54-641: The South Asia Satellite (designated GSAT-9 ), formerly known as SAARC Satellite , is a geostationary communications and meteorology satellite operated by the Indian Space Research Organisation for the South Asian Association for Regional Cooperation (SAARC) region. The satellite was launched on 5 May 2017. During the 18th SAARC summit held in Nepal in 2014, Indian Prime Minister Narendra Modi mooted
108-483: A delta-v of approximately 50 m/s per year. A second effect to be taken into account is the longitudinal drift, caused by the asymmetry of the Earth – the equator is slightly elliptical ( equatorial eccentricity ). There are two stable equilibrium points sometimes called "gravitational wells" (at 75.3°E and 108°W) and two corresponding unstable points (at 165.3°E and 14.7°W). Any geostationary object placed between
162-427: A geostationary transfer orbit (GTO), an elliptical orbit with an apogee at GEO height and a low perigee . On-board satellite propulsion is then used to raise the perigee, circularise and reach GEO. Satellites in geostationary orbit must all occupy a single ring above the equator . The requirement to space these satellites apart, to avoid harmful radio-frequency interference during operations, means that there are
216-401: A dedicated transponder for their communications. The standalone satellite has a liftoff mass of about 2,230 kg. GSAT -9 is the first Indian satellite to use electric propulsion albeit partially. It carries only 25% of the normal chemical fuel package compared to other Indian satellites, a xenon based electric propulsion system is used for orbital functions of the spacecraft. GSAT-20
270-415: A geostationary orbit in particular, it ensures that it holds the same longitude over time. This orbital period, T , is directly related to the semi-major axis of the orbit through the formula: where: The eccentricity is zero, which produces a circular orbit . This ensures that the satellite does not move closer or further away from the Earth, which would cause it to track backwards and forwards across
324-579: A geostationary satellite to globalise communications. Telecommunications between the US and Europe was then possible between just 136 people at a time, and reliant on high frequency radios and an undersea cable . Conventional wisdom at the time was that it would require too much rocket power to place a satellite in a geostationary orbit and it would not survive long enough to justify the expense, so early efforts were put towards constellations of satellites in low or medium Earth orbit. The first of these were
378-552: A higher graveyard orbit to avoid collisions. In 1929, Herman Potočnik described both geosynchronous orbits in general and the special case of the geostationary Earth orbit in particular as useful orbits for space stations . The first appearance of a geostationary orbit in popular literature was in October 1942, in the first Venus Equilateral story by George O. Smith , but Smith did not go into details. British science fiction author Arthur C. Clarke popularised and expanded
432-399: A known position) and providing an additional reference signal. This improves position accuracy from approximately 5m to 1m or less. Past and current navigation systems that use geostationary satellites include: Geostationary satellites are launched to the east into a prograde orbit that matches the rotation rate of the equator. The smallest inclination that a satellite can be launched into
486-408: A large area of the earth's surface, extending 81° away in latitude and 77° in longitude. They appear stationary in the sky, which eliminates the need for ground stations to have movable antennas. This means that Earth-based observers can erect small, cheap and stationary antennas that are always directed at the desired satellite. However, latency becomes significant as it takes about 240 ms for
540-516: A limited number of orbital slots available, and thus only a limited number of satellites can be operated in geostationary orbit. This has led to conflict between different countries wishing access to the same orbital slots (countries near the same longitude but differing latitudes ) and radio frequencies . These disputes are addressed through the International Telecommunication Union 's allocation mechanism under
594-406: A signal to pass from a ground based transmitter on the equator to the satellite and back again. This delay presents problems for latency-sensitive applications such as voice communication, so geostationary communication satellites are primarily used for unidirectional entertainment and applications where low latency alternatives are not available. Geostationary satellites are directly overhead at
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#1732764907582648-405: Is a circular geosynchronous orbit 35,786 km (22,236 mi) in altitude above Earth's equator , 42,164 km (26,199 mi) in radius from Earth's center, and following the direction of Earth's rotation . An object in such an orbit has an orbital period equal to Earth's rotational period, one sidereal day , and so to ground observers it appears motionless, in a fixed position in
702-744: Is a lot of poverty in the SAARC nations and we need scientific solutions for this". In his address to the Sri Lankan Parliament in March 2015, Narendra Modi said " Sri Lanka will take full benefit of India's satellite for the SAARC Region. This should be in Space by December 2016". The announcement of the satellite was generally met with favourable views by the SAARC nations that supported
756-542: Is also equipped with remote sensing state of the art technology which enables collection of real-time weather data and helps in observations of the geology of the South Asian nations. During the Indian general elections campaign in 2014, Prime Minister Modi hinted that his foreign policy will actively focus on improving ties with India's immediate neighbours which is being termed as Neighbourhood first policy in
810-659: Is expected to be the first fully electric propulsion system enabled satellite. The satellite was launched on 5 May 2017 at 11:27 UTC aboard the GSLV -F09 rocket from the Second Launch Pad (SLP) of the Satish Dhawan spaceport in Sriharikota , in the southern part of Andhra Pradesh . The launch was followed by a series of orbit-raising operations (using an on-board LAM and chemical thrusters) to place
864-452: Is that of the launch site's latitude, so launching the satellite from close to the equator limits the amount of inclination change needed later. Additionally, launching from close to the equator allows the speed of the Earth's rotation to give the satellite a boost. A launch site should have water or deserts to the east, so any failed rockets do not fall on a populated area. Most launch vehicles place geostationary satellites directly into
918-403: Is the gravitational constant , (6.674 28 ± 0.000 67 ) × 10 m kg s . The magnitude of the acceleration, a , of a body moving in a circle is given by: where v is the magnitude of the velocity (i.e. the speed) of the satellite. From Newton's second law of motion , the centripetal force F c is given by: As F c = F g , so that Replacing v with the equation for
972-781: Is typically 70°, and in some cases less. Geostationary satellite imagery has been used for tracking volcanic ash , measuring cloud top temperatures and water vapour, oceanography , measuring land temperature and vegetation coverage, facilitating cyclone path prediction, and providing real time cloud coverage and other tracking data. Some information has been incorporated into meteorological prediction models , but due to their wide field of view, full-time monitoring and lower resolution, geostationary weather satellite images are primarily used for short-term and real-time forecasting. Geostationary satellites can be used to augment GNSS systems by relaying clock , ephemeris and ionospheric error corrections (calculated from ground stations of
1026-408: Is used to provide visible and infrared images of Earth's surface and atmosphere for weather observation, oceanography , and atmospheric tracking. As of 2019 there are 19 satellites in either operation or stand-by. These satellite systems include: These satellites typically capture images in the visual and infrared spectrum with a spatial resolution between 0.5 and 4 square kilometres. The coverage
1080-548: The Government of Republic of India and the Government of the People's Republic of Bangladesh concerning to orbit frequency co-ordination of 'South Asia Satellite' proposed at 48.E" would cover 12 transponders of the satellite from which, 1 will be gifted to Bangladesh . Bangladesh has launched its first satellite Bangabandhu-1 on 12 May 2018. Citing the capacity of Thales Alenia Space manufactured Bangabandhu-1 satellite,
1134-428: The Indian media . Modi invited all heads of state/heads of government of SAARC countries during his swearing-in ceremony as Prime Minister of India and held bilateral talks with all of them individually, which was dubbed a "mini SAARC summit" by the media. India is only South Asian nation with orbital launch capability and builds and operates one of largest fleet of artificial satellites in world. Modi said, "There
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#17327649075821188-680: The Ministry of External Affairs of India said "Pakistan has decided to opt-out of the satellite project. So it cannot be called a SAARC satellite. It will be a South Asia satellite." There were some reports that Pakistan had security concerns, especially regarding espionage . However, the Pakistani foreign ministry said these reports were "unfounded". On 23 March 2017, Bangladesh signed the South Asia Satellite agreement with India. The agreement formally known as "Agreement between
1242-481: The Radio Regulations . In the 1976 Bogota Declaration , eight countries located on the Earth's equator claimed sovereignty over the geostationary orbits above their territory, but the claims gained no international recognition. A statite is a hypothetical satellite that uses radiation pressure from the sun against a solar sail to modify its orbit. It would hold its location over the dark side of
1296-732: The USNS Kingsport docked in Lagos on August 23, 1963. The first satellite placed in a geostationary orbit was Syncom 3 , which was launched by a Delta D rocket in 1964. With its increased bandwidth, this satellite was able to transmit live coverage of the Summer Olympics from Japan to America. Geostationary orbits have been in common use ever since, in particular for satellite television. Today there are hundreds of geostationary satellites providing remote sensing and communications. Although most populated land locations on
1350-430: The centripetal force required to maintain the orbit ( F c ) is equal to the gravitational force acting on the satellite ( F g ): From Isaac Newton 's universal law of gravitation , where F g is the gravitational force acting between two objects, M E is the mass of the Earth, 5.9736 × 10 kg , m s is the mass of the satellite, r is the distance between the centers of their masses , and G
1404-405: The speed of an object moving around a circle produces: where T is the orbital period (i.e. one sidereal day), and is equal to 86 164 .090 54 s . This gives an equation for r : The product GM E is known with much greater precision than either factor alone; it is known as the geocentric gravitational constant μ = 398 600 .4418 ± 0.0008 km s . Hence Chairman of
1458-471: The Chairman of Bangladesh Communication Satellite Company Limited (BSCL) Dr. Shahjahan Mahmood said, " Our own satellite can be used for commercial purposes and we can also sell its capacity to other countries while South Asia Satellite will be used only for limited purposes and its capacity will never be sold ." In November 2018, Bhutan announced that it is on track to begin using South Asia Satellite by
1512-424: The Earth at a latitude of approximately 30 degrees. A statite is stationary relative to the Earth and Sun system rather than compared to surface of the Earth, and could ease congestion in the geostationary ring. Geostationary satellites require some station keeping to keep their position, and once they run out of thruster fuel they are generally retired. The transponders and other onboard systems often outlive
1566-651: The Indian Space Research Organisation The chairman of the Indian Space Research Organisation is the statutory head of the Indian Space Research Organisation (ISRO). The officeholder is a secretary to the Government of India and an executive of the Department of Space (DOS) which directly reports to the prime minister of India . The Indian National Committee for Space Research (INCOSPAR)
1620-570: The SAARC member nations. It was proposed to build a satellite for the SAARC region with 12 Ku-band transponders (36 MHz each) and launch it with the Indian GSLV Mk-II . The cost of the satellite was estimated to be about ₹ 235 crore (equivalent to ₹ 330 crore or US$ 39 million in 2023), and the total cost including operational costs and insurance comes to ₹ 450 crore (equivalent to ₹ 631 crore or US$ 76 million in 2023). The cost associated with
1674-501: The SAARC satellite with SUPARCO performing technical engineering under ISRO's guidance. During the 70th UN meeting in New York City held on 20 September 2015, officials from India and Pakistan debated over the ownership and control of the satellite. On 2 October 2015, India announced that it had decided to go ahead with building the satellite, without Pakistan's consent. On 23 March 2016, Vikas Swarup , official spokesperson of
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1728-400: The absence of servicing missions from the Earth or a renewable propulsion method, the consumption of thruster propellant for station-keeping places a limitation on the lifetime of the satellite. Hall-effect thrusters , which are currently in use, have the potential to prolong the service life of a satellite by providing high-efficiency electric propulsion . For circular orbits around a body,
1782-464: The collection of artificial satellites in this orbit is known as the Clarke Belt. In technical terminology the orbit is referred to as either a geostationary or geosynchronous equatorial orbit, with the terms used somewhat interchangeably. The first geostationary satellite was designed by Harold Rosen while he was working at Hughes Aircraft in 1959. Inspired by Sputnik 1 , he wanted to use
1836-520: The concept in a 1945 paper entitled Extra-Terrestrial Relays – Can Rocket Stations Give Worldwide Radio Coverage? , published in Wireless World magazine. Clarke acknowledged the connection in his introduction to The Complete Venus Equilateral . The orbit, which Clarke first described as useful for broadcast and relay communications satellites, is sometimes called the Clarke orbit. Similarly,
1890-401: The end of November 2018. Planned utilisation of allotted Ku-band transponder includes connecting three off-grid blocks in remote areas of the country, national TV broadcast, emergency communications and backup for domestic/international voice connectivity. In November 2015, ISRO chairman A. S. Kiran Kumar stated that the satellite could be launched within 18 months of receiving approval from
1944-659: The equator and appear lower in the sky to an observer nearer the poles. As the observer's latitude increases, communication becomes more difficult due to factors such as atmospheric refraction , Earth's thermal emission , line-of-sight obstructions, and signal reflections from the ground or nearby structures. At latitudes above about 81°, geostationary satellites are below the horizon and cannot be seen at all. Because of this, some Russian communication satellites have used elliptical Molniya and Tundra orbits, which have excellent visibility at high latitudes. A worldwide network of operational geostationary meteorological satellites
1998-474: The equilibrium points would (without any action) be slowly accelerated towards the stable equilibrium position, causing a periodic longitude variation. The correction of this effect requires station-keeping maneuvers with a maximal delta-v of about 2 m/s per year, depending on the desired longitude. Solar wind and radiation pressure also exert small forces on satellites: over time, these cause them to slowly drift away from their prescribed orbits. In
2052-553: The following properties: An inclination of zero ensures that the orbit remains over the equator at all times, making it stationary with respect to latitude from the point of view of a ground observer (and in the Earth-centered Earth-fixed reference frame). The orbital period is equal to exactly one sidereal day. This means that the satellite will return to the same point above the Earth's surface every (sidereal) day, regardless of other orbital properties. For
2106-523: The ground. All geostationary satellites have to be located on this ring. A combination of lunar gravity, solar gravity, and the flattening of the Earth at its poles causes a precession motion of the orbital plane of any geostationary object, with an orbital period of about 53 years and an initial inclination gradient of about 0.85° per year, achieving a maximal inclination of 15° after 26.5 years. To correct for this perturbation , regular orbital stationkeeping maneuvers are necessary, amounting to
2160-489: The idea of a satellite serving the needs of SAARC member nations as a part of his neighbourhood first policy . Afghanistan , Bangladesh , Bhutan , Maldives , Nepal and Sri Lanka are the users of the multi-dimensional facilities provided by the satellite. Pakistan "offered technical and monetary support" which India rejected saying that it wanted the project to be a "gift" and multi-national collaboration would be time-consuming. Pakistan later on declined to participate in
2214-591: The launch was met by the Government of India . The satellite will enable a full range of applications and services in the areas of telecommunication and broadcasting applications viz television (TV), direct-to-home (DTH), very small aperture terminals (VSATs), tele-education, tele-medicine and disaster management support. It will provide communication channels for better coordination during disaster management , and will help countries in mapping terrain and natural resources. GSAT -9 carries 12 K u band transponders; each participating South Asian Country has access to
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2268-538: The passive Echo balloon satellites in 1960, followed by Telstar 1 in 1962. Although these projects had difficulties with signal strength and tracking, issues that could be solved using geostationary orbits, the concept was seen as impractical, so Hughes often withheld funds and support. By 1961, Rosen and his team had produced a cylindrical prototype with a diameter of 76 centimetres (30 in), height of 38 centimetres (15 in), weighing 11.3 kilograms (25 lb), light and small enough to be placed into orbit. It
2322-476: The planet now have terrestrial communications facilities ( microwave , fiber-optic ), with telephone access covering 96% of the population and internet access 90%, some rural and remote areas in developed countries are still reliant on satellite communications. Most commercial communications satellites , broadcast satellites and SBAS satellites operate in geostationary orbits. Geostationary communication satellites are useful because they are visible from
2376-485: The position in the sky where the satellites are located. Weather satellites are also placed in this orbit for real-time monitoring and data collection, and navigation satellites to provide a known calibration point and enhance GPS accuracy. Geostationary satellites are launched via a temporary orbit , and placed in a slot above a particular point on the Earth's surface. The orbit requires some stationkeeping to keep its position, and modern retired satellites are placed in
2430-423: The program, specifically from Sri Lanka and Bangladesh . Pakistan maintains its own space program under its Space and Upper Atmosphere Research Commission (SUPARCO), which has launched satellites on Chinese satellite launch vehicles in the past. Pakistan initially declared that it was "keen" to participate on the project, offering monetary and technical support. However, Pakistan said it did not because "India
2484-495: The project citing India's refusal to collaboration and security reasons. Afghanistan too was initially non-committal to the satellite which led to renaming of satellite from "SAARC Satellite" to "South Asia Satellite" referring just to the subcontinent . As of 2019 with exception of Pakistan, the satellite is in service with all SAARC countries. The South Asia Satellite provides crucial information on tele-medicine, tele-education, banking and television broadcasting opportunities. It
2538-524: The same plane, altitude and speed; however, the presence of satellites in eccentric orbits allows for collisions at up to 4 km/s. Although a collision is comparatively unlikely, GEO satellites have a limited ability to avoid any debris. At geosynchronous altitude, objects less than 10 cm in diameter cannot be seen from the Earth, making it difficult to assess their prevalence. Despite efforts to reduce risk, spacecraft collisions have occurred. The European Space Agency telecom satellite Olympus-1
2592-438: The satellite in the intended geostationary orbital slot. Sri Lankan President Maithripala Sirisena congratulated Modi using satellite technology and claimed that it would help uplift the standards of people. Nepalese officials commented on Nepalese current inability to fully utilize the satellite information. Geostationary orbit A geostationary orbit , also referred to as a geosynchronous equatorial orbit ( GEO ),
2646-405: The sky. A geostationary orbit can be achieved only at an altitude very close to 35,786 kilometres (22,236 miles) and directly above the equator. This equates to an orbital speed of 3.07 kilometres per second (1.91 miles per second) and an orbital period of 1,436 minutes, one sidereal day . This ensures that the satellite will match the Earth's rotational period and has a stationary footprint on
2700-435: The sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications, and the first satellite to be placed in this kind of orbit was launched in 1963. Communications satellites are often placed in a geostationary orbit so that Earth-based satellite antennas do not have to rotate to track them but can be pointed permanently at
2754-485: The thruster fuel and by allowing the satellite to move naturally into an inclined geosynchronous orbit some satellites can remain in use, or else be elevated to a graveyard orbit . This process is becoming increasingly regulated and satellites must have a 90% chance of moving over 200 km above the geostationary belt at end of life. Space debris at geostationary orbits typically has a lower collision speed than at low Earth orbit (LEO) since all GEO satellites orbit in
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#17327649075822808-566: Was spin stabilised with a dipole antenna producing a pancake shaped beam. In August 1961, they were contracted to begin building the real satellite. They lost Syncom 1 to electronics failure, but Syncom 2 was successfully placed into a geosynchronous orbit in 1963. Although its inclined orbit still required moving antennas, it was able to relay TV transmissions, and allowed for US President John F. Kennedy in Washington D.C., to phone Nigerian prime minister Abubakar Tafawa Balewa aboard
2862-574: Was not willing to develop the project on a collaborative basis." Pakistan also stated it was working on its own satellite under its existing space commitments, thus declined to join the project. The Indian government declined Pakistani offers of technical and monetary help because it wanted the project to be an Indian "gift" and did not want to make it into a "SAARC project", and that collaborations with Pakistan would have taken some time. Earlier on 27 June 2015, ISRO chairman A. S. Kiran Kumar had announced that India and Pakistan would collaborate on developing
2916-499: Was struck by a meteoroid on August 11, 1993, and eventually moved to a graveyard orbit , and in 2006 the Russian Express-AM11 communications satellite was struck by an unknown object and rendered inoperable, although its engineers had enough contact time with the satellite to send it into a graveyard orbit. In 2017, both AMC-9 and Telkom-1 broke apart from an unknown cause. A typical geostationary orbit has
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