An object that revolves around a planet in a stable and consistent orbit is called a satellite. Satellites can be classified into two categories – natural and artificial.
All natural objects revolving around a planet are natural satellites. They are also called moons. Most moons are spherical, the ones that are not usually asteroids or meteors that were captured by the strong gravity of a planet. All planets except mercury and Venus in our solar system have moons. Earth has only one moon- whereas planets like Jupiter and Saturn have more than 60 moons.
Artificial satellites are man-made objects placed in an obit to rotate around a planet – usually the Earth. The world’s first artificial satellite launched was Sputnik-1 by Russia, Aryabhatta was the first satellite launched by India. These satellites are used in television and radio transmission, studying agriculture yield, locating mineral resources, weather forecasting, locate different places on earth.
The Indian Space Research Organisation (ISRO) is the space agency of the Government of India headquartered in the city of Bangalore. Its vision is to “harness space technology for national development while pursuing space science research and planetary exploration.”
Formed in 1969, ISRO superseded the erstwhile Indian National Committee for Space Research (INCOSPAR) established in 1962 by the Scientist Vikram Sarabhai. The establishment of ISRO thus institutionalized space activities in India. It is managed by the Department of Space, which reports to the Prime Minister of India. ISRO built India’s first satellite, Aryabhatta, which was launched by the Soviet Union on 19 April 1975.
It was named after the Indian astronomer Aryabhata. 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) for placing satellites into geostationary orbits.
These rockets have launched numerous communication satellites and earth observation satellites. Satellite navigation systems like GAGAN and IRNSS have been deployed. In January 2014, ISRO used an indigenous cryogenic engine in a GSLV-D5 launch of the GSAT-14.
ISRO sent a lunar orbiter, Chandrayan -1, on 22 October 2008 and a Mars orbiter, Mars Orbiter Mission, on 5 November 2013, which entered Mars orbit on 24 September 2014, making India the first nation to succeed on its first attempt to Mars, and ISRO the fourth space agency in the world as well as the first space agency in Asia to reach Mars orbit. On 18 June 2016 ISRO set a record with a launch of 20 satellites in a single payload.
On 15 February 2017, ISRO launched 104 satellites in a single rocket (PSLV-C37) and created a world record. ISRO launched its heaviest rocket, Geosynchronous Satellite Launch Vehicle Mark III (GSLV-Mk III), on 5 June 2017 and placed a communications satellite GSAT-19 in orbit. With this launch, ISRO became capable of launching 4 ton heavy satellites. ISRO launched Chandran 2 on July 22, 2019, Geosynchronous Satellite Launch Vehicle (GSLV-Mk III). It entered the Moon’s orbit on August 20, 2019 and its lander landed on the Moon on September 7.
Points to Remember
The field of study of the universe is called astronomy.
The universe consists of galaxies, planets, stars, meteorites, satellites and all other forms of matter and energy.
The half moon during the waxing period is called as first quarter and the half moon during the waning period is called as third quarter.
The word crescent refers to the phases where the moon is less than half illuminated. The word gibbous refers to phases where the moon is more than half illuminated.
The reversal of direction of planets is called as ‘retrograde motion’.
The geocentric theory followed by the ancient people proposed that the Earth is at the centre and the sun and other planets revolve around it.
The helio-centric theory states that the sun I at the centre and the planets revolve around it
Galilio gave the observational evidence to support the heliocentric theory
There are at least hundreds of billions of galaxies in the Universe.
A galaxy is a large collection of stars or cluster of stars and celestial bodies held together by gravitational attraction.
A constellation is a recognizable pattern of stars in the night sky when viewed from the Earth.
An object that revolves around a planet in a stable and consistent orbit is called a satellite.
The Indian Space Research Organization (ISRO) is the space agency of the Government of India headquartered in the city of Bangalore.