Artificial Satellites

Introduction:

A satellite is an object which has been placed into orbit byhuman endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon. Satellites are usually semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as space debris. A few space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Mars, Jupiter and Saturn.

Space Research:

Quite obviously when we learn about what a Satellite actually is, a question arises why do we need this. The answer is quite obvious, ever since man has come to his senses, ever since he has completed exploring the land from good old Galileo times till date, there is a curiosity to learn about the space. And to learn about space one has to go onto there, which is quite impossible, so man began to make satellites which would go to the place where needed and give the information that the man needs.

Satellites Sent:

The first artificial satellite, Sputnik 1, was launched by the Soviet Union in 1957. Since then, thousands of satellites have been launched into orbit around the Earth. These originate from more than 50 countries and have used the satellite launching capabilities of ten nations.

Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in theUnited States and ignited the so-called Space Race within the Cold War. Sputnik 2 was launched on November 3, 1957 and carried the first living passenger into orbit, a dog named Laika.

On January 31, 1958, Explorer 1 became the United States' first satellite to reach out to heavens.

Astérix, the first French satellite, was launched on November 26. Due to the relatively high altitude of its orbit, it is not expected to re-enter Earth's atmosphere for several centuries to come.

ISRO and Space Research

Aryabhatta was India's first satellite, named after the great Indian astronomer of the same name. It was launched with the help of Soviet Union on 19 April 1975 from Kapustin Yar but it was built by the Indian Space Research Organization (ISRO) to gain experience in building and operating a satellite in

space. Then on 07 Jun 1979, Bhaskara-I was sent into space and this first experimental remote sensing satellite, carried TV and microwave cameras.

Rohini is the name given to a series of satellites launched by theIndian Space Research Organisation. The Rohini series consisted of four satellites, all of which were launched by the Indian Satellite Launch Vehicle (SLV) and three of which made it successfully to orbit. Rohini RS-1 was launched on 18 July 1981. And then RS-1 D1 in 31 May 1981.

Kalpana-1 is the first dedicated meteorological satellite launched by Indian Space Research Organisation using Polar Satellite Launch Vehicle on 2002-09-12. This was the first satellite launched by the PSLV into the Geostationary orbit. 

Chandrayaan-1 was India's first unmanned lunar probe. It was launched by the Indian Space Research Organisation in October 2008, and operated until August 2009. It carries 11 scientific instruments built in India, USA, UK, Germany, Sweden and Bulgaria.

Future Planned at ISRO:

ISRO has declared that it has set a budget of around 2.8 Billion Rupees for Space Research

purposes in the next decade. It has unveiled couple of plans already.

Chandrayaan-2

Chandrayaan-2 mission is planned to have an orbiter/lander/rover configuration. The mission is

expected to be realised by 2012 - 13. The science goals of the mission is to further improve our

understanding of origin and evolution of the Moon using instruments onboard Orbiter and in-situ analysis

of lunar samples and studies of lunar regolith properties (remote & direct analysis) using Robots/Rovers.

Aditya-1

The First Indian space based Solar Coronagraph to study solar Corona in visible and near IR

bands. Launch of the Aditya mission is planned during the next high solar activity period ~ 2012. The

main objectives is to study the Coronal Mass Ejection (CME) and consequently the crucial physical

parameters for space weather such as the coronal magnetic field structures, evolution of the coronal

magnetic field etc. This will provide completely new information on the velocity fields and their variability in

the inner corona having an important bearing on the unsolved problem of heating of the corona would be

obtained.

Problems on Satellites:

In recent times satellites have been hacked by militant organizations to broadcast propaganda

and to pilfer classified information from military communication networks.[35][36]

As test, satellites in low earth orbit have been destroyed by ballistic missiles launched from earth. Russia,

the United States and China have demonstrated the ability to eliminate satellites.[37] In 2007

the Chinese military shot down an aging weather satellite,[37] followed by the US Navy shooting down

a defunct spy satellite in February 2008. Due to the low received signal strength of satellite transmissions,

they are prone to jamming by land-based transmitters. Such jamming is limited to the geographical area

within the transmitter's range. GPS satellites are potential targets for jamming,[39][40] but satellite phone and

television signals have also been subjected to jamming.

End of Life:

When satellites reach the end of their mission, satellite operators have the option of de-orbiting

the satellite, leaving the satellite in its current orbit or moving the satellite to a graveyard orbit. Historically,

due to budgetary constraints at the beginning of satellite missions, satellites were rarely designed to be

de-orbited. One example of this practice is the satellite Vanguard 1. Launched in 1958, Vanguard 1, the

4th manmade satellite put in Geocentric orbit, was still in orbit as of August 2009.[16]

Instead of being de-orbited, most satellites are either left in their current orbit or moved to a

graveyard orbit.[17] As of 2002, the FCC now requires all geostationary satellites to commit to moving to a

graveyard orbit at the end of their operational life prior to launch. It is to be taken into notice that if the

satellites are not deorbited then it might potentially slow down the satellite communication and possibly

pose a threat to end the link to satellites. There are indeed clusters of satellites(unoperational ones) out

there in the space.

Opposition

Critics such as the late physicist and Nobel prize winner Richard Feynman have contended that human space travel (as distinguished from space exploration in general, such as robotic missions) has never achieved any major scientific breakthroughs.

Disadvantages:

Astronauts risk their lives to install equipment for research

Failing space equipment hitting the earth and killing/wounding people

Possibility of infection from alien viruses and bacteria yet comets spread these too

High costs which could be used to help the needy or sponsor other experiments, yet money spent on all the space programs is paid to supplies and personnel who avian pay taxes. No cash is ever "lost" or "wasted" in space.

Advantages:

More accurate forecasts because they can use satellites to monitor the pressure of wind and temperature 

Mining minerals on the moon and planets 

Learning more about the universe and its creation

Conclusion:

The research that is conducted by national space exploration agencies, such as NASA and the RKA, is one of the reasons supporters cite to justify government expenses. Economic analyses of the NASA programs often showed ongoing economic benefits (from things such as spin-offs), generating many times the revenue of the cost of the program