Wednesday (July 30) marks a historic moment for India’s space programme as the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite prepares for launch from Sriharikota. This groundbreaking mission represents not just a technological achievement but a bold step toward understanding our changing planet in unprecedented detail. NISAR will lift off on July 30, 2025, at 5.40 pm IST aboard ISRO’s GSLV-F16 rocket, marking the culmination of years of Indo-American space cooperation.
The rocket journey to orbit will take approximately 19 minutes, after which NISAR will be injected into its designated 747-kilometre Sun-synchronous orbit. What makes this mission extraordinary is not just its ambitious scope, but the patience and precision required to make it operational.
The journey to orbit and beyond
Once NISAR reaches its designated orbit at 747 kilometres above Earth, the real work begins. The satellite will undergo a critical 90-day commissioning phase, also known as “In-Orbit Checkout,” during which the observatory will be meticulously prepared for its scientific tasks. This means that while the launch is tomorrow, Indians will have to wait until late October before NISAR begins its full scientific operations.
“A key highlight of this commissioning phase is deploying NISAR’s massive 12-meter diameter reflector, one of the largest ever flown on an Earth observation satellite. This enormous antenna, roughly the size of a tennis court when fully deployed, must unfurl with extreme precision in the harsh environment of space. The deployment process is so critical that engineers have spent years perfecting every detail. The commissioning phase involves multiple stages. Initially, engineers will verify the health of the satellite’s basic systems, ensuring everything survived the violent launch process. Then comes the delicate task of deploying the giant reflector and its 9-meter boom, followed by extensive testing of both NASA’s L-band and ISRO’s S-band radar systems,” explained space analyst Girish Linganna.
A three-year mission with a global impact
Once operational, NISAR will observe Earth’s land and ice-covered surfaces globally with 12-day regularity, sampling Earth on average every 6 days for a baseline 3-year mission. This frequency of observation is revolutionary. Unlike optical satellites that can be hindered by clouds or darkness, NISAR’s radar systems work in all weather conditions, day and night.
Experts point out that the satellite’s capabilities are truly impressive. NISAR will map the elevation of Earth’s land and ice masses 4 to 6 times a month at resolutions of 5 to 10 metres.
To put this in perspective, the satellite can detect changes in the ground as small as a few centimetres, precise enough to monitor the gradual movement of tectonic plates or the melting of glaciers.
Real-world applications for India
For a country like India, which faces numerous natural challenges, NISAR’s data will prove invaluable. The satellite will monitor everything from monsoon- flooding to earthquake activity along the Himalayan fault lines. Data collected from NISAR will reveal information about the evolution and state of Earth’s crust, help scientists better understand our planet’s natural processes and changing climate, and aid future resource and hazard management.
Indian farmers will benefit from precise monitoring of crop conditions and soil moisture. Urban planners can track land subsidence in rapidly growing cities like Delhi and Mumbai. Disaster management agencies will receive crucial data about landslides in mountainous regions and coastal erosion along India’s extensive coastline.
A partnership model for the future
With a total cost of approximately $1.5 billion, NISAR represents one of the world’s most expensive Earth-imaging satellites. ISRO’s contribution is about ₹788 crore, while NASA’s share is about $1,118 million. This cost-sharing model demonstrates how international cooperation can achieve objectives that might be prohibitively expensive for any single nation.
The partnership extends beyond finances. NASA provides the L-band radar and sophisticated data processing systems, while ISRO contributes the S-band radar, satellite bus, and launch services. This division of responsibilities plays to each agency’s strengths and has created a template for future international space collaborations.
Challenges and lessons learned
“The road to launch hasn’t been smooth. Originally scheduled for March 2024, the mission faced delays when engineers discovered that the large radar reflector might overheat during launch. The satellite was shipped back to California for modifications, demonstrating the uncompromising attention to detail required for such complex missions. These delays, while frustrating, highlight the meticulous planning essential for space missions. There are no second chances in space, and the investment in getting everything right on Earth pays dividends once the satellite is operational,” Linganna told THE WEEK.
Looking ahead
All data from NISAR will be freely available one to two days after observation and within hours in case of emergencies like natural disasters. This open data policy ensures that the benefits reach not just government agencies but also researchers, NGOs, and local communities worldwide.
As NISAR prepares for launch, it represents more than just another satellite. It embodies India’s growing capabilities in space technology and its commitment to using space-based tools for sustainable development. The three-year mission will generate an unprecedented dataset about our changing planet, providing insights that will influence policy decisions for decades to come.
The July 30 launch is just the beginning. The real excitement will come in late October when NISAR opens its sophisticated eyes and begins its systematic watch over our dynamic Earth. For India, it marks another giant leap in its space journey, this time with a clear focus on understanding and protecting our home planet.
