NASA-ISRO Synthetic Aperture Radar satellite (NISAR) is the world’s most expensive earth imaging satellite.
NISAR is dual frequency RADAR, it is an L-band and S-band RADAR. It is the first such satellite using dual frequency RADAR.
The S-band is being built by ISRO and L-band by NASA.
It is expected that the NISAR satellite will be launched in 2021 from India using the Geo-synchronous Satellite Launch Vehicle (GSLV).
One of the main purposes of the mission is to observe Earth and establish a general pathway for future joint missions for Mars exploration
It will take weekly snapshots of earth that will provide time lapse images of the motion of tectonic plates, ice sheets and changes in vegetation over land in agriculture and forests.
NISAR will provide a means of resolving highly spatial and temporally complex processes ranging from ecosystem disturbances, to ice sheet collapse and natural hazards including earthquakes, tsunamis, volcanoes, and landslides.