The historic NISAR mission, a landmark collaboration between NASA and ISRO, has entered its crucial 90-day commissioning phase, during which scientists will carry out rigorous checks, calibrations and orbital adjustments to prepare the satellite for full-scale earth observation.

The critical phase follows the successful launch of the radar imaging satellite on July 30 aboard a GSLV-F16 rocket from Srikharikota in Andhra Pradesh.

Speaking to PTI, Gerald W Bawden, Program Manager for Natural Hazards Research at NASA’s Earth Sciences Division, outlined the key activities underway.

“NISAR is inserted at an altitude of 737 km and we need to actually rise up to 747 km and it will take about 45-50 days for those operations to take place,” he explained.

After the commissioning is complete, he said the radars will be activated and it will start collecting data over “all ice, all land, all the time” from the Earth.

“The resolution will be 5 metres by 5 metres and we will be imaging that every 12 days. So it is a lot of data. It is more data that NASA has collected in any other mission.” On the key lessons from the collaboration with the Bengaluru-based space agency for the NISAR mission, the scientist said, NASA learned from the ISRO’s focus on how science can help society, while ISRO gained from NASA’s deep focus on scientific research.

Bawden said the project brought together scientists from two countries on opposite sides of the world, with a 12.5-hour time difference.

“… we had culture differences and the other thing is that we are on the opposite side of the world. We have to work together and we have the common love for technology.”

“The two scientists (of ISRO and NASA) are building partnerships by working together, friendships. This NISAR partnership is more than building an amazing satellite, it is teams that are together to solve bigger problems,” he noted.

Responding to a query on the opportunities the collaboration with ISRO offers for NASA, NASA Earth Sciences Division Program Executive Sanghamitra B Dutta said, “This is the first large earth observing misison that India and the United States have put together. India is also working on this human space flight. So there are collaborations between the US and India on this over the last 4-5 years.”

“An Indian astronaut (Subhanshu Shukla) recently went to the International Space Station that has also been built as part of a collaboration between the US and India. We are enormously proud to work with each other and it will come in future in the commercial area, space collaboration and technology development, science area,” she said.

Regarding the mission’s dual-band radar, Dutta said radar missions have happened in the past.

“But simultaneous observation (of the Earth) in two different frequencies by two different radars flying together did not happen before. Scientists need not confine to the boundary of a country and they always discuss possibilities of new missions and bigger and better science,” she said.

During discussions, Dutta said scientists from ISRO and NASA came up with the idea to fly two Radars at once, using two different frequencies to collect more data in different technical ways.

“The idea was first discussed between Space Applications Centre, ISRO Ahmedabad and scientists from Jet Propulsion Laboratory, NASA. They discussed, brainstormed and came up with the idea of two radars working simultaneously.” Supporting Dutta’s statement, Bawden said there are major benefits of having two frequencies.

“We have technology challenge, and at the end of the day, we are building the technology to address scientific questions and NASA has the long L Band while ISRO has S band. It is fantastic to study agriculture like how corn grows, soya beans grow.”

The NISAR mission, a collaborative effort between ISRO and NASA, will demonstrate Indian space engineering capabilities for Earth observation on a global scale, a top scientist has said.

The NISAR (NASA-ISRO Synthetic Aperture Radar) is a global mission, and its data will be accessible for download worldwide by users, said Radha Krishna Kavuluru, former Ground Segment Engineer and Ex-Project Manager of NISAR.

ISRO is set to launch the NISAR satellite aboard the GSLV-Mk II rocket from Sriharikota, Andhra Pradesh, on July 30 at 5:40 p.m. The GSLV-F16 marks the 18th flight of India’s Geosynchronous Satellite Launch Vehicle and the 9th operational flight with an indigenous cryogenic stage.

The countdown is expected to commence later on Tuesday (July 29, 2025), ISRO sources said.

This mission is the first GSLV launch to achieve a Sun-Synchronous Polar Orbit. The 51.7-meter-tall, three-stage rocket will lift off from the second launch pad, approximately 135 km east of Chennai. About 19 minutes after launch, the satellite is expected to be placed into its designated orbit.

Explained | What are ISRO and NASA aiming to achieve with the NISAR satellite?

Elaborating on the mission, Mr. Kavuluru explained that NASA provides the L-Band, while ISRO contributes the S-Band for the Synthetic Aperture Radar, enabling the collection of vast amounts of data.

“The satellite will transmit extensive data covering the Earth, including Antarctica, the North Pole, and oceans,” he told PTI.

Highlighting the mission’s significance, Mr. Kavuluru noted that unlike earlier ISRO observation satellites such as the Resourcesat and RISAT series, which could capture images globally but were operationally focused on India and surrounding regions, NISAR will collect data across the entire globe for operational use.

“This data will be extensively utilised by governments and commercial entities worldwide,” he said.

“NISAR is one of the key missions that will garner large-scale operational user feedback from across the globe,” Mr. Kavuluru emphasised.

“All countries will leverage NISAR data for various applications, showcasing the strength of Indian space engineering. This is the core importance of the mission,” he added.

Mr. Kavuluru underscored the mission’s importance as ISRO’s first major partnership with NASA for an Earth observation satellite. “This collaboration fosters significant technical exchange, with ISRO and NASA sharing insights into their respective planning and execution processes,” he said.

Mr. Kavuluru added that ISRO will process and make most of the data available as open-source, accessible to users globally. The satellite, which will cover the entire Earth every 12 days, will provide approximately 2.5 coverages per month and 10 coverages in 120 days.

“This will enable us to monitor seasonal changes, including forest dynamics, mountain shifts, and glacier movements in regions like the Himalayas and Antarctica,” he explained.

“This is a highly significant, high-value, and ambitious mission for ISRO,” Mr. Kavuluru remarked. The GSLV-F16/NISAR mission is designed for a lifespan of five years.