at the Sriharikota launch site and successfully launched aboard GSLV Mk II.
⏳ Why the 90-Day Wait?
Despite being launched successfully, NISAR won’t start delivering usable data immediately. Here’s why it takes up to 90 days:
1. Orbit Stabilization
After launch, the satellite must reach and stabilize in its precise Sun-synchronous polar orbit (747 km altitude). Small corrections take time to ensure the correct path.
2. Antenna Deployment
The radar reflector, a massive 39-foot (12-meter) boom, must be carefully unfolded in space. This complex mechanism needs meticulous, gradual deployment followed by calibration.
3. System Calibration
Both the L-band and S-band radar systems need rigorous cross-checking. Engineers must fine-tune:
Antenna pointing accuracy
Data link performance
Instrument response
Sensor synchronization
4. Ground Data Systems Testing
ISRO and NASA ground stations must verify that data transmission, storage, and processing systems are working correctly — crucial before making data publicly available.
5. Commissioning Phase
In this phase, performance metrics are validated. Minor hardware or software issues can emerge during real-time space operation that need debugging.
🌍 What Will NISAR Monitor?
Once operational, NISAR will scan nearly the entire globe every 12 days and provide highly detailed data. Its goals include:
Measuring glacier movements and sea level rise
Monitoring agricultural productivity
Tracking earthquakes, volcanoes, and landslides
Detecting forest degradation and wetlands
Supporting climate change models with real-time data
🔍 Why NISAR Data Is a Game-Changer
Most Earth observation satellites can either see through clouds (radar) or detect optical details (camera/infrared) — not both. NISAR uses interferometric SAR technology, allowing:
24/7, all-weather surface imaging
Millimeter-scale deformation detection
Continuous mapping of areas prone to natural disasters
📅 When Will the First Public Data Be Available?
If commissioning and calibration go as planned, early usable data from NISAR may be available by late 2025, with open-access archives for scientists and researchers worldwide.
🔗 Final Thoughts
The NISAR mission isn’t just a technological marvel—it’s a symbol of global cooperation in the face of climate challenges. The 90-day delay may seem long, but it’s essential to ensure the satellite’s data will be accurate, stable, and useful for years to come.
