SPACE TECHNOLOGY

Indian National Satellite (INSAT) System

The Indian National Satellite System or INSAT is a series of multipurpose geostationary satellites launched by ISRO to satisfy telecommunications, broadcasting, meteorology, and search and rescue operations. Commissioned in 1983, INSAT is the largest domestic communication system in the Indo-Pacific Region.

It is a joint venture of the Department of Space, Department of Telecommunications, India Meteorological Department, All India Radio, and Doordarshan. The overall coordination and management of the INSAT system rest with the Secretary-level INSAT Coordination Committee.

INSAT satellites provide transponders in various bands to serve the television and communication needs of India. Some of the satellites also have Very High-Resolution Radiometers (VHRR), and CCD cameras for meteorological imaging.

INSAT-3D is one of three satellites under development by ISRO exclusively to improve domestic weather forecasting and track cyclones and monsoons originating from the Bay of Bengal and the Arabian Sea.                                           

The instrument comprises a six-channel imaging radiometer designed to measure radiant and solar reflected energy from areas sampled on the Earth and a high-resolution infrared sounder to measure vertical temperature profiles, humidity, surface and cloud top temperatures, and ozone distribution.

INSAT-3D was flown on July 26, 2013, with a lift of mass of about 2100 kg by ARIANE-5/GSLV-MK II /Soyuz launcher and the expected minimum mission life is seven years for deployment in a 38; 500km equatorial plane geostationary orbit.

This orbit will provide a continuous stationary view over the Indian Ocean for regular observations of cloud patterns and monitoring of the path of tropical cyclone formations to predict the time and place of landfall for disaster warnings. The INSAT-3D sounder instrument measures radiation using 19 precision narrow-band pass interference filters to isolate and discriminate between spectral bands.

ISRO’s first satellite, Aryabhata, was launched by the Soviet Union on April 19, 1975. Rohini, the first satellite to be placed in orbit by an Indian-made launch vehicle (the Satellite Launch Vehicle 3), was launched on July 18, 1980.

ISRO has launched several space systems, including the Indian National Satellite (INSAT) system for telecommunication, television broadcasting, meteorology, and disaster warning, and the Indian Remote Sensing (IRS) satellites for resource monitoring and management. The first INSAT was launched in 1988, and the program expanded to include geosynchronous satellites called GSAT.

Indian Remote Sensing Satellite System

India’s remote sensing program under the Indian Space Research Organization (ISRO) started off in 1988.

 IRS-1A, the first of the series of indigenous state-of-art operating remote sensing satellites, was successfully launched into a polar sun-synchronous orbit on March 17, 1988, from the Soviet Cosmodrome at Baikonur.                                                        

IRS-1A was followed by the launch of IRS-1B, an identical satellite, in 1991. IRS-1A and 1B in tandem provided 11-day receptivity. These two satellites in the IRS series have been the workhorses for generating natural resource information in a variety of application areas, such as agriculture, forestry, geology, hydrology, etc.

The series of IRS spacecraft was launched with enhanced capabilities in payloads and satellite platforms. The whole gamut of the activities from the evolution of IRS missions by identifying the user requirements to the utilization of data from these missions by user agencies is monitored by National Natural Resources Management System (NNRMS).

Apart from meeting the general requirements, the definition of IRS missions based on specific thematic applications like natural resources monitoring, ocean, and atmospheric studies, and cartographic applications resulted in the realization of theme based satellite series, namely,

(i) Land/water resources applications (RESOURCES series and RISAT series);

(ii) Ocean/atmospheric studies (OCEANS series, INSAT-VHRR, INSAT-3D, Megha-Tropiques, and SARAL); and

(iii) Large-scale mapping applications (CARTOSAT series).                        

IRS-1A development was a major milestone in the IRS program. It is important to look back at the achievements of the Indian Space Programme, particularly in remote sensing applications, wherein India has become a role model for the rest to follow. 

Polar Satellite Launch Vehicle (PSLV)

The Polar Satellite Launch Vehicle (PSLV) is the third generation launch vehicle of India. It is the first Indian launch vehicle to be equipped with liquid stages. After its first successful launch in October 1994, PSLV emerged as the reliable and versatile workhorse launch vehicle of India with 39 consecutively successful missions by June 2017.

PSLV represents ISRO’s first attempt to design and develop an operational vehicle that can be used to orbit remote sensing satellites. PSLV is capable of launching a 1750 kg satellite in a 620 km sun-synchronous polar orbit, a 1050 kg satellite n a geosynchronous transfer orbit, or a 3500 kg class satellite into /a low Earth Orbit.

In the standard configuration, it measures 44.4m tall, with a lift-off weight of 295 tonnes. The first stage is one of the largest solid propellant boosters in the world and carries 139 tonnes of propellant. A cluster of six strap-ons is attached to the first stage motor, four of which are ignited on the ground and two are air-lit.                    

During the 1994-2017 period, the vehicle launched 48 Indian satellites and 209 satellites for customers from abroad. Besides, the vehicle successfully launched two spacecraft – Chandrayaan-1 in 2008 and Mars Orbiter Spacecraft in 2013 – that later traveled to Moon and Mars respectively.

PSLV has repeatedly proved its reliability and versatility by launching 39 satellites/spacecraft (17 Indian and 22 International customers) into a variety of orbits so far (till April 2010). In the Chandrayaan-I mission, with an extended version of Strap-on motors, PSOM-XL, the payload capability was enhanced to 1750 kg in a 620 km Polar Sun Synchronous Orbit. PSLV has rightfully earned the status of workhouse launch vehicle of ISRO. 

Geosynchronous Satellite Launch Vehicle (GSLV)

A Geosynchronous Satellite Launch Vehicle (GSLV) is an expendable launch system operated by the Indian Space Research Organisation (ISRO). GSLV was used in thirteen launches from 2001 to 2018, with more launches planned. The GSLV is capable of launching a 2,000 kg class satellite into a Geosynchronous Transfer Orbit (GTO). It is a three-stage vehicle, 49 m tall, with 414t lift-off weight.

It has a maximum diameter of 3.4 m at the payload fairing. The first stage comprises S139 solid booster with four liquid (L40) strap-ons. The second stage (GS2) is a liquid engine and the third stage (GS3) is a cyro stage.              

The first flight of GSLV took place from SHAR on 18 April 2001 by launching 1540 kg GSAT-1. It was followed by five more launches, GSLV-D2 on 8 May 2003 (GSAT-2 1825 kg); GSLV-F 01 on 20 September 2007 (INSAP4 CR 2130 kg). Till now, GSLV has launched four satellites. Preparations for the launch of GSLV-D3 carrying indigenous cryogenic engine are in an advanced stage.

GSLV-Mk III, a new version of GSLV capable of launching spacecraft weighing up to 4 tonnes to GTO, is under development.

  • What are the major services provided by INSAT?

The Indian National Satellite System or INSAT is a series of multipurpose geostationary satellites launched by ISRO to satisfy telecommunications, broadcasting, meteorology, and search and rescue operations. Commissioned in 1983, INSAT is the largest domestic communication system in the Indo-Pacific Region.                                 

a. Being a multipurpose satellite, the INSAT serves many important sectors of the Indian economy. Foremost amongst them is the Telecommunication sector wherein INSAT is providing Mobile Satellite Service besides providing VSAT services.

b. Similarly, INSAT has been a major catalyst for the expansion of television coverage in India. Satellite television now covers 100% area and 100% population, the terrestrial coverage is over 65 percent of the Indian land mass and over 90 percent of the population.

c. In addition to this, social development through exclusive channels for training and developmental education has become possible through INSAT.

d. A Telemedicine network to take super specialty medical services to the remote and rural population has become a reality.

e. The launch of EDUSAT, India’s first thematic satellite dedicated exclusively to educational services has provided a further fillip to the educational services offered by the INSAT system.

f. INSAT system is also providing meteorological Radiometer and CCD cameras on some of its spacecraft. This apart, cyclone monitoring through meteorological imaging and issue of warnings on impending cyclones through disaster warning receivers have been operationalized.

  • What are the future Space Missions of ISRO?
  • ASTROSAT, the first dedicated Indian space astronomy mission for simultaneous multi-wavelength observations of stellar and galactic sources.                                            
  • Chandrayaan-2, a logical extension of Chandrayaan-1 to carry out in-situ analysis of lunar samples and study lunar surface properties using instruments onboard Orbiter and Rover.
  • YOUTHS, a mini-satellite to study the impact of Sun and Space Weather.
  • Megha-Tropiques, to study the convective systems that influence tropical weather and climate.
  • Several small satellite missions like ADITYA-1 (Solar coronagraph), X-ray Polarimeter Experiment (POLIX), Infra-Red Spectroscopic Imaging Survey (IASIS), SENSE, P/E (Satellite for Earth’s Near Space Environment) and 1-STAG (Indian Satellite for Aerosol and Gases) are also on the anvil.

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