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33-415: INSAT-4E has five C x S transponders each of 9 MHz bandwidth and five S x C transponders each of 2.7 MHz bandwidth which will together cover the entire country. GSAT-6 uses a 0.8 meter (fixed) and one 6 meter S-Band unfurlable antenna (transmit and receive). The unfurlable antenna weighing 18 kg has CFRP truss construction with aluminium alloy joints and its parabolic gold plated molybdenum mesh

66-464: A supersynchronous transfer orbit where the apogee (and the maneuver to reduce the transfer orbit inclination) are at a higher altitude than 35,786 km, the geosynchronous altitude. Proton even offers to perform a supersynchronous apogee maneuver up to 15 hours after launch. The geostationary orbit is a special type of orbit around the Earth in which a satellite orbits the planet at the same rate as

99-440: A High Thrust Vikas engine (HTVE) was inducted on second stage (GS2) of GSLV with 6% higher thrust than before. The improved engine increased the payload capability of the vehicle. The electrohydraulic actuation system on second stage was also replaced with simpler and robust electromechanical system. The Cryogenic Upper Stage of GSLV F08 performed a burn to depletion for the first time. Officials said any improvement done to

132-416: A geostationary orbit. If only the eccentricity of the orbit is reduced to zero, the result may be a geosynchronous orbit but will not be geostationary. Because the Δ V {\displaystyle \Delta V} required for a plane change is proportional to the instantaneous velocity, the inclination and eccentricity are usually changed together in a single maneuver at apogee, where velocity

165-464: A spacecraft already in a low Earth orbit ( LEO ) can enter GTO by firing a rocket along its orbital direction to increase its velocity. This was done when geostationary spacecraft were launched from the Space Shuttle ; a "perigee kick motor" attached to the spacecraft ignited after the shuttle had released it and withdrawn to a safe distance. Although some launchers can take their payloads all

198-435: Is a highly elliptical Earth orbit with an apogee (the point in the orbit of the moon or a satellite at which it is furthest from the earth) of 42,164 km (26,199 mi), or a height of 35,786 km (22,236 mi) above sea level, which corresponds to the geostationary altitude. The period of a standard geosynchronous transfer orbit is about 10.5 hours. The argument of perigee is such that apogee occurs on or near

231-553: Is a highly elliptical type of geocentric orbit , usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit (GEO). Satellites that are destined for geosynchronous orbit (GSO) or GEO are often put into a GTO as an intermediate step for reaching their final orbit. Manufacturers of launch vehicles often advertise the amount of payload the vehicle can put into GTO. Geostationary and geosynchronous orbits are very desirable for many communication and Earth observation satellites . However,

264-422: Is lowest. The required Δ V {\displaystyle \Delta V} for an inclination change at either the ascending or descending node of the orbit is calculated as follows: For a typical GTO with a semi-major axis of 24,582 km, perigee velocity is 9.88 km/s and apogee velocity is 1.64 km/s, clearly making the inclination change far less costly at apogee. In practice,

297-550: Is supported and shaped by cable mesh structures. The cost of GSAT-6 satellite is ₹232 crore and it is identical in configuration to GSAT-6A which was launched later. ISRO successfully launched INSAT-4E on 27 August 2015, using a GSLV D6 Mk.II rocket flying from the Satish Dhawan Space Centre and inserted into a Geostationary Transfer Orbit (GTO) with injection parameters of 170 km x 35945 km, 19.96 degree inclination. The cost of launch vehicle

330-542: Is the velocity magnitude at the apogee of the transfer orbit and V GEO {\displaystyle V_{\text{GEO}}} is the velocity in GEO. Even at apogee, the fuel needed to reduce inclination to zero can be significant, giving equatorial launch sites a substantial advantage over those at higher latitudes. Russia 's Baikonur Cosmodrome in Kazakhstan is at 46° north latitude. Kennedy Space Center in

363-598: The Indian Armed Forces . GSLV-F08 carrying GSAT-6A spacecraft was launched from Second Launch Pad of Satish Dhawan Space Centre on 29 March 2018, 11:26 UTC and after flight of 17 minutes 45 seconds, placed GSAT-6A into its planned geostationary transfer orbit with 36,692.5 kilometres (22,799.7 mi) apogee, 169.4 kilometres (105.3 mi) perigee and orbital inclination of 20.64°. GSAT-6A spacecraft deployed its solar array after separation from CUS and established contact with ground station. On GSLV-F08,

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396-604: The United States is at 28.5° north. China 's Wenchang is at 19.5° north. India 's SDSC is at 13.7° north. Guiana Space Centre , the European Ariane and European-operated Russian Soyuz launch facility, is at 5° north . The "indefinitely suspended" Sea Launch launched from a floating platform directly on the equator in the Pacific Ocean . Expendable launchers generally reach GTO directly, but

429-406: The delta-v , and therefore financial, cost to send a spacecraft to such orbits is very high due to their high orbital radius. A GTO is an intermediary orbit used to make this process more efficient. Satellite operators often use a high-thrust, low-efficiency launch vehicle to put their satellite into GTO, and then, after detaching the launch vehicle, use low-thrust, high-efficiency thrusters onboard

462-506: The GSAT-6 satellite has remained largely underutilized since its launch in August 2015 which is almost half of the expected operational life of 12 years. The audit observed the lack of coordination between Department of Space and DRDO and the delay in establishing ground segment by DRDO as the reason behind this disuse. According to Department of Space the 20 per cent of the GSAT-6 capacity

495-539: The Hohmann transfer orbit, only a few days are required to reach the geosynchronous orbit. By using low-thrust engines or electrical propulsion, months are required until the satellite reaches its final orbit. The orbital inclination of a GTO is the angle between the orbit plane and the Earth's equatorial plane . It is determined by the latitude of the launch site and the launch azimuth (direction). The inclination and eccentricity must both be reduced to zero to obtain

528-511: The argument of perigee is slowly perturbed by the oblateness of the Earth, it is usually biased at launch so that it reaches the desired value at the appropriate time (for example, this is usually the sixth apogee on Ariane 5 launches ). If the GTO inclination is zero, as with Sea Launch , then this does not apply. (It also would not apply to an impractical GTO inclined at 63.4°; see Molniya orbit .) The preceding discussion has primarily focused on

561-464: The capacity (adapter and spacecraft mass) of the Delta IV Heavy is 14,200 kg to GTO, or 6,750 kg directly to geostationary orbit. If the maneuver from GTO to GEO is to be performed with a single impulse, as with a single solid-rocket motor, apogee must occur at an equatorial crossing and at synchronous orbit altitude. This implies an argument of perigee of either 0° or 180°. Because

594-589: The case where the transfer between LEO and GEO is done with a single intermediate transfer orbit. More complicated trajectories are sometimes used. For example, the Proton-M uses a set of three intermediate orbits, requiring five upper-stage rocket firings, to place a satellite into GEO from the high-inclination site of Baikonur Cosmodrome , in Kazakhstan . Because of Baikonur's high latitude and range safety considerations that block launches directly east, it requires less delta-v to transfer satellites to GEO by using

627-406: The equator. Perigee can be anywhere above the atmosphere, but is usually restricted to a few hundred kilometers above the Earth's surface to reduce launcher delta-V ( Δ V {\displaystyle \Delta V} ) requirements and to limit the orbital lifetime of the spent booster so as to curtail space junk. If using low-thrust engines such as electrical propulsion to get from

660-446: The geostationary transfer orbits. The thrust direction and magnitude are usually determined to optimize the transfer time and/or duration while satisfying the mission constraints. The out-of-plane component of thrust is used to reduce the initial inclination set by the initial transfer orbit, while the in-plane component simultaneously raises the perigee and lowers the apogee of the intermediate geostationary transfer orbit. In case of using

693-489: The inclination change is combined with the orbital circularization (or " apogee kick ") burn to reduce the total Δ V {\displaystyle \Delta V} for the two maneuvers. The combined Δ V {\displaystyle \Delta V} is the vector sum of the inclination change Δ V {\displaystyle \Delta V} and the circularization Δ V {\displaystyle \Delta V} , and as

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726-428: The satellite into a geosynchronous transfer orbit. Due to power failure during its orbit raising burns the communication was lost with GSAT-6A before it could reach its final circular geostationary orbit (GSO). GSAT-6A was launched to complement GSAT-6 satellite which was launched in August 2015 by ISRO. The cost of building GSAT-6A was around ₹270 crore . GSAT-6A was to provide mobile communication services to

759-518: The satellite itself to circularize its orbit (to GEO) over a longer period of time. This process is called spiral-out . This mission architecture is useful because it minimizes the mass that the spacecraft must push to GEO, allows for maximally efficient circularization burns taking advantage of the Oberth effect , and allows the spent launch vehicle to deorbit primarily through aerobraking due to its low perigee, minimizing its orbital lifetime . GTO

792-457: The spacecraft supports the mission after launcher separation. Also, many launchers now carry several satellites in each launch to reduce overall costs, and this practice simplifies the mission when the payloads may be destined for different orbital positions. Because of this practice, launcher capacity is usually quoted as spacecraft mass to GTO, and this number will be higher than the payload that could be delivered directly into GEO. For example,

825-420: The sum of the lengths of two sides of a triangle will always exceed the remaining side's length, total Δ V {\displaystyle \Delta V} in a combined maneuver will always be less than in two maneuvers. The combined Δ V {\displaystyle \Delta V} can be calculated as follows: where V t , a {\displaystyle V_{t,a}}

858-428: The transfer orbit to geostationary orbit, the transfer orbit can be supersynchronous (having an apogee above the final geosynchronous orbit). However, this method takes much longer to achieve due to the low thrust injected into the orbit. The typical launch vehicle injects the satellite to a supersynchronous orbit having the apogee above 42,164 km. The satellite's low-thrust engines are thrusted continuously around

891-509: The unfurlable antenna (UFA) also successfully completed with this. The satellite was at 78 degrees east longitude and was drifting towards its final slot at 83 degrees east. GSAT-6 was successfully positioned in its orbital slot of 83 degree east and collocated with INSAT-4A , GSAT-12 , GSAT-10 and IRNSS-1C on September 6, 2015, morning, after carrying out four drift arresting maneuvers. According to Comptroller and Auditor General of India report submitted to parliament in 20 December 2022,

924-499: The vehicle would be incorporated into GSLV's future missions. The first orbit raising maneuver for GSAT-6A was carried out as planned on 30 March 2018 by firing the Liquid Apogee Motor (LAM) for 2188 seconds from 09:22 AM IST. The second orbit raising maneuver was carried out at 10:00 AM on 31 March 2018. As the satellite was on-course for its third and final orbit raising maneuver on 1 April 2018, communication with it

957-424: The way to geostationary orbit, most end their missions by releasing their payloads into GTO. The spacecraft and its operator are then responsible for the maneuver into the final geostationary orbit. The 5-hour coast to first apogee can be longer than the battery lifetime of the launcher or spacecraft, and the maneuver is sometimes performed at a later apogee or split among multiple apogees. The solar power available on

990-600: Was around ₹276 crore. Maneuvers to move the satellite into its designated geosynchronous orbit at 83 degrees East longitude were initiated on 28 August 2015 by firing motors on board the GSAT-6 satellite. The GSAT-6 satellite's Liquid Apogee Motor (LAM) was fired for 3385 seconds at 08:35 hours IST on August 28 during the first orbit raising operation and modified the satellite orbit to 8,408 km (perigee height) by 35,708 km (apogee height) with an inclination of 7.5 degree and an orbital period of 13 hours, 15 minutes and 24 seconds. Second orbit raising operation of GSAT-6

1023-456: Was lost and the spacecraft was temporarily untraceable. After regaining its track, efforts to re-establish communication with the satellite could not succeed. Power system malfunction was suspected to be the reason behind loss of contact. ISRO will launch GSAT-32 satellite as replacement for GSAT-6A. Geostationary transfer orbit In space mission design, a geostationary transfer orbit ( GTO ) or geosynchronous transfer orbit

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1056-506: Was successfully completed by firing the Apogee Motor for 2663 seconds at 11:10:53 hours IST on Aug 29, 2015. Realized orbit was 26,998 km (perigee height) by 35,682 km (apogee height) with an inclination of 0.115 degree and an orbital period of 20 hours and 15 minutes. Third orbit raising operation of GSAT-6 was successfully completed by firing the Apogee Motor for 580.32 seconds at 07:46 hours IST on Aug 30, 2015. Deployment of

1089-569: Was used for its research projects and societal applications but was not aware of the status of utilization of the remaining capacity. GSAT-6A GSAT-6A was a communication satellite launched by the Indian Space Research Organisation (ISRO). It featured a 6-metre (20 ft) unfurlable S-band antenna similar to the one used on GSAT-6 . Around 17 minutes after lift-off, the three stage GSLV Mk.II rocket flying on GSLV F08 mission successfully injected

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