ISRO-NASA develops radar for joint earth observation satellite mission

The Indian Space Research Organisation- ISRO with the US space agency NASA completed the development of a Synthetic Aperture Radar- SAR which is capable of producing extremely high-resolution images for a joint Earth observation satellite mission.

NASA-ISRO SAR (NISAR) is a joint collaboration between both the space agencies for a dual-frequency L and S-band SAR for earth observation. NASA and ISRO had signed a partnership in 2014 to collaborate and launch NISAR.

The Earth Observation Satellite Mission has been targeted to launch in early 2022 from the Sriharikota spaceport of ISRO in Andhra Pradesh.

What is NISAR?

NISAR by both the space agencies will be the first satellite mission to use two different radar frequencies (S-band and L-band) for measuring the changes in Earth’s surface less than a centimeter across.

NASA and ISRO develop radar:

The National Aeronautics and Space Administration- NASA has been providing L-band SAR of the mission, GPS receivers, a high-rate communication subsystem for the science data, payload data subsystem, and a solid-state recorder.

While ISRO is providing the S-band SAR, the spacecraft bus, the associated launch services, and the launch vehicle for the mission. Its goal is to make global measurements of the consequences and causes of the land surface changes with the use of advanced radar imaging.

Functions of NISAR:

• NISAR will provide a means of disentangling highly complex processes ranging from ice sheet collapses to ecosystem disturbances as well as natural hazards including tsunamis, earthquakes, landslides, and volcanoes.

• The mission will be measuring the Earth’s dynamic surfaces, changing ecosystems, and ice masses. It will provide information about natural hazards, biomass, groundwater, and sea-level rise and will also support a host of other applications.

• NISAR will observe the ice-covered and land surfaces of Earth globally with 12-day regularity, will sample Earth on average every six days for a baseline 3-year mission.

• This will also allow the mission to observe the large range of Earth processes from the ice sheets and flow rates of glaciers to the dynamics of volcanoes and earthquakes.

Use of SAR to produce high-resolution images:

A sophisticated information processing technique known as SAR is used by NISAR in order to produce extremely high-resolution images. The radar will penetrate darkness and clouds which will enable NISAR to collect data day and night in any form of weather.

Over the multiple orbits, the radar images will be allowing users to track changes in hazard sites and croplands, as well as monitor the ongoing crisis. The radar images will also be detailed enough to show local changes and broad enough for measuring regional trends.

Better understanding of land surface changes:

As the mission will continue for years, the data collected will allow a better understanding of the consequences and causes of the land surface changes. It will also increase the ability to manage the resources and also prepare for global change.

NASA will require a minimum of 3 years of operations with the L-band radar and ISRO will require 5 years of operations with the S-band radar over the target areas in India and the Southern Ocean.