UPSC IAS exam preparation - Technology and environmental issues in India - Lecture 12

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Space technology

1.0 Introduction

The Indian Space Programme began in 1962. In 1969 the Indian space Research Organization (ISRO) was set up with headquarters in Benguluru for the purpose of rapid development in space technology and its application. In 1972, the Space Commission was established. In 1975, India launched its first satellite, Aryabhatta, and thus entered the space age. The primary objective of the Indian Space Programme is to achieve self-reliance in space technology and evolve application programmes to meet national developmental needs.

Over the last two and half decades, the Indian space programme has made impressive progress through a well integrated, self-reliant programme. Its main objectives are (1) Mass Communication and education via satellite, (2) Survey and management of natural resources through remote sensing technology, environmental monitoring and meteorological forecasting and (3) Development of indigenous satellites and satellite launch vehicles.

2.0 ORGANISATIONAL FRAMEWORK

Indian Space Research Organization: Indian Space Research Organization (ISRO), set up in 1969 at Ahmedabad with Prof. Vikram Sarabhai as chairman, is the apex body to provide guidelines, formulate policies and monitor implementation of the national space policy.

2.1 Other organizations

Vikram Sarabhai Space Centre (VSSC): VSSC at Thiruvananthapuram is the head center for the development of satellite launch vehicles and associated technology.
ISRO Satellite Centre (ISAC): ISAC at Banglore is the lead center for developing satellite technology and implementation of satellite system for scientific technological and applications missions.
Satish Dhawan Space Centre (SDSC) SHAR: SDSC Sriharikota is the main launch center of ISRO and has facilities for solid propellant casting, static testing of solid motors, launch vehicles integration and launch operations, range operation comprising telemetry tracking and command network and mission control center.
Liquid Propulsion System Centre (LPSC): LPSC is the lead centre in development of liquid and cryogenic propulsion for launch vehicles and satellites.
Space Applications Centre (SAC): SAC at Ahmedabad is engaged in the development of pay loads for communication, meteorological and remote sensing satellites.
Development and Educational Communication Unit (DECU): DECU at Ahmedabad is involved in the conception, definition, planning, implementation and socio-economic evaluation of innovative configuration for space applications.
ISRO Telemetry, Tracking and Command Network (ISTRAC): ISTRAC provides mission support to low-earth orbit satellites as well as launch vehicle missions.
Master Control Facility: MCF at Hassan in Karnataka and Bhopal in Madhya Pradesh monitors and controls all the geo-stationary satellites of ISRO.
ISRO Inertial System Unit (IISU): IISU at Thiruvanathpuram carries out resource and development in inertial sensors and systems.
National Remote Sensing Agency (NRSA): NRSA at Hyderabad is an autonomous institution under DOS. The agency is responsible for satellite data acquisition and processing data dissemination, aerial remote sensing and decision support for disaster management.
Physical Research Laboratory (PRL): PRL at Ahmedabad, is an autonomous institution supported mainly by DOS. It is premier institute for multi-disciplinary research in astronomy and astrophysics, earth sciences, planetary sciences, space sciences and basic science.
National Atmospheric Research Laboratory (NARL): NARL at Gadanki near Tirupati is an autonomous society supported by DOS. It is a premier centre for atmospheric research facilities like Mesosphere, Stratosphere, Troposphere radar, LIDAR etc.
Regional Remote Sensing Service Centres: (PRSSC) - Five PRSSCs have been established by the DOS at Banglore, Jodhpur, Kharagpur, Dehradun and Nagpur. PRSSCs support the various remote sensing tasks specific to their regions as well as at the national level.
North Eastern - Space Application Centre (NE SAC): NE-SAC, located at Shillong, is a joint initiatives of DOS and North Eastern Council to provide development support to the North Eastern region using space science and technology.
Antrix Corporation Limited: The Antrix Corporation Limited, Banglore is the apex marketing agency under DOS with access to resources of DOS as well as Indian space industries.
Semi-Conductor Laboratory (SCL): SCL is entrusted with design and development of very large scale integration ( VLSI) devices and development of systems for telecommunications and space sectors.

3.0 DEVELOPMENTS

Over the last three decades, the space programme has taken important strides in meeting its objective. Two major operational space systems have been established - the Indian National Satellite (INSAT) for telecommunication, television broadcasting and metrological services and Indian Remote Sensing Satellite (IRS) system for resources monitoring and management.

Two launch vehicles, the Polar Satellite Launch Vehicle (PSLV) primarily for launching remote sensing satellites into polar orbits and the Geosynchronous Satellite Launch Vehicle (GSLV) for launching communication and metrological satellites into 36000 km high Geosynchronous Transfer Orbit (GTO) have been operationalised. Space application programmes with participation of user agencies have enabled the benefits of space programme to reach the grassroots level of society. Research in space science has contributed towards increased knowledge and understanding of several scientific phenomena. The capabilities built under space programme are used for commercial gains through international marketing of space hardware and services.

4.0 TECHNOLOGIES USED

4.1 The Indian National Satellite System

The Indian National Satellite (INSAT) system is one of the largest domestic communication satellite systems in the Asia-Pacific region. In the 1980s, it initiated a major revolution in India's communications sector and sustained the same later.

The satellites of INSAT system, which are in service today, are INSAT-2E, INSAT-3A, INSAT-3B, INSAT-3C, INSAT-3E, KALPANA-1, GSAT-2, EDUSAT and INSAT-4A that was launched recently. The system provides a total of about 175 transponders in the C, Extended C and Ku-bands. Being a multipurpose satellite system, INSAT provides services to telecommunications, television broadcasting, weather forecasting, disaster warning and Search and Rescue fields. The INSAT system serves many important sectors of the Indian economy. Foremost amongst them is Telecommunications sector wherein INSAT is providing Mobile Satellite Service besides providing VSAT services. Today, more than 25,000 Very Small Aperture Terminals (VSATs) are in operation.

Similarly, Television broadcasting and redistribution have been immensely benefited by INSAT. Thanks to INSAT, more than 900 million people in India have access to TV through about 1400 terrestrial rebroadcast transmitters. In addition to this, social development through exclusive channels for training and developmental education has become possible through INSAT. And, a Telemedicine network to take super speciality medical services to the remote and rural population has become a reality. The network now covers 152 hospitals-120 remote rural hospitals and 32 super speciality hospitals in major cities. The launch of EDUSAT, India's first thematic satellite dedicated exclusively for educational services, has provided further fillip to the educational services offered by the INSAT system INSAT system is also providing meteorological services through Very High Resolution Radiometer (VHRR) 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 operationalised. For this, 350 receivers have been installed along the east and west coasts of India.

4.2 Indian Remote Sensing Satellite System and its importance

India has the largest constellation of Remote Sensing Satellites, which are providing services both at the national and global levels. From the Indian Remote Sensing (IRS) Satellites, data is available in a variety of spatial resolutions starting from 360 metres and highest resolution being 2.5 metres. Besides, the state-of-the-art cameras of IRS spacecraft take the pictures of the Earth in several spectral bands. In future, ISRO intends to launch IRS spacecraft with better spatial resolution and capable of imaging day and night. The satellites of IRS system which are in service today are IRS-1C, IRS-ID, IRS-P3, OCEANSAT-1, Technology Experimental Satellite (TES). RESOURCESAT-1, and the recently launched CARTOSAT-1 are capable of taking stereo pictures. The upcoming Remote Sensing Satellite are Cartosat-2, RISAT (Radar Imaging Satellite) and Oceansat-2.

Imagery sent by IRS spacecraft is being put to a variety of uses in India with agricultural crop acreage and yield estimation being one of the most important uses. Besides, such imagery is being used for ground and surface water harvesting, monitoring of reservoirs and irrigation command areas to optimise water use. Forest survey and management and wasteland identification and recovery are other allied uses. This apart, IRS imagery is also used for mineral prospecting and forecasting of potential fishing zones.

With regard to applications in planning and management, IRS data is being used for urban planning, flood prone area identification and the consequent suggestions for mitigation measure. Based on this experience, the concept of Integrated Mission for Sustainable Development has been evolved wherein the spacecraft image data is integrated with the socio-economic data obtained from conventional sources to achieve sustainable development.

4.3 Satellite Launch Vehicles Programme of India

After successfully testing the first indigenous launch vehicle SLV-3 in 1980, ISRO built the next generation Augmented Satellite Launch Vehicle (ASLV). ISRO's Launch Vehicle Programme had a giant leap with the successful launch of IRS-P2 spacecraft onboard the Polar Satellite Launch Vehicle (PSLV) in October 1994. On 18 April 2001, India successfully launched its Geosynchronous Satellite Launch Vehicle (GSLV) Technology. A breakthrough was achieved during the year in Supersonic Combustion Ramjet (SCRAMJET) which was employed in Air-Breathing engine. This is an important element in the launch vehicle technology development. Concepts for reusable launch vehicle are also being studied.

4.4 P.S.L.V.

The four stage PSLV is capable of launching upto 1,600 kg satellites into an 620 km polar orbit. It has provision to launch payloads from 100 kg micro-satellites or mini or small satellites in different combinations. It can also launch one ton class payloads into Geosynchronous Transfer Orbit (GTO). So far, it has performed twenty missions with nineteen consecutive successes.

Latest success of PSLV:

PSLV-C 19 has successfully placed the RISAT-1 (Radar Imaging Satellite) of 1858 Kg in the 480 Km Polar orbit on 26 April, 2012.
On 12 October, 2011 PSLV-V 18 placed Megha - Tropiques, SRMSAT, Jugnu, VESALSAT Sattellites.
On 15 July, 2011 PSLV-C 17 placed GSAT-12 (Communication Satellite) in Geo-stationary orbit of 36,000 Km.

4.5 G.S.L.V.

The GSLV was successful on its very first test flight. After its successful second flight in May 2003, it was commissioned. This was followed by the success of its third flight in September 2004. The GSLV is capable of launching 2,000 kg class satellites into Geosynchronous Transfer Orbit (GTO). The development of Indigenous cryogenic stage to be used as the third stage of GSLV made further progress. The cryogenic engine which forms part of this stage, has already been successfully qualified. GSLV-Mk-III, a new version of GSLV and capable of launching spacecraft weighing upto 4 tonnes to GTO is under development.

5.0 Launch Infrastructure

An elaborate launch infrastructure exists at the Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota Island on the East Coast of India which is about 100 km from Chennai. Sriharikota is located at 13° North latitude. From here, satellites can be launched into a variety of orbital inclinations starting from 18° and extending upto 99° Full-fledged facilities for satellite integration, assembly and launch exist there. Sriharikota also houses a Telemetry, Tracking and Command network for tracking satellites and monitoring them. The newly built Second Launch Pad at SPSC SHAR as a redundancy to the existing launch pad, and to cater to the requirement of GSLV-Mk III as well as other future launch vehicles, was commissioned in May 2005 with the successful launch of PSLV-C6.

5.1 CartoSat-1

The satellite primarily intended for advanced Mapping applications. It was launched in May 2005.

Payload: Two panchromatic cameras with a spatial resolution of 2.5 meter and a swath of 30 km each.

New Technologies Used: Improved version of Star sensor, bus interface connecting control system, satellite positioning system and data handling.

5.2 Cartosat-2

It is advanced remote sensing satellite with single panchromatic camera capable of providing scene-specific spot imageries of cartographic applications. The camera with one-meter spatial resolution and swath of 10 km.

New Technologies: Two mirror on single axis camera, Carbon Fabric reinforced Plastic based electro optic structure, advanced solid state recorder, high torque reaction wheels, lightweight, large size mirrors. It was launched in 2007.

5.3 Radar Imaging Satellite (RISAT)

RISAT with night and day imaging capability as well as imaging under cloudy conditions will be important system to complement band of electro-optical sensors on board IRS System.

IRSAT will have multi-mode, multi-polarisation, agile synthetic Aperature Radar (SAR) operating in C-band and providing 3.50 meters spatial resolution. It will incorporate algorithms and data products to serve the user community.

5.4 OCEANSAT-2

It is envisaged for providing continuity to ocean sat-1. It will carry OCM and a Ku-band Pencil Beam scatterometer, 8-band multi-spectral camera. The scatterometer is a microwave radar for measuring ocean surface wind velocity. It will be launched in PSS orbit of 720 km altitude by PSLV.

5.5 TWSAT

The 90-kg TWSAT is a remote sensing micro-satellite proposed for third world countries. The payload will be a 2-band CCD Camera with single optics and beam splitter. The 50 user terminals, which can receive payload data are to be installed in Indian Universities and selected Third World Countries.

6.0 Scientific Missions

India has a vibrant space science programme covering astronomy, astrophysics, planetary and earth sciences. There activities are mainly carried out at Physical Research Laboratory (PRL), Ahemdabad, Space Physics Laboratory (SPL), Trivandrum, ISRO Satellite Centre, Bangalore. DOS has set up ground based facilities like Udaipur Solar observatory, Mesosphere-Stratosphere- Troposphere. Radar etc. Balloons, Sounding rockets. DOS also participates in international scientific campaigns like MONEX, IGBP, STEP and INDOEX.

6.1 Chandrayan I

Chandrayaan-1, India's first mission to Moon, was launched successfully on October 22, 2008 from SDSC SHAR, Sriharikota. The spacecraft was orbiting around the Moon at a height of 100 km from the lunar surface for chemical, mineralogical and photo-geologic mapping of the Moon. The spacecraft carries 11 scientific instruments built in India, USA, UK, Germany, Sweden and Bulgaria.

After the successful completion of all the major mission objectives, the orbit has been raised to 200 km during May 2009.

Scientific Objectives

High resolution remote sensing of the, moon in the visible, near infrared, low energy x--ray and high-energy x-ray regions for preparing 3-D atlas of regions of scientific interest.
Chemical mapping of entire lunar surface for elements such as Magnesium, Aluminium, Iron, Titanium, and Uranium. PSLV has launched the spacecraft into GTO.

Pay Loads

Terrain Mapping Camera with stereo imaging facility with panchromatic band with 5 m spatial resolution and 20 km swath
Hyper-spectral imager with spectral resolution of 15 nm
Lunar Ranging Instrument with vertical resolution of 5 m
Low energy x-ray spectrometer
High energy x-ray spectrometer

6.2 India's MARS orbiter mission (MANGALYAAN)

One of the main objectives of the first Indian mission to Mars is to develop the technologies required for design, planning, management and operations of an interplanetary mission. Following are the major objectives of the mission:

6.2.1 Technological Objectives

Design and realisation of a Mars orbiter with a capability to survive and perform Earth bound manoeuvres, cruise phase of 300 days.
Mars orbit insertion / capture, and on-orbit phase around Mars.
Deep space communication, navigation, mission planning and management. Incorporate autonomous features to handle contingency situations.

6.2.2 Scientific Objectives

Exploration of Mars surface features, morphology, mineralogy and
Martian atmosphere by indigenous scientific instruments.

Introduction

Total Weight (kg)1,350

Science Payload Weight (kg)14.49

Fuel Load (kg)850

Launch DateNovember 5, 2013

Trans Mars InjectionDecember 1, 2013

Planned Mars OrbitPeriapsis: 365-km, Apoapsis: 80,000 km, Orbital Period: Approx 77-hr

ISRO launched the 1,350 kg Mars Orbiter Mission Manglayaan from Sriharikota using PSLV-C25, an XL variant of the launcher, on November 5, 2013 at 14:38 hrs to avail of the November 2013 launch window for the planet. The launch was earlier scheduled for October 28, 2013, but was postponed to accommodate the delay in the arrival in South Pacific, due to bad weather, of one of the two SCI ships to be used for tracking the launch of the spacecraft.

ISRO is aiming to send the spacecraft hurtling on a Mars intercept trajectory from earth orbit at 0.42 hours on December 1. The Mars orbiter will be placed in an orbit of 372 x 80,000 km around Mars and will have a provision to carry 14.49 kg of scientific payload on- board. ISRO initially planned to use the GSLV to launch a 500 kg Mars orbiter with 25 kg scientific payload, but scaled down its plans because of two back to back failures of the launcher in 2010.

The GOI sanctioned seed money of Rs 10 crore in August 2009 to carry out studies on suitable experiments for the mission. The budget for FY 2012-13 allocated Rs. 125 crore for the mission during the financial year. The union cabinet cleared the project on Friday, August 3, 2012.

Mars Orbiter Team: In October 2012, ISRO announced Dr M Annadurai as program director of the Mars Orbiter Mission. SK Shivkumar will oversee design and development of the Orbiter.

Annadurai was earlier project director of Chandrayaan 1. Shivkumar, who played a key role in realizing the ground segment for Chandrayaan 1, is the director of Isro Satellite Center in Bengaluru, which will be t he lead center for the design, development, fabrication and testing of the Mars Orbiter Mission's payloads and satellites. S. Arunan is the Mars mission Project Director.

7.0 IMPORTANT TERMINOLOGIES

7.1 GlONASS (Global Navigation Satellite System)

The radio satellite navigation system the Russian counterpart to the United States GPS and Europe's Galileo. It is operated for Russian Government by Russian Space Forces.

Like GPS, the complete nominal GLONASS consists of 24 satellites. 21 operating and three on-orbit 'spares' placed in three orbital planes. GLOSNASS constellation orbits the Earth at an altitude of 19,100 km. Slightly lower than GPS.

The first three test satellites were placed in orbit in October 1982. The system was announced operational on September 1993, but constellation was completed by December 1995.

Due to the economic situation in Russia there were only 8 satellites in operation in April 2002, rendering it almost useless as a navigation aid. Since the economic situation in Russia has improved, 11 satellites were in operation by March 2004. An advanced GLOSSNASS satellite GLOSSNASS-M, with an operational lifetime of 7 years, has been developed. A 3-satellite block was launched in December 2004.

A further improved GLOSSNASS-K with reduced weight and increased operational lifetime of 10-12 years.

7.2 GALILEO

GALILEO is satellite Navigation System, a joint initiative of European Commission and European-Space Agency (ESA) agreed on March 2002, to introduce their own alternative to GPS. At a cost of about $ 2.5 billion, the required satellites were launched between 2006 and 2008, and the system is working, under civilian control from 2008. The first satellite was launched on December 28th 2005. The Galileo is compatible with next generation GPS System that became operational in 2012. The receivers combine signals from 30 Galileo and 28 GPS Satellites.

Thirty new satellites in Medium Earth Orbit have been placed at an altitude of 23,222 km.

8.0 ISRO's international cooperation in the space technology

From the days of its inception, ISRO has had a very good record of international cooperation. It has Memoranda of Understanding/Agreements with 26 countries/space agencies. A UN sponsored Centre for Space Science and Technology Education in Asia and the Pacific (CSSTE-AP) set up in India has trained more than 400 personnel of the Asia-pacific region. During the year, CSSTE-AP completed 10 years. In addition, ISRO provides training in space applications to personnel of developing countries through its Sharing of Experience in Space (SHARES) programme.

ISRO has launched scientific payloads of other space agencies like Modular Opto-electronic Scanner of DLR, Germany that was flown on IRS-P3 spacecraft and the data is being shared by scientists of DLR, India and the US. It has a cooperative agreement with NASAOAA for the reception of meteorological data from INSAT spacecraft by those agencies.

Megha-Tropiques is a joint satellite mission of ISRO and French Space Agency CNES for atmospheric studies. The satellite will be built and launched by ISRO and CNES will develop two of the payloads and the third payload jointly with ISRO. At the same time, scientific instruments developed in the United States, Germany, Sweden, UK and Bulgaria were launched on board India's Chadrayaan-1 spacecraft. This apart, an Italian scientific instrument will be included onboard India's OCEANSAT-2 satellite. Instruments for astronomical observation jointly developed with Israel and Canada will be flown onboard India's GSAT-4 and RISAT satellites respectively. And, an Indian scientific instrument to study solar physics and solar-terrestrial sciences will be flown onboard Russia's CORONAS-PHOTON satellite.

India has also set up three local User Terminals and a Mission Control Centre for the international COSPAS / SARSAT programme for providing distress alert and position location service. A search and Rescue Transponder is included in INSAT -3A spacecraft. India is a signatory to the International Charter on Disaster Management and is providing remote sensing data for the same.

9.0 SPACE TECHNOLOGY IN INDIA - LATEST DEVELOPMENTS

9.1 Budgetary Allocation

In the Budget for 2016-17 an amount of Rs 7509 crores is earmarked for DoS which is similar to the agency's funding over last year. In 2015-16, although the Department of Space was initially alloted Rs 7388 crore, that allocation was later revised to Rs 6959 crores.

The space department has taken several strides recently, launching the country's first inter-planetary project, the Mars Orbiter Mission, and the Geosynchronous Satellite Launch Vehicle (GSLV-D5).

Prime Minister Modi has said that the successful launch of the foreign satellites was a "global endorsement" of India's space capabilities developed by "our brilliant scientists".Noting that India had the potential to be a "large service provider" in this area, the Prime Minister said that efforts must be made to construct new infrastructure and upgrade to launching heavier satellites.

9.2 ISRO's major achievements

Recent years witnessed landmark achievements in the Indian Space programme with the launch of India's first interplanetary Mars Orbiter Mission and successful flight testing of indigenous Cryogenic Upper Stage onboard GSLV-D5. Besides this, launch of IRNSS-System - the first Indian Regional Navigation Satellite System; launch of GSAT-7 - a communication satellite under the contract with Antrix Corporation; and the launch of INSAT-3D - an advanced weather satellite, were also achieved during the year.

Mars Orbiter Mission, which is India's first interplanetary spacecraft mission, was successfully launched by PSLV-C25 into an elliptical earth parking orbit on November 05, 2013. It was the twenty fifth launch of PSLV as well as its twenty fourth successively successful mission. Trans Mars Injection manoeuvre was successfully carried out on December 01, 2013 setting the voyage of the spacecraft towards Mars, escaping the earth's sphere of influence. The spacecraft was inserted into Mars Orbit on September 24, 2014 as planned. With this India became the first nation in the world to carry out a Mission to Mars successfully in the first attempt.
GSLV-D5, with indigenous Cryogenic Upper Stage, launched GSAT-14 Communications spacecraft into Geosynchronous Transfer Orbit (GTO) very precisely on January 05, 2014. With this, India has joined the exclusive club of selected five nations as sixth member, having the capability to launch satellites to GTO.
IRNSS-1A, the first of the 7 satellites of the Indian Regional Navigation Satellite System (IRNSS) Constellation, was successfully launched on board PSLV-C22 on July 01, 2013 into a sub Geosynchronous Transfer Orbit (sub GTO). IRNSS constellation will enable introduction of satellite based position, timing and velocity services to a spectrum of users in the country and to the neighboring regions.
GSAT-7, a multi-band communication satellite realised under the contract with Antrix Corporation, was successfully launched on August 30, 2013 by the Ariane-5 launch vehicle from Kourou, French Guiana.
INSAT- 3D was launched on July 26, 2013 onboard Ariane-5 from Kourou, French Guiana and is an advanced weather satellite configured with improved imaging system and Atmospheric Sounder. INSAT-3D also carries a Data Relay Transponder and a Satellite Aided Search and Rescue Transponder (SAS&R)
ASTROSAT has been launched as an observatory in space in September 2015.

(Taken from ISRO's annual report)

10.0 ISRO SATELLITES

There are various types of satellites developed by ISRO over the years, as seen in the table earlier in this lecture.

Communication Satellites : Supports telecommunication, television broadcasting, satellite news gathering, societal applications, weather forecasting, disaster warning and Search and Rescue operation services.
Earth Observation Satellites : The largest civilian remote sensing satellite constellation in the world - thematic series of satellites supporting multitude of applications in the areas of land and water resources; cartography; and ocean & atmosphere.
Scientific Spacecraft : Spacecraft for research in areas like astronomy, astrophysics, planetary and earth sciences, atmospheric sciences and theoretical physics.
Navigation Satellites : Satellites for navigation services to meet the emerging demands of the Civil Aviation requirements and to meet the user requirements of the positioning, navigation and timing based on the independent satellite navigation system.
Experimental Satellites : A host of small satellites mainly for the experimental purposes. These experiments include Remote Sensing, Atmospheric Studies, Payload Development, Orbit Controls, recovery technology etc.
Small Satelites : Sub 500 kg class satellites - a platform for stand-alone payloads for earth imaging and science missions within a quick turn around time.
Student Satellites : ISRO's Student Satellite programme is envisaged to encourage various Universities and Institutions for the development of Nano/Pico Satellites.

10.1 Communication Satellites

The Indian National Satellite (INSAT) system is one of the largest domestic communication satellite systems in Asia-Pacific region with nine operational communication satellites placed in Geo-stationary orbit. Established in 1983 with commissioning of INSAT-1B, it initiated a major revolution in India’s communications sector and sustained the same later. GSAT-17 joins the constellation of INSAT System consisting 15 operational satellites, namely - INSAT-3A, 3C, 4A, 4B, 4CR and GSAT-6, 7, 8, 9, 10, 12, 14, 15, 16 and 18.

The INSAT system with more than 200 transponders in the C, Extended C and Ku-bands provides services to telecommunications, television broadcasting, satellite newsgathering, societal applications, weather forecasting, disaster warning and Search and Rescue operations.

full table here - http://civils.pteducation.com/p/spacetechnology.html

10.2 Earth Observation Satellites

Starting with IRS-1A in 1988, ISRO has launched many operational remote sensing satellites. Today, India has one of the largest constellations of remote sensing satellites in operation. Currently, *thirteen* operational satellites are in Sun-synchronous orbit – RESOURCESAT-1, 2, 2A CARTOSAT-1, 2, 2A, 2B, RISAT-1 and 2, OCEANSAT-2, Megha-Tropiques, SARAL and SCATSAT-1, and *four* in Geostationary orbit- INSAT-3D, Kalpana & INSAT 3A, INSAT -3DR. Varieties of instruments have been flown onboard these satellites to provide necessary data in a diversified spatial, spectral and temporal resolutions to cater to different user requirements in the country and for global usage. The data from these satellites are used for several applications covering agriculture, water resources, urban planning, rural development, mineral prospecting, environment, forestry, ocean resources and disaster management.

full table here - http://civils.pteducation.com/p/spacetechnology.html

10.3 Space Science & Exploration

Indian space programme encompasses research in areas like astronomy, astrophysics, planetary and earth sciences, atmospheric sciences and theoretical physics. Balloons, sounding rockets, space platforms and ground-based facilities support these research efforts. A series of sounding rockets are available for atmospheric experiments. Several scientific instruments have been flown on satellites especially to direct celestial X-ray and gamma-ray bursts.

AstroSat - AstroSat is the first dedicated Indian astronomy mission aimed at studying celestial sources in X-ray, optical and UV spectral bands simultaneously. The payloads cover the energy bands of Ultraviolet (Near and Far), limited optical and X-ray regime (0.3 keV to 100keV). One of the unique features of AstroSat mission is that it enables the simultaneous multi-wavelength observations of various astronomical objects with a single satellite. AstroSat with a lift-off mass of 1515 kg was launched on September 28, 2015 into a 650 km orbit inclined at an angle of 6 deg to the equator by PSLV-C30 from Satish Dhawan Space Centre, Sriharikota. The minimum useful life of the AstroSat mission is expected to be 5 years.
Mars Orbiter Mission - Mars Orbiter Mission is ISRO’s first interplanetary mission to planet Mars with an orbiter craft designed to orbit Mars in an elliptical orbit of 372 km by 80,000 km. Mars Orbiter mission can be termed as a challenging technological mission and a science mission considering the critical mission operations and stringent requirements on propulsion, communications and other bus systems of the spacecraft. The primary driving technological objective of the mission is to design and realize a spacecraft with a capability to perform Earth Bound Manoeuvre (EBM), Martian Transfer Trajectory (MTT) and Mars Orbit Insertion (MOI) phases and the related deep space mission planning and communication management at a distance of nearly 400 million Km. Autonomous fault detection and recovery also becomes vital for the mission.
Chandrayaan-1 - Chandrayaan-1, India's first mission to Moon, was launched successfully on October 22, 2008 from SDSC SHAR, Sriharikota. The spacecraft was orbiting around the Moon at a height of 100 km from the lunar surface for chemical, mineralogical and photo-geologic mapping of the Moon. The spacecraft carried 11 scientific instruments built in India, USA, UK, Germany, Sweden and Bulgaria.
Chandrayaan-2 - Chandrayaan-2 will be an advanced version of the previous Chandrayaan-1 mission to Moon.Chandrayaan-2 is configured as a two module system comprising of an Orbiter Craft module (OC) and a Lander Craft module (LC) carrying the Rover developed by ISRO.

full table here - http://civils.pteducation.com/p/spacetechnology.html

10.4 Satellite Navigation

Satellite Navigation service is an emerging satellite based system with commercial and strategic applications. ISRO is committed to provide the satellite based Navigation services to meet the emerging demands of the Civil Aviation requirements and to meet the user requirements of the positioning, navigation and timing based on the independent satellite navigation system. To meet the Civil Aviation requirements, ISRO is working jointly with Airport Authority of India (AAI) in establishing the GPS Aided Geo Augmented Navigation (GAGAN) system. To meet the user requirements of the positioning, navigation and timing services based on the indigenous system, ISRO is establishing a regional satellite navigation system called Indian Regional Navigation Satellite System (IRNSS).

GPS Aided GEO Augmented Navigation (GAGAN) : This is a Satellite Based Augmentation System (SBAS) implemented jointly with Airport Authority of India (AAI). The main objectives of GAGAN are to provide Satellite-based Navigation services with accuracy and integrity required for civil aviation applications and to provide better Air Traffic Management over Indian Airspace. The system will be interoperable with other international SBAS systems and provide seamless navigation across regional boundaries. The GAGAN Signal-In-Space (SIS) is available through GSAT-8 and GSAT-10.
Indian Regional Navigation Satellite System (IRNSS) : NavIC - This is an independent Indian Satellite based positioning system for critical National applications. The main objective is to provide Reliable Position, Navigation and Timing services over India and its neighbourhood, to provide fairly good accuracy to the user. The IRNSS will provide basically two types of services

Standard Positioning Service (SPS) Restricted Service (RS) : To date, ISRO has built a total of nine satellites in the IRNSS series; of which eight are currently in orbit Three of these satellites are in geostationary orbit (GEO) while the remaining in geosynchronous orbits (GSO) that maintain an inclination of 29° to the equatorial plane. The IRNSS constellation was named as “NavIC” (Navigation with Indian Constellation) by the Honourable Prime Minister, Mr. Narendra Modi and dedicated to the nation on the occasion of the successful launch of the IRNSS-1G satellite. The eight operational satellites in the IRNSS series, namely IRNSS-1A, 1B, 1C, 1D, 1E, 1F, 1G and 1I were launched on Jul 02, 2013; Apr 04, 2014; Oct 16, 2014; Mar 28, 2015; Jan 20, 2016; Mar 10, 2016, Apr 28, 2016; and Apr 12, 2018 respectively. The PSLV-39 / IRNSS-1H being unsuccessful; the satellite could not reach orbit.

full table here - http://civils.pteducation.com/p/spacetechnology.html

10.5 Experimental Satellites

ISRO has launched many small satellites mainly for the experimental purposes. This experiment include Remote Sensing, Atmospheric Studies, Payload Development, Orbit Controls, recovery technology etc.

10.6 Small Satellites

The small satellite project is envisaged to provide platform for stand-alone payloads for earth imaging and science missions within a quick turn around time. For making the versatile platform for different kinds of payloads, two kinds of buses have been configured and developed.

Indian Mini Satellite -1 (IMS-1)

IMS-1 bus has been developed as a versatile bus of 100 kg class which includes a payload capability of around 30 kg. The bus has been developed using various miniaturization techniques. The first mission of the IMS-1 series was launched successfully on April 28th 2008 as a co-passenger along with Cartosat 2A. Youthsat is second mission in this series and was launched successfully along with Resourcesat 2 on 20th April 2011.

Indian Mini Satellite -2 (IMS-2) Bus

IMS-2 Bus is evolved as a standard bus of 400 kg class which includes a payload capability of around 200kg. IMS-2 development is an important milestone as it is envisaged to be a work horse for different types of remote sensing applications. The first mission of IMS-2 is SARAL. SARAL is a co-operative mission between ISRO and CNES with payloads from CNES and spacecraft bus from ISRO.

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ISRO - Indigenous Cryogenic Engine and Stage

A Cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse (a measure of the efficiency) achievable with cryogenic propellants (liquid Hydrogen and liquid Oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage. But cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and associated thermal and structural problems. Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C. The propellants, at these low temperatures are to be pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of cryo fluids and related safety aspects. ISRO's Cryogenic Upper Stage Project (CUSP) envisaged the design and development of the indigenous Cryogenic Upper Stage to replace the stage procured from Russia and used in GSLV flights. The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum. During the flight, CUS fires for a nominal duration of 720 seconds. Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbopump to ensure a high flow rate of propellants into the combustion chamber. Thrust control and mixture ratio control are achieved by two independent regulators. Two gimballed steering engines provide for control of the stage during its thrusting phase.