What is NISAR?

• NISAR (NASA-ISRO Synthetic Aperture Radar) is an Earth-observation satellite jointly developed by U.S. space agency NASA and ISRO under a partnership agreement signed in 2014. 
• The 2,800 kilograms satellite consists of both L-band and S-band synthetic aperture radar (SAR) instruments, which makes it a dual-frequency imaging radar satellite.
• While NASA has provided the L-band radar, GPS, a high-capacity solid-state recorder to store data, and a payload data subsystem, ISRO has provided the S-band radar, the GSLV launch system and spacecraft.
• Another important component of the satellite is its large 39-foot stationary antenna reflector. Made of a gold-plated wire mesh, the reflector will be used to focus the radar signals emitted and received by the upward-facing feed on the instrument structure.

What is the mission?

• Once launched into space, NISAR will observe subtle changes in Earth’s surfaces, helping researchers better understand the causes and consequences of such phenomena. 
• Designed as a low earth orbit (LEO) observatory, NISAR will map the entire globe in 12 days and provide spatially and temporally consistent data for understanding changes in Earth’s ecosystems, ice mass, vegetation biomass, sea level rise, groundwater and natural hazards, including earthquakes, tsunamis, volcanoes and landslides.
• Synthetic Aperture Radar refers to a technique for producing high-resolution images. Because of the precision, the radar can penetrate clouds and darkness, which means that it can collect data day and night in any weather.

Why in News?

• The ambitious NISAR mission has encountered a slight delay, pushing back the launch to the second half of the year.
• The mission will be launched from Sriharikota’s Satish Dhawan Space Centre, onboard ISRO’s Geosynchronous Satellite Launch Vehicle Mark 2.