RISAT (Radar Imaging Satellite) is a series of Indian radar imaging

reconnaissance satellite A reconnaissance satellite or intelligence satellite (commonly, although unofficially, referred to as a spy satellite) is an Earth observation satellite or communications satellite deployed for military or intelligence applications. The ...

s built by

ISRO The Indian Space Research Organisation (ISRO; ) is the national space agency of India, headquartered in Bengaluru. It operates under the Department of Space (DOS) which is directly overseen by the Prime Minister of India, while the Chairman ...

. They provide all-weather

surveillance Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing or directing. This can include observation from a distance by means of electronic equipment, such as c ...

using synthetic aperture radars (SAR). The ''RISAT'' series are the first all-weather

Earth observation satellite An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, me ...

s from ISRO. Previous Indian observation satellites relied primarily on optical and spectral sensors which were hampered by

cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds on average when observed from a particular location. Okta is the usual unit for measurement of the cloud cover. The cloud co ...

. After the 26 November 2008,

2008 Mumbai attacks The 2008 Mumbai attacks (also referred to as 26/11, pronounced "twenty six eleven") were a series of Terrorism, terrorist attacks that took place in November 2008, when 10 members of Lashkar-e-Taiba, an Islamist terrorist organisation from P ...

, the launch plan was modified to launch RISAT-2 before RISAT-1, since the indigenous C-band SAR to be used for RISAT-1 was not ready. RISAT-2 used an Israel Aerospace Industries (IAI) X-band SAR sensor similar to the one employed on

TecSAR TecSAR-1, also known as TechSAR, Polaris and Ofeq-8, is an Israeli reconnaissance satellite, equipped with a synthetic-aperture radar (SAR) developed by Elta Systems. It was successfully launched at 03:45 UTC on 21 January 2008, by PSLV C- ...

Satellites

RISAT 2

RISAT-2 was the last of the RISAT series to reach orbit. It was launched successfully on April 20, 2009 at 0015 hours GMT by a PSLV rocket. The 300-kg satellite was built by ISRO using a X-band SAR manufactured by IAI. This satellite was fast tracked in the aftermath of the 2008 Mumbai attacks. The satellite will be used for border surveillance, to deter insurgent infiltration and for anti-terrorist operations. It is likely to be placed under the Aerospace Command of the

Indian Air Force The Indian Air Force (IAF) is the air arm of the Indian Armed Forces. Its complement of personnel and aircraft assets ranks third amongst the air forces of the world. Its primary mission is to secure Indian airspace and to conduct aerial w ...

. No details of the technical specifications of RISAT-2 have been published. However, it is likely to have a spatial resolution of about a metre or so. Ship detection algorithms for radar satellites of this class are well-known and available. The satellite also has applications in the area of disaster management and agriculture-related activities.

RISAT 1

RISAT-1 was an indigenously developed radar imaging satellite successfully launched by a PSLV-XL rocket on April 26, 2012 from Satish Dhawan Space Centre, Shriharikota. RISAT-1 was postponed in order to prioritize the building and launch of RISAT-2. The features of RISAT-1 include: * 160 x 4 Mbit/s data handling system * 50 Newton-meter-second reaction wheels * SAR antenna deployment mechanism * Phased array antenna with dual polarisation

RISAT 2B

RISAT-2B RISAT-2B, or Radar Imaging Satellite-2B is an Indian radar reconnaissance satellite that is part of India's RISAT programme and the third satellite in the series. It is built by Indian Space Research Organisation (ISRO) to replace RISAT-2. ...

is an indigenously developed Synthetic Aperture Radar (SAR) imaging satellite operating in X Band with 3.6 m radial rib antenna. It was launched by PSLV C46 (Core Alone) on 22 May 2019 at 0000 (UTC) from First Launch Pad of SDSC (SHAR). The satellite has the capability to operate in different modes including Very High Resolution RADAR imaging modes of 1m × 0.5m resolution and 0.5m × 0.3m resolution. RISAT-2B is placed in an inclined orbit for better revisit rates over area of interest. Being Radar Imaging satellite, it can image during day / night / all weather conditions. The Satellite will be utilized for high resolution spot imaging of locations of interest. * Mass: 615 kg * Orbit: 557 km (circular) at inclination of 37° * Mission life: 5 years

RISAT 2BR1

RISAT-2BR1 is an Indian radar reconnaissance satellite that is part of India's RISAT programme and the fourth satellite in the series. It is built by

Indian Space Research Organisation The Indian Space Research Organisation (ISRO; ) is the national space agency of India, headquartered in Bengaluru. It operates under the Department of Space (DOS) which is directly overseen by the Prime Minister of India, while the Chairman ...

(ISRO). It was launched on 11 December 2019 at 3:25 PM IST on board PSLV rocket from Satish Dhawan Space Centre. The satellite has resolution of 0.35 meters by which two objects separated by distance of 0.35 metres can be distinctly identified. The mission duration is planned to be 5 years. It is the 50th launch of Polar Satellite Launch Vehicle and 75th launch from Satish Dhawan Space Centre. * Mass: 628 kg * Orbit: 560 km * Mission life : 5 years

Launch schedule

References

{{DEFAULTSORT:Risat Space programme of India Earth observation satellites of India Synthetic aperture radar satellites Satellite series