GSLV-F16 makes history

 By R Anil Kumar

• ISRO and NASA have successfully launched the NISAR satellite from Sriharikota, marking a significant Earth observation mission. The $1.5 billion collaboration utilized the GSLV-F16 rocket, making it the first GSLV launch into a Sun Synchronous Polar Orbit

• With the successful liftoff of GSLV-F16, India further cements its growing role in international space partnerships. As scientists and engineers celebrate the launch, the world looks forward to the valuable stream of data NISAR promises to deliver

• ‘The most sophisticated radar we’ve ever built’: US-Indian NISAR satellite launches to track tiny changes on Earth’s surface: ISRO

• NISAR will be able to monitor “changes as small as a centimeter in any weather, and in both darkness and light”

The Indian Space Research Organisation (ISRO), in partnership with the US Space Agency National Aeronautics and Space Administration (NASA), has successfully launched the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite, a cutting-edge Earth observation mission, from Sriharikotathis evening 5.40 pm, IST: ISRO

Sriharikota: The Indian Space Research Organisation (ISRO), in partnership with NASA, has successfully launched the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite, a cutting-edge Earth observation mission, from Sriharikota on Wednesday, July 30.

Notably, the lift-off took place on July 30, 2025, at 17:40 IST from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

This landmark mission, over a decade in the making, represents a combined investment of more than $1.5 billion by the Indian and American space agencies.

NISAR was deployed into orbit aboard the GSLV-F16 (Geosynchronous Satellite Launch Vehicle). While such missions are typically carried out using the PSLV, this marks the first occasion a GSLV rocket has placed a satellite into a Sun Synchronous Polar Orbit.

It is noteworthy that the NISAR is the first radar imaging satellite globally to operate with dual radar frequencies, NASA’s L-band and ISRO’s S-band, enabling it to detect subtle shifts on the Earth’s surface, down to changes as small as a centimetre, according to the two space agencies.

“Liftoff! And we have liftoff! GSLV-F16 has successfully launched carrying NISAR,” ISRO announced on X.

Weighing 2,392 kilograms, the NISAR satellite has been successfully inserted into a sun-synchronous orbit. It will circle the Earth approximately every 97 minutes, capturing detailed images of land, ice, and select ocean surfaces every 12 days.

Designed with a mission lifespan of five years, NISAR is equipped to deliver vital data on changes to the Earth’s surface with exceptional accuracy.

Earlier in the day, ISRO had posted on X: “Launch Day has arrived for GSLV-F16 & NISAR. GSLV-F16 is standing tall on the pad. NISAR is ready. Liftoff today.”

Union Minister Jitendra Singh hailed the launch, calling it more than a satellite, it represents NISAR’s most distinctive feature is its dual-band Synthetic Aperture Radar, which utilises an innovative SweepSAR technology.

This allows the satellite to produce high-resolution images over broad geographic swaths.

ISRO noted that the satellite will map global land masses, ice-covered terrain, sea ice, islands, and select ocean regions every 12 days, using both L-band (from NASA) and S-band (developed by ISRO) radars.

The primary goals of the mission include monitoring land and ice deformation, analysing ecosystems, and observing oceanic phenomena of mutual interest to scientists in India and the United States.

The initial 90 days post-launch will be dedicated to the In-Orbit Checkout (IOC) phase, during which the satellite’s systems will be tested and calibrated before full scientific operations begin.

A notable aspect of the mission is its open data policy, all observations made by NISAR will be freely available to the global scientific community within one to two days, with near real-time access provided during emergency situations.

This mission also marks a milestone in microwave imaging, offering fully polarimetric and interferometric capabilities using two separate radar frequencies, an unprecedented feature in Earth observation satellites.

More about NISAR Mission

NISAR (short for NASA-ISRO Synthetic Aperture Radar) rose off the pad today at 8:10 a.m. EDT (1210 GMT; 5:40 p.m. India Standard Time) atop a GSLV Mk II, one of India’s brawniest rockets.

The three-stage, 170-foot-tall (52-meter-tall) launcher (whose name is short for Geosynchronous Satellite Launch Vehicle Mark II) did its job, deploying NISAR into a 463-mile-high (745-kilometer-high) orbit about 18.5 minutes after liftoff as planned.

“I am extremely happy to announce that GSLV Mk II vehicle has successfully and precisely injected the NASA ISRO Synthetic Aperture Radar satellite, NISR satellite, bringing 2300 kg into its intended orbit,” ISRO Chairman Dr V. Narayanan said to mission operators and guests in attendance at the launch after confirmation of payload separation. “Let me congratulate all the teams from ISRO and NASA JPL on this outstanding success.”

Following his remarks, NASA Deputy Associate Administrator Casey Swails said, “on behalf of NASA, I just I want to congratulate all of the teams. It is been just an incredible decade, culminating in this moment, from the technical collaborations, the cultural understandings, getting to know each other, building that team across continents, across time zones.”

“This Earth science mission is one of a kind, and really shows the world what our two nations can do. But more so than that, it really is a pathfinder for the relationship building that we see across our two nations,” she said.

Mission team members will spend the next 90 days or so checking out NISAR and its various systems, making sure everything is working well. Then, the satellite will begin its ambitious Earth-observing mission.

NISAR will scrutinize our planet’s surface using synthetic aperture radar (SAR), which can peer through clouds and operate in all lighting conditions. The spacecraft sports two SAR instruments, one built by NASA and the other by ISRO. Their radar signals will be beamed down to Earth by a 39-foot-wide (12-meter-wide), NASA-built antenna reflector, which launched in a folded configuration. The gold-plated mesh reflector will also catch the returning waves, which will hold lots of interesting information about the surface that bounced them back.

“With NISAR, we will see the precursors to natural hazards, such as earthquakes, landslides and volcanoes,” St. Germain said during Monday’s briefing.

“We’ll see land subsidence and swelling, movement, deformation and melting of mountain glaciers and ice sheets covering both Greenland and Antarctica, and, of course, we’ll see wildfires,” she added. “We’ll also see human-induced land changes, such as farm and ranch production, use of water for municipal drinking and farm irrigation and infrastructure, land development, houses, commercial buildings, railroads, highways and bridges.”

NISAR’s orbit takes it over both poles, so the satellite will get a good look at Earth’s ice sheets. NISAR will scan almost all of the planet’s ice- and land-covered area every six days, and it will do this work for at least five years. (The NASA SAR instrument has a three-year baseline mission life, but its ISRO counterpart is supposed to operate for five).

The total cost of the NISAR mission is about $1.5 billion. NASA is footing about 80% of that bill.

NISAR’s roots go all the way back to 2007; the mission was a response to the Earth-observation priorities laid out that year in a “decadal survey” published by the US National Academy of Sciences. The NISAR partnership was officially forged on Sept. 30, 2014, with the signing of documents by then-NASA Administrator Charles Bolden and then-ISRO Chairman K. Radhakrishnan.