NISAR Mission

NISAR is a joint Earth-observing mission by NASA and ISRO. The mission aims at co-developing a dual-frequency synthetic aperture radar on an Earth observation satellite.

The NASA-ISRO SAR mission will observe Earth and measure its changing ecosystem and masses globally. It is the world’s most expensive imaging-satellite and the two space agencies intend to launch the satellite by 2022.

Given below are all the important aspects of the NISAR mission:

This satellite and especially the NASA-ISRO SAR mission is extremely important for aspirants preparing for the upcoming IAS Exam. 

To study in detail about the Indian Space Research Organisation (ISRO), candidates can visit the linked article. 

Furthermore, in this article, we shall be discussing in detail the NISAR mission and its significance in the Indian and International Space achievements. 

What is a Synthetic Aperture Radar

Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes.

SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars. SAR is typically mounted on a moving platform, such as an aircraft or spacecraft, and has its origins in an advanced form of side looking airborne radar (SLAR).

The distance the SAR device travels over a target during the period when the target scene is illuminated creates the large synthetic antenna aperture (the size of the antenna). Typically, the larger the aperture, the higher the image resolution will be, regardless of whether the aperture is physical (a large antenna) or synthetic (a moving antenna) – this allows SAR to create high-resolution images with comparatively small physical antennas.

For a fixed antenna size and orientation, objects which are further away remain illuminated longer – therefore SAR has the property of creating larger synthetic apertures for more distant objects, which results in a consistent spatial resolution over a range of viewing distances.

To create a SAR image, successive pulses of radio waves are transmitted to “illuminate” a target scene, and the echo of each pulse is received and recorded. The pulses are transmitted and the echoes received using a single beam-forming antenna, with wavelengths of a meter down to several millimeters. As the SAR device on board the aircraft or spacecraft moves, the antenna location relative to the target changes with time.

An Overview of the NISAR Mission

NISAR is the world’s most expensive Earth-imaging satellite. Being a combined US-India satellite, the mission becomes even more important as it is scheduled to launch from Indian soil.

The key factors and characteristics of the mission are given below:

• It is a dual-frequency Radar imaging satellite and is using both L-Brand and S-Brand Radar frequencies. The S-Brand Radar is being built by ISRO and the L-Brand Radar is being built by NASA
• The satellite is likely to be launched from Indian soil. The launch site is Satish Dhawan Space Center or Sriharikota Range, Andhra Pradesh
• The main objective of this research is to make global measurements of the causes and consequences of land surface changes. This includes:
  • Imbalance in the Ecosystem
  • Natural Hazards
  • Ice Sheet Collapse
  • Agricultural and Forest Biomass
  • Soil Moisture Estimation
• The mission is also expected to open up paths for the future joint mission between the two Space Agencies

Conclusively, the mission is expected to study the Earth from space in terms of the future global environmental aspect. 

Aspirants can also refer to the articles below, to learn in detail about the other important Indian and International space missions, satellites, and agencies:

Societal Relevance of NISAR Mission

As discussed earlier, the NISAR Mission mainly aims at studying the elements of Earth from an observing satellite. This space mission will benefit its multiple applications. Discussed below are the same in detail:

• Life and Civilisation: NISAR will provide maps of surface soil moisture globally every 6 to 12 days at the spatial scale of individual farm fields. This offers unprecedented detail and is vital for monitoring the habitats of plants, animals, and humans
• Damage Mapping: The NISAR satellite mission can provide maps and images of any disturbance which may lead to a natural disaster. Within hours to days of natural disasters like major earthquakes, hurricanes, tsunamis, and landslides, the NISAR satellite will present its observations which will rapidly provide information for rescue operations, economic loss estimates, and the health of the critical infrastructure.
• Protecting water and Oil Spills: Every year emergency responders work to prevent hundreds of oil and chemical spills from harming people and the environment. Rapid identification of spilled oil in the vast open waters of the oceans and gulf is key to minimizing damage, and radar remote sensing can provide the necessary information.
• Glaciers and Ice Sheet: Observations of the flow of Earth’s ice sheets and glaciers are critical to understanding current and future rates of sea-level rise. Synthetic aperture radar can serve as a ‘radar speed gun’ to provide global maps of ice flow in support of sea-level rise impact assessments
• Marine Hazards: NISAR will provide information used to monitor ocean wind, waves, and sea-ice extent that can aid weather forecasting and warn of marine hazards. Its coverage of coastal oceans benefits sea transportation and coastal communities.
• Flood Forecasting: Flood forecasting informs downstream communities if a flood is coming and how much flooding to expect. Like a virtual stream gauge, synthetic aperture radar is able to measure changing water levels in standing vegetation as floodwaters from heavy upriver rains head downstream.
• Protecting Forest Resources: NISAR is designed to monitor global forest extent and quality and to provide accurate and timely information on forest volume and products for sustainable development and management of ecosystem goods and services.

This mission will prove to be a boon for both ISRO and NASA in terms of their space mission and a boon to humanity and livelihood as the SAR will be able to notify any hazardous disturbance in the Earth’s surface days prior to a disaster or calamity.

Civil Services Exam aspirants must also note that this concept is important from the perspective of the Science and Technology syllabus and questions based on the same may be asked. Thus, to get detailed UPSC Notes on Science and Technology, candidates can visit the linked article. 

For any further UPSC exam updates, or study material and notes, visit BYJU’S.