Space Technology, Remote Sensing & Agni

Part 2 · Use of satellite technology in improving the quality of common man's life

How Satellites Improve Everyday Life

Telephones and TV in remote areas, crop and flood mapping, distance education, telemedicine, maps and rural service centres.

The purpose

The prime objective of ISRO is to use space technology and its application to various national tasks.
With India's economic progress, its space program has become more visible and active as the country aims for greater self-reliance in space technology.

India uses its satellite communication network – one of the largest in the world – for applications such as land management, water resources management, natural disaster forecasting, radio networking, weather forecasting, meteorological imaging and computer communication.
The INSAT-2 satellites also provide telephone links to remote areas; data transmission for organisations such as the National Stock Exchange; mobile satellite service communications for private operators, railways, and road transport, and broadcast satellite services, used by India's state-owned television agency as well as commercial television channels.
Applied satellite technology helps in implementation of various socio-economical programs, e.g. identifying the crop loss due to disaster for Farmer relief.

Soft power

ISRO is also a tool for national image building and show casing India's soft power.

Foreign exchange

Earning foreign exchange for launching satellites for other countries: the revenue can be used for socio-economic development.

Part 3 · Military uses of space and the Agni missiles

Space for Defence, and the Agni Missile Family

Military satellites for the armed forces, spin-offs from rockets to missiles, and the Agni series of nuclear-capable ballistic missiles.

Military

Integrated Space Cell, under the Integrated Defence Staff headquarters of the Indian Ministry of Defence, has been set up to utilise more effectively the country's space-based assets for military purposes and to look into threats to these assets.
- The Integrated Space Cell envisages cooperation and coordination between the three services as well as civilian agencies dealing with space.
GSAT-7A, an advanced military communications satellite exclusively for the Indian Air Force and is similar to Indian Navy's GSAT-7.
- GSAT-7 provided the real-time input capabilities to Indian warships, submarines and maritime aircraft.
EMISAT, developed by DRDO under Project Kautilya and launched in 2019, is India's 1st Electronic Intelligence (ELINT) Satellite which will increase the situational awareness of the armed forces by providing the location and information of hostile radars placed at the borders.
India's satellites and satellite launch vehicles have had military spin-offs, e.g. Prithvi missile is not derived from the Indian space programme, the intermediate range Agni missile is drawn from the Indian space programme's SLV-3.
Recently satellite images helped knowing the Chinese position in Galwan valley.

Agni

The Agni missile is a family of medium to intercontinental range ballistic missiles developed by India, named after one of the five elements of nature. Agni missiles are long range, nuclear weapons capable surface to surface ballistic missile.

The first missile of the series, Agni-I was developed under the Integrated Guided Missile Development Program (IGMDP) and tested in 1989. After its success, Agni missile program was separated from the IGMDP upon realizing its strategic importance. It was designated as a special program in India's defence budget and provided adequate funds for subsequent development.

The Agni family

The family comprises the following:

Missile	Class	Range	Status
Agni-I	MRBM	700–1,200 km	Operational
Agni-II	MRBM	2,000–3,500 km	Operational
Agni-III	IRBM	3,000–5,000 km	Operational
Agni-IV	IRBM	3,500–4,000 km	Operational
Agni-V	ICBM	5,000–8,000 km	Operational
Agni-VI	ICBM	11,000–12,000 km	Under development

Agni-V and beyond

The latest version, Agni-V is a solid fueled intercontinental ballistic missile (ICBM) developed by Defence Research and Development Organisation (DRDO) of India. It will greatly expand India's reach to strike targets more than 5,500 km away. Coming version Agni-VII will be capable of being launched from submarines as well as from land, and will have a strike-range of 8,000–10,000 km.

Example: MRBM, IRBM and ICBM are range classes: medium-range (roughly 1,000–3,000 km), intermediate-range (3,000–5,500 km) and intercontinental (above 5,500 km). Agni-V's 5,000+ km places most of Asia within reach.

Part 4 · The achievements of ISRO and India's progress in satellite launching

What ISRO Has Achieved

From Aryabhata to Chandrayaan: communication, earth observation, astronomy, navigation, exploration and launch vehicles that carry 104 satellites at once.

The early milestones

ISRO built India's first satellite, Aryabhata, which was launched by the Soviet Union on 19 April 1975.
- In 1980, Rohini became the first satellite to be placed in orbit by an Indian-made launch vehicle, SLV-3.
ISRO subsequently developed two other rockets: the Polar Satellite Launch Vehicle (PSLV) for launching satellites into polar orbits and the Geosynchronous Satellite Launch Vehicle (GSLV).
ISRO has put into operation two major satellite systems: the Indian National Satellites (INSAT) series for communication services, and the Indian Remote Sensing Programme (IRS) satellites series for management of natural resources.

Satellite communication:

The first area was of satellite communication, with INSAT and GSAT as the backbones, to address the national needs for telecommunication, broadcasting and broadband infrastructure.
Gradually, bigger satellites have been built carrying a larger array of transponders. About 200 transponders on Indian satellites provide services linked to areas like telecommunication, telemedicine, television, disaster management etc.
GSAT-11, the heaviest satellite is part of ISRO's new family of high-throughput communication satellite (HTS) fleet that will drive the country's Internet Broadband from space to untouched areas. It is built to provide throughput data rate of 16 gbps.
GSAT 29 is a multi-beam, multiband communication satellite of India which will bridge the digital divide of users including those in Jammu & Kashmir and North Eastern regions of India.
The South Asia Satellite (GSAT-9) is a geosynchronous communications satellite by ISRO for the South Asian Association for Regional Cooperation (SAARC) region.
- For serving the needs of SAARC member nations, part of India's ‘neighbourhood first’ policy.

Part 5 · The advantages and disadvantages of launching multi-satellites in space

Many Satellites, One Rocket

India set records by launching ten and then 104 satellites at once; sharing a ride saves cost and time but adds weight, complexity and debris.

Multi-satellite launches

India became the first nation to launch ten satellites on one rocket. Later, it launched as many as 104 satellites in single launch.
Multiple satellites can be launched and deployed at once by a single launch vehicle. Large satellites are mounted directly above the last stage on an expendable launch vehicle. Similarly, multiple small satellites are also mounted above the last stage.

Advantages

The rapid deployment of a whole series of satellites
The lower cost to orbit per satellite.
No frequent launching of vehicle: less pollution.

Disadvantages

The mass of the additional structure
The additional orbit maneuvers to deploy the satellites
The added complexity of the separation
The additional test and integration of the entire payload.
Space Debris Production

Example: A multi-satellite launch is like a shared taxi: each passenger pays far less than for a private ride, but the driver must carry extra seats, plan more stops and drop everyone at the right place without bumping into each other.

Part 6 · The next exciting targets of ISRO

ISRO's Next Targets, and the Limits of Satellites

New and reusable launchers, a super-heavy rocket, human spaceflight, a space station and missions to the Moon, Venus and the Sun.

Future plans include development of

Unified Launch Vehicle

The core objective is to design a modular architecture that could eventually replace the PSLV, GSLV Mk I/II and GSLV Mk III with a single family of launchers.

Small Satellite Launch Vehicle

With payload capacity to deliver 500 kg to Low Earth orbit (500 km) or 300 kg to Sun synchronous orbit (500 km) for launching small satellites, with the capability to support multiple orbital drop-offs.

Reusable launch vehicle

Though initial scaled down prototype of launch vehicle has already been developed and tested successfully.
The development of final version of RLV is in progress. It is expected to take off vertically like a rocket, deploy a satellite in orbit, return to Earth, and land on a runway.

Future Super-heavy Lift Launch Vehicle

ISRO is conducting preliminary research for the development of a Super heavy-lift launch vehicle which is planned to have a lifting capacity of over 50–60 tonnes into an unspecified orbit.

Human spaceflight

The Indian Human Spaceflight Programme was initiated in 2007 by ISRO:
- To develop the technology needed to launch crewed orbital spacecrafts into low Earth orbit.
- The first crewed flight was planned with a spacecraft called Gaganyaan by 2022.
- If completed, India will become the fourth nation to conduct independent human spaceflight after the Soviet Union/Russia, United States and China.
- After conducting crewed spaceflights, the agency intends to start a space station programme and possibly a crewed lunar landing.
A space station.

Interplanetary and solar missions

Interplanetary probes, e.g. probes to Mars, Venus and near-Earth objects.
- Chandrayaan-3 is planned for moon in 2021.
- Shukrayaan-1 is planned for Venus in 2023.
A solar spacecraft mission: Aditya-L1 is a spacecraft mission to study the Sun.
- It has been designed and will be built in collaboration between the Indian Space Research Organisation (ISRO) and various Indian research institutes.
- It is planned to be launched by the end of 2020. It is India's first solar mission.

Issues with satellite communication

Design, development, investment and insurance of satellite requires higher cost.
Satellites are not easy to repair and maintain.
To reach the satellite from Earth, time can vary between 270 milliseconds and return again to 320 milliseconds. This propagation delay can cause an echo over telephone connections.
Some circumstances like weather or sunspots affect the satellite's signal and can cause interference and make proper operation of the satellite very difficult.
It requires to be monitored and controlled on regular periods so that it remains in the orbit, once it has been launched.
Fear of space weaponisation/satellite data hacking etc.

Part 7 · What is remote sensing? Its status in India

Remote Sensing and India's IRS Programme

Gathering information about the Earth without touching it, from India's 1970 helicopter experiment to the IRS, the world's largest civilian constellation.

Remote sensing

Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object. In current usage, the term “remote sensing” generally refers to the use of satellite or aircraft-based sensor technologies to detect and classify objects on Earth. It includes the surface and the atmosphere and oceans, based on propagated signals (e.g. electromagnetic radiation).

Active remote sensing

When a signal is emitted by a satellite or aircraft to the object and its reflection detected by the sensor.
RADAR and LiDAR are examples of active remote sensing where the time delay between emission and return is measured, establishing the location, speed and direction of an object.

Passive remote sensing

When the reflection of sunlight is detected by the sensor.
Examples of passive remote sensors include film photography, infrared, charge-coupled devices, and radiometers.

Some specific uses of remotely sensed images of the Earth

Forest fires

Large forest fires can be mapped from space, allowing rangers to see a much larger area than from the ground.

Weather and volcanoes

Tracking clouds to help predict the weather or watching erupting volcanoes, and help watching for dust storms.

Change over time

Tracking the growth of a city and changes in farmland or forests over several years or decades.

Ocean floor

Discovery and mapping of the rugged topography of the ocean floor (e.g., huge mountain ranges, deep canyons, and the “magnetic striping” on the ocean floor).

Planning

In the areas of urban sprawl, infrastructure planning and other large scale applications for mapping.

The status of remote sensing in India

India's remote sensing program was developed with the idea of applying space technologies for the benefit of human kind and the development of the country.
India demonstrated the ability of remote sensing for societal application by detecting coconut root-wilt disease from a helicopter mounted multispectral camera in 1970. This was followed by flying two experimental satellites, Bhaskara-1 in 1979 and Bhaskara-2 in 1981. These satellites carried optical and microwave payloads.
India's remote sensing programme under the Indian Space Research Organization (ISRO) started off in 1988 with the IRS-1A, the first of the series of indigenous state-of-art operating remote sensing satellites, which was successfully launched into a polar sun-synchronous orbit.
- Following the successful demonstration flights of Bhaskara-1 and Bhaskara-2 satellites, India began to develop the indigenous Indian Remote Sensing (IRS) satellite program to support the national economy in the areas of agriculture, water resources, forestry and ecology, geology, water sheds, marine fisheries and coastal management.
India also established the National Natural Resources Management System (NNRMS) providing operational remote sensing data services.
Data from the IRS satellites is received and disseminated by several countries all over the world.
The IRS system is the largest constellation of remote sensing satellites for civilian use in operation today in the world, with 11 operational satellites. All these are placed in polar Sun-synchronous orbit and provide data in a variety of spatial, spectral and temporal resolutions.
Various satellites are being launched by ISRO to enrich the remote sensing data.
- Cartosat-3: It is the third generation Earth observation satellite built by ISRO. It is one of the most advanced imaging satellites built by the organization so far. It includes Hyperspectral (Captures light from electromagnetic spectrum), Panchromatic (Captures all visible colors of light) and Multispectral (Captures light within specific ranges of the electromagnetic spectrum).
- RISAT-2BR1 is a synthetic-aperture radar (SAR) imaging satellite for reconnaissance built by Indian Space Research Organisation (ISRO). They provide all-weather surveillance using synthetic aperture radars (SAR).
- RESOURCESAT-2A
Future IRS launches are Resourcesat-2, Oceansat-3 etc.

Bhuvan

Data from IRS is available to its users through NRSC Data Centre and also through Bhuvan Geoportal of ISRO. Thus, India is seriously harnessing the remote sensing technology for enriching the data availability in diverse area which helps in evidence based decision making.

Exam preparation

BPSC Mains Previous Year Questions

Every question this page prepares you for, with the parts that answer it.

Q163rd BPSC · 2018

What progress India has made in the field of space satellite launching? What are the advantage and disadvantage of launching multi-satellites in space? How does the entry in this field help India to strengthen its economy?

Study:ISRO's Achievements Multi-Satellite Launches Satellites & Daily Life

Q260–62nd BPSC · 2018

How do you see achievements of Indian Space Research Organization (ISRO)? What are their next exciting targets?

Study:ISRO ISRO's Achievements Next Targets

Q348–52nd BPSC · 2007

Write an account on space research activities going on in India. How have such researches been helpful in development of the country?

Study:ISRO Satellites & Daily Life Military Uses & Agni ISRO's Achievements

Q443rd BPSC · 2001

How satellite technology can be used in improving the quality of common man's life?

Study:Satellites & Daily Life Next Targets

Q542nd BPSC · 1999

What is remote sensing? Describe the status of remote sensing in India.

Study:Remote Sensing

Q639th BPSC · 1993

Write short notes on: “Agni”.

Study:Military Uses & Agni

Quick revisionSatellites in daily life Quick revisionMilitary uses and the Agni family Quick revisionIndia's IRS programme

Space Technology & Remote SensingISRO, Satellites, Launchers & Agni

ISRO: Space for National Development