The Indo-US Space cooperation has a chequered history. The most recent development in their bilateral space cooperation was the launch of the NISAR satellite on July 30, 2025. The word NISAR comes from the acronymising NASA-ISRO Synthetic Aperture Radar. It will use dual frequencies and thereby will become the first radar imaging satellite to do so. Due to the remote-sensing nature of this satellite, it is expected to monitor (observe and understand) the natural phenomena and processes on the Earth.
This satellite was originally scheduled to be launched in March 2024, but due to some required technical modifications, the satellite underwent a hardware upgrade. The interesting point to note is that the satellite has been manufactured at the Jet Propulsion Laboratory (JPL) in California, United States. Still, the site for its launch was chosen to be the Satish Dhawan Space Centre, ISRO in India. At the JPL, a reflective coating was added to the satellite to mitigate the risk of overheating during its mission. The duration of this mission is approximately three years. The satellite, after being reworked, was carried by NASA’s own C-130 from the Wallops flight facility in Virginia. After multiple stopovers in Hawaii and the Philippines, it reached Bengaluru in India.
As per NASA, “NISAR is a joint Earth-observing mission between NASA and the Indian Space Research Organization (ISRO) with the goal to make global measurements of the causes and consequences of land surface changes using advanced radar imaging. This mission concept and the resulting partnership are in response to the National Academy of Science’s 2007 survey of Earth observational priorities for the next decade, known as the decadal survey. One of the top priorities identified in this survey was to gain data and insight in three Earth science domains: ecosystems, deformation of Earth’s crust and cryospheric sciences.”
In 2014, ISRO and NASA signed an agreement to collaborate and partner with each other to launch NISAR. The agreement was formalised on September 30 2014. The signatories to this joint Earth-observing satellite mission included ISRO’s then Chairman, Dr. K Radhakrishnan, and NASA’s administrator Charles Bolden. The NISAR mission was intended to establish a pathway for many joint bilateral space operations in the future. The unique feature of this mission is that it will be the first satellite mission to use two different radar frequencies, i.e., the L-Band and the S-Band. This will help measure the changes occurring on the Earth’s surface over a range of one centimetre. While NASA has provided the L-Band synthetic aperture radar, ISRO has provided the S-Band radar.
Similarly, ISRO is provided the spacecraft bus, the launch vehicle, as well as the various other associated launch services.
NISAR’s launch was aboard the ISRO’s Geosynchronous Satellite Launch Vehicle (GSLV-F16) from the Satish Dhawan Space Centre (SDSC) at Sriharikota. This launch is considered one of the most precise launches ever. The reason is that this five-stage rocket has operated flawlessly at every stage. It was successful in injecting the satellite into its precise orbit with a margin of just two to three kilometres. The NISAR satellite will be circling the Earth fourteen times every day. By this, it would be able to scan nearly all the Earth’s land and ice surfaces twice every 12 days.
This earth-observation satellite would detect even minute changes on the land, sea, ice and in vegetation. It will also allow the decision-makers to respond quickly to any natural disasters and map farmlands to improve crop output. It will also be observing the Earth with a swath of 242 km and a very high spatial resolution. For this task, SweepSAR technology has been used for the first time. As per ISRO, “NISAR can detect even small changes on the earth’s surface, such as ground deformation, ice sheet movement, and vegetation dynamics. Further applications include sea ice classification, ship detection, shoreline monitoring, storm characterisation, changes in soil moisture, mapping and monitoring of surface water resources, and disaster response”.
The successful launch of NISAR has come as a major relief to ISRO’s efforts to launch this satellite. Since 2024, multiple reschedules for ISRO’s other missions, such as the PSLV-C61/EOS-09 mission on May 18, 2025, due to a technical glitch, have marred ISRO’s satellite efforts. To sum it up, NISAR’s launch is a crucial chapter in the Indo-US space cooperation, which started way back in the year 1963 when the United States supplied India with the Nike-Apache sounding rockets, which were launched from Thumba in Trivandrum, Kerala, on November 21 1963, thereby marking the advent of the Indian space program. NISAR’s success would be further analysed once it completes its mission in the next three years.
