NISAR: Joint Earth Observing Mission of NASA and ISRO

• 30 Mar 2021

Why in News

NASA and ISRO are collaborating on developing an SUV-sized satellite called NISAR, which will detect movements of the planet’s surface as small as 0.4 inches over areas about half the size of a tennis court.

• The satellite will be launched in 2022 from the Satish Dhawan Space Center in Sriharikota (Andhra Pradesh) into a near-polar orbit.

Key Points

• The Name ‘NISAR’: The name NISAR is short for NASA-ISRO-SAR.
  
  • SAR here refers to the Synthetic Aperture Radar that NASA will use to measure changes in the surface of the Earth.
  • It 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.
• Function: It will scan the globe every 12 days over the course of its three-year mission of imaging the Earth’s land, ice sheets and sea ice to give an unprecedented view of the planet.
• Role of NASA:
  
  • National Aeronautics and Space Administration (NASA - space agency of the USA) will provide one of the radars for the satellite, a high-rate communication subsystem for science data, GPS receivers and a payload data subsystem.
  • NISAR will be equipped with the largest reflector antenna ever launched by NASA.
• Role of ISRO:
  
  • Indian Space and Research Organisation (ISRO) will provide the spacecraft bus, the second type of radar (called the S-band radar), the launch vehicle and associated launch services.
• Primary Goals:
  
  • Tracking subtle changes in the Earth’s surface,
  • Spotting warning signs of imminent volcanic eruptions,
  • Helping to monitor groundwater supplies, and
  • Tracking the rate at which ice sheets are melting.
• Expected Benefits:
  
  • NISAR's data can help people worldwide better manage natural resources and hazards, as well as providing information for scientists to better understand the effects and pace of climate change.
    • 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.
  • It will also add to our understanding of our planet's hard outer layer, called its crust.

S-Band Radar

• S band radars operate on a wavelength of 8-15 cm and a frequency of 2-4 GHz.
• Because of the wavelength and frequency, S-band radars are not easily attenuated. This makes them useful for near and far range weather observation.
• The drawback to this band of radar is that it requires a large antenna dish and a large motor to power it. It is not uncommon for a S-band dish to exceed 25 feet in size.

Source: IE