Satellite programme

Science Affairs Space

Satellite programme

In the past three-and-a-half decades, since the first rocket took off from Thumba in 1963, India has come a long way in making the space programme self-reliant. It is now able to not only design and build satellites like INSAT and IRS but also to launch them using indigenously designed and built rockets. PSLV has already become operational. Now, with the GSLV off the ground, Indian space programme is set to meet the growing needs of the country in the field of space technology in a self-reliant manner.

Aryabhatta

Aryabhatta, the 360 kg first Indian Satellite, was launched on April 19, 1975 from USSR into the orbit with the help of a Soviet Intercosmos rocket.

Bhaskara

Bhaskara - I, India’s first experimental earth observation satellite, was to conduct earth observation experiments, to collect, process, analyze and disseminate data of relevance to hydrology, forestry and geology using two television wave lengths; and study ocean-state liquid water content in the atmosphere.

APPLE (Ariane Passenger Payload Experiment)

APPLE was launched by the European Space Agency’s (ESA) Ariane launcher on June 19, 1981 from Kourou, French Guyana.

Rohini Satellites (RS-1) Series

The first RS-1 satellite was injected into an elliptical orbit by the second experimental flight of SLV-3 on July 18, 1980. The Second RS-1 satellite (RS-D1) was flown on the first developmental flight of the SLV-3 (SLV-3 D-1) on May 30, 1981.

Stretched Rohini Satellite Series (SROSS)

The SROSS Project envisages the development of spacecraft of 150 kg. Class for launch on the Augmented Satellite Launch Vehicle (ASLV) and in orbit operations of spacecraft and experimental payloads pertaining the scientific technological and remote sensing missions.

INSAT System

The Indian National Satellite System (INSAT) is a multipurpose operational satellite system for domestic telecommunications; meteorological observations and data relay nationwide direct satellite television broadcasting and radio, television programme distribution. The System is a joint venture of Department of Space (DOS), Department of Telecommunications (DOT), India Meteorological Department (IMD) and Prasar Bharti .

Established in 1983 with commissioning of INSAT-1B, it initiated a major revolution in India’s communications sector and sustained the same later. Currently operational communication satellites are INSAT-3A, INSAT-3C, INSAT-3E, INSAT-4A, INSAT-4B, INSAT-4CR, GSAT-8, GSAT-10 and GSAT-12.

New Applications

To promote an effective interactive educational system through satellites.
The success of the ISRO-UGC experiment which enabled students in a number of universities to interact, with experts
An innovative interactive training programme for farmers of Bhiwani district of Haryana, in August 1992, carried out jointly with Haryana Agricultural University, Hissar.
Several interactive programmes for education in rural development with programmes on development of women and children in rural areas and watershed development.
Programmes on Panchayat Raj for elected women members
Geo stationary satellites provide different services:Telecommunication, Tele Broadcasting, Radio Broadcasting, Data Relay, Weather Forecasting, Disaster Warming, Search and Rescue

India's Advanced Communication Satellite GSAT-7 Launched

India's advanced multi-band communication satellite, GSAT-7, was successfully launched on August 30, 2013 by the Ariane-5 launch vehicle of Arianespace from Kourou, French Guiana. Ariane- into the intended Geosynchronous Transfer Orbit (GTO)
ISRO's Master Control Facility (MCF) at Hassan in Karnataka started acquiring the signals five minutes prior to the separation of GSAT-7 from Ariane-5 launch vehicle.
The present orbit of the satellite will be raised to Geostationary Orbit of about 36,000 km altitude through three orbit raising manoeuvres by firing of GSAT-7's Liquid Apogee Motor (LAM).

Types of Orbits in which Satellites are Placed:

Before designing a satellite, scientists chose an orbit that is appropriate to its function as a satellite. The speed of the satellite moving in the Orbit, the area which the satellite can observe, and the frequency with which the satellite passes over the same portions of the Earth are all important factors to consider when choosing an Orbit.

There are different basis for the classification of Satellites which includes Centric Classification (Heliocentric, Geocentric etc); Altitude Classification (Low Earth Orbit, Medium Earth Orbit); Synchronicity Classification (Sun Synchronous, Geo Synchronous). The following table gives a gist of different types of orbits:

Table

Geosynchronous Orbits:	These orbits placed at an altitude of nearly 36,000 km are synchronised with Earth's Rotation, but the Orbit is tilted with respect to the plane of equator. The synchronisation of rotation and orbital period means that for an observer on the surface of the Earth, an object in geosynchronous orbit returns to exactly the same position in the sky after a period of one sidereal day They are primarily used for communication, weather monitoring and surveillance
Geostationary Orbits	These are also geosynchronous orbit, but lies in equatorial plane. It has an orbital period equal to the Earth's Rotational Period and thus appears motionless, at a fixed point in the sky to the ground observer. There is only one geostationary Orbit Speed at which a satellite orbits the Earth coincides with the speed that the Earth rotates and at the same latitude, however, this does not mean that the satellite and the Earth are traveling at the same speed, but rather that the satellite is traveling fast enough so that its orbit matches the Earth’s rotation.
Polar Orbit:	This Orbit usually has an inclination of 90 degrees to the equator On every pass around the earth, it passes over both the North and South Poles . This allows the satellite to see virtually every part of the Earth as the Earth rotates underneath it. Such orbits are suitable for surveillance and mapping operations
Sun Synchronous Orbit	It is a subset of polar orbit and travels from North to South Poles. It lies in a plane that maintains a fixed angle with respect to Earth-Sun direction i.e. the angle between the orbital plane and the earth sun line remains constant throughout the year. It is most useful for satellites concerned with imaging and remote sensing
Orbits based on Altitude	Low Earth Orbits: 180-2000km Medium Earth Orbit: 2000-35,780km Higher Earth Orbit: above 35,780km