ISRO Chairman K Sivan. | Photo: PTI
The Indian Space Research Organsiation (ISRO) S-Band SAR Payload of NASA-ISRO
Synthetic Aperture Radar (NISAR) mission was flagged off on March 4.
SAR (NISAR) Mission scheduled to be launched by the Indian Space Research Organsisation (Isro) in 2022 will measure the Earth’s changing ecosystems, dynamic surfaces, and ice masses providing information about biomass, natural hazards, sea level rise, and groundwater, and will support a host of other applications. NISAR is planned to be launched in 2022 from Satish Dhawan Space Center at Sriharikota in India, into a near-polar orbit. NASA
requires a minimum of three years of global science operations with the L-band radar, and ISRO
requires five years of operations with the S-band radar over specified target areas in India and the Southern Ocean.
ISRO’s S-Band NISAR mission was flagged off by ISRO chairman and secretary, Department of Space on March 4, 2021 through virtual mode. The S-Band SAR payload has been shipped from Space Applications Centre, Ahmedabad (SAC/ISRO) to Jet Propulsion Laboratory, Pasadena for integration with L-Band SAR Payload of JPL, NASA.
NISAR is a joint project between NASA
and ISRO to measure Earth’s changing ecosystem. It is expected to be the world’s most expensive Earth-imaging satellite.
The total cost of the project includes Isro's work share cost of about Rs 788 crore and the cost of JPL's work share of about $808 million
NISAR would provide a means of disentangling highly spatial and temporally complex processes ranging from ecosystem disturbances to ice sheet collapses and natural hazards including earthquakes, tsunamis, volcanoes and landslides.
On September 30, 2014, NASA and ISRO signed a partnership to collaborate on and launch NISAR. The mission is expected to be launched in early 2022. NASA is providing the mission’s L-band SAR, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO is providing the spacecraft bus, the S-band radar, the launch vehicle and associated launch services.
NISAR is a joint Earth-observing mission between NASA and ISRO aimed at making 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.
NISAR is the first satellite mission that will collect radar data in two microwave bandwidth regions, called the L-band and the S-band, to measure changes of less than a centimeter across in our planet's surface. This allows the mission to observe a wide range of Earth processes, from the flow rates of glaciers and ice sheets to the dynamics of earthquakes and volcanoes.
NISAR uses a sophisticated information-processing technique known as SAR to produce extremely high-resolution images. Radar penetrates clouds and darkness, enabling NISAR to collect data day and night in any weather. The instrument's imaging swath — the width of the strip of data collected along the length of the orbit track — is greater than 150 miles (240 kilometers), which allows it to image the entire Earth in 12 days.
Over the course of multiple orbits, the radar images will allow users to track changes in croplands and hazard sites, as well as monitor ongoing crises such as volcanic eruptions. The images will be detailed enough to show local changes and broad enough to measure regional trends. As the mission continues for years, the data will allow for better understanding of the causes and consequences of land surface changes, increasing our ability to manage resources and prepare for and cope with global change.
The NISAR spacecraft will accommodate two fully capable SAR instruments (24 cm wavelength L-SAR and 10 cm wavelength S-SAR), each designed as array-fed reflectors to work as SweepSAR scan-on-receive wide swath mapping systems. The spacecraft will be launched on an ISRO GSLV-II launch vehicle into a polar sun-synchronous dawn dusk orbit.
NASA's contributions include the L-band SAR instrument, including the 12-m diameter deployable mesh reflector and 9-m deployable boom and the entire octagonal instrument structure. In addition, NASA is providing a high capacity solid-state recorder (approximately 9 Tbits at end of life), GPS, 3.5 Gbps Ka-band telecom system, and an engineering payload to coordinate command and data handling with the ISRO spacecraft control systems. ISRO is providing the spacecraft and launch vehicle, as well as the S-band SAR electronics to be mounted on the instrument structure.