UPSC Express

In focus: Risat-2B

Introduction

• Risat-2B is the 3^rd satellite to be launched in the Risat series after Risat-1 and Risat-2 launched in 2009 and 2012 respectively.
• It is a radio imaging earth observation satellite.
• It is placed in a 37-degree inclined Sun-synchronous polar orbit at a height of 555 km from earth surface.

Specification

• Radio imaging satellite with X-band synthetic aperture radar (SAR)
• Expected life: 5 Years
• 6m unfurlable radial rib antenna
• The resolution of Risat-2B is less than 1 metre.

Features

• The X-band SAR enables all-weather, day-night radio communication.
• The unfurlable radial rib antenna technology (mobile communication) is primarily used to receive signals, modify them and retransmit back to a hand-held receiver on Earth.

Applications

• The primary goal of Risat-2B is to boost India’s surveillance and strike capabilities.
  • Will be used to monitor activities across the border and in Indian Ocean.
  • Will help in arresting infiltration by terrorists
  • Will help in planning preemptive strikes on terror launchpads like surgical strikes and Balakot aerial strike.
• Other applications include agriculture, forestry and disaster management support.

In brief: Risat Series

Introduction

• Risat is short for radio imaging remote sensing satellite series of India.
• They act as India’s ‘eyes in the sky’ and thus extremely significant in surveillance and reconnaissance efforts.

Concept

• While an optical remote sensing uses light reflected by objects on earth surface to ‘sense and observe’, radio imaging remote sensing satellites beam a radio signal on the earth’s surface and ‘senses’ the radio signal reflected back.
• As a result, radio imaging satellites are capable of remote sensing even at night or cloud cover or rain.

Risat series

• ISRO has launched 3 satellites in the Risat series so far.
• 2009 – Risat 2 – Launched in the aftermath of 26/11 Mumbai terror attack
• 2012 – Risat 1- Assisted planning of the 2016 surgical strike along with Cartosat-2
  • Risat 2 was launched earlier as the indigenous C-band SAR to be used for RISAT-1 was not ready
• 2019 – Risat 2B – Stepping up C4ISR security architecture
• Further, ISRO has planned a dozen satellites in the Risat series by end of 2020 with 5 more in 2019.
• The 5 Risat-series satellites due to be launched in 2109 include Risat-2BR1, Risat-2BR2, Risat-1A, Risat-1B and Risat-2A.