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<\/p>\nIndia launched an upgraded version of its Geosynchronous Satellite Launch Vehicle Thursday, carrying the GSAT-6A communications satellite into orbit. Liftoff, from the Satish Dhawan Space Centre, occurred at 16:56 local time (11:26 UTC).<\/p>\n
In the first of three planned orbital launches worldwide on Thursday, India\u2019s Geosynchronous Satellite Launch Vehicle (GSLV) debuted an enhanced second stage with a more powerful engine. The rocket deployed GSAT-6A, a communications satellite, for the Indian Space Research Organisation (ISRO).<\/p>\n
The GSAT-6A mission is a follow-up to GSAT-6, which was successfully deployed by a GSLV in August 2015. Like GSAT-6, GSAT-6A will relay communications from mobile handheld terminals used by India\u2019s military. To facilitate this, each satellite carries ten S-band transponders and an unfurlable six-meter (20-foot) antenna, as well as a C-band payload with an 80-centimeter (2.6-foot) antenna. GSAT-6A will be co-located with GSAT-6 in geostationary orbit at a longitude of 83 degrees East, where it is expected to operate for at least ten years.<\/p>\n
Built by ISRO, the GSAT-6A spacecraft is based around an I-2K satellite bus. It has a mass of 2,140 kilograms (4,718 lb) and measures 1.53 by 1.65 by 2.4 meters (5.02 by 5.41 by 7.87 feet) stowed. The satellite will generate 3.1 kilowatts of power through two deployable solar arrays.<\/p>\n
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GSAT-6A \u2013 via ISRO<\/p>\n
Thursday\u2019s launch used the Mark II version of India\u2019s three-stage Geosynchronous Satellite Launch Vehicle (GSLV Mk.II) \u2013 with its flight designated GSLV F08. Using a combination of liquid and solid-fuelled stages, the GSLV was designed to place communications satellites into geosynchronous transfer orbits. To this end, GSLV has increased performance over the smaller Polar Satellite Launch Vehicle (PSLV), from which it is derived.<\/p>\n
GSLV\u2019s first stage consists of a solid-fuelled core, with four radially-mounted liquid-fuelled strap-ons. The strap-ons are part of the first stage, and do not separate from the core. GSLV\u2019s second stage, which is closely related to PSLV\u2019s second stage, burns hypergolic liquid propellants, while the rocket\u2019s third stage uses cryogenic fuel.<\/p>\n
The GSLV made its maiden flight in April 2001, carrying the experimental GSAT-1 communications satellite. The launch failed \u2013 with the rocket\u2019s third stage shutting down too soon and leaving GSAT-1 in a lower-than-planned orbit. ISRO attempted to correct the satellite\u2019s orbit using its own propulsion, but a design flaw in its fuel feed system led to the spacecraft running out of propellant before it could raise its orbit\u2019s perigee to geostationary altitude.<\/p>\n
Early GSLV missions used the Mark I version of the rocket, which incorporated a Russian-built KVD-1M third-stage engine. The Mark II, which has a stretched third stage with an Indian engine, first flew in April 2010 but its new engine failed to ignite. The first successful Mk.II launch took place in January 2014. India also has a GSLV Mk.III. However, this is a completely new rocket that reached orbit for the first time last year.<\/p>\n
Excluding the Mk.III, Thursday\u2019s launch was GSLV\u2019s twelfth flight. In its previous eleven launches, GSLV has recorded six successes, four failures and one partial failure. The failures occurred on the rocket\u2019s first, fourth, sixth and seventh launches \u2013 while the rocket\u2019s upper stage underperformed during the fifth launch \u2013 placing the INSAT-4CR satellite into a lower-than-planned orbit. Unlike GSAT-1, INSAT-4CR was able to correct its own orbit. GSLV\u2019s current run of four consecutive successful launches is the longest that the rocket has achieved.<\/p>\n
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The GSLV for this latest launch \u2013 via ISRO<\/p>\n
Thursday\u2019s launch introduced upgrades to GSLV\u2019s second stage, with an uprated engine and the replacement of hydraulic components with electromechanical systems. The High Thrust Vikas Engine (HTVE) replaces a standard Vikas engine that was used on the second stage in previous flights. HTVE has a higher chamber pressure \u2013 6,200 kilopascals (899 psi) instead of 5,800 kPa (841 psi) \u2013 increasing its thrust. Vikas is an Indian license-built version of the French Viking engine, which powered Europe\u2019s Ariane 1, 2, 3 and 4 rockets.<\/p>\n
The stage\u2019s new electromechanical components will simplify the rocket\u2019s systems, with a view to improving reliability.<\/p>\n
As a result of the upgrades, GSLV\u2019s payload capacity to geosynchronous transfer orbit (GTO) has been increased by about 70 kilograms (150 lb). Once Thursday\u2019s launch has validated the HTVE in flight, ISRO will incorporate the new engines in an upgraded version of GSLV\u2019s first stage for future launches, while improvements to the third stage are also planned. This further upgraded GSLV will be used to launch ISRO\u2019s Chandrayaan-2 mission to the Moon later this year and can carry a further 180 kilograms (400 lb) to GTO.<\/p>\n
Thursday\u2019s launch took place from the Second Launch Pad (SLP) at ISRO\u2019s Satish Dhawan Space Centre (SDSC). Satish Dhawan \u2013 which was named the Sriharikota High Altitude Range (SHAR) until 2002 \u2013 has been the site of all of India\u2019s orbital launches. ISRO\u2019s early rockets \u2013 the Satellite Launch Vehicle (SLV) and Augmented (or Advanced) Satellite Launch Vehicle (ASLV) flew from now-disused pads to the south of the active First and Second Launch Pads. The First Launch Pad (FLP) came on-line in 1993 with the PSLV\u2019s maiden flight, while the second pad was first used in May 2005.<\/p>\n
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GSLV heading to the pad \u2013 via ISRO<\/p>\n
PSLV and GSLV rockets can \u2013 and have \u2013 flown from both the First and Second Launch Pads, although no GSLV missions have used the First Launch Pad since construction of the Second Launch Pad was completed. The larger GSLV Mk.III can only fly from the second pad.<\/p>\n
In preparation for Thursday\u2019s launch, the GSLV was integrated vertically in the Vehicle Assembly Building, located about a kilometer (0.6 miles) southwest of the launch pad. The rocket was transported to the pad, atop its mobile launch platform, a few days ahead of the planned launch. The twenty-seven-hour countdown began at 13:56 local time (09:26 UTC) on Wednesday.<\/p>\n
GSLV\u2019s first stage \u2013 or GS1 \u2013 consists of an S-139 solid rocket motor with four L-40H boosters attached to it. Each L-40H is powered by a Vikas engine, burning UH-25 propellant \u2013 a mix of two parts unsymmetrical dimethylhydrazine and one part hydrazine hydrate \u2013 oxidized by dinitrogen tetroxide (N2O2).<\/p>\n
The four Vikas engines on the first stage boosters ignited about 4.8 seconds before Thursday\u2019s countdown reaches zero, with the S-139 igniting at the zero mark. With the core motor lit, GSLV F-08 lifted off to begin its journey into orbit. Shortly after liftoff, GSLV pitched over and fly East of Sriharikota, on a planned azimuth of 106 degrees.<\/p>\n
The S-139 motor burned for about 106 seconds before exhausting its propellant. The liquid-fuelled boosters continued to burn for another 43 seconds before emptying their own propellant tanks. Six tenths of a second after the first stage\u2019s liquid-fuelled engines burnt out, the second stage ignited \u2013 testing its HTVE engine in flight for the first time. The first stage does not separate until 1.6 seconds after second stage ignition.<\/p>\n
The second stage of GSLV \u2013 the GS2 or L-37.5H \u2013 is powered by the single HTVE engine which burns the same combination of UH-25 and dinitrogen tetroxide as the L-40H boosters. It fired for 136 seconds, with the rocket\u2019s payload fairing separating 74 seconds into the burn. The fairing \u2013 which protects GSLV\u2019s payload as the rocket ascends through the atmosphere \u2013 was no longer needed once the vehicle enters space and is discarded to save weight.<\/p>\n
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Mission Profile \u2013 via ISRO<\/p>\n
Three and a half seconds after second stage cutoff, the stage was jettisoned. One second later the Cryogenic Upper Stage (CUS) ignited. The CUS \u2013 also known as GS3 or C12.5 \u2013 is powered by a CE7.5 engine providing 7.5 tonnes (73.5 kilonewtons, 16,500 pounds-force) of thrust. It burns liquid hydrogen propellant, oxidized by liquid oxygen.<\/p>\n
The upper stage burned for twelve minutes and 45-50 seconds, accelerating GSAT-6A to a peak velocity of 9.75 kilometers (6.06 miles, 5.26 nautical miles) per second \u2013 or 21,800 miles per hour. The exact burn time is not known as the third stage will burn until it runs out of liquid oxygen, instead of cutting off once a specific target is reached.<\/p>\n
GSAT-6A separated from the GSLV 17 minutes and 46.5 seconds after liftoff \u2013 about ten to fifteen seconds after third stage depletion. The target orbit for spacecraft deployment is 170 by 35,975 kilometers (105 by 22,353 miles; 91 by 19,424 nautical miles), inclined at 20.63 degrees to the equator.<\/p>\n
GSAT-6A will perform three orbit-raising maneuvers to effect a combined change in velocity of 1.66 kilometers (1.03 miles, 0.90 nautical miles) per second \u2013 or 3,713 miles per hour. This will leave the spacecraft in its planned geostationary orbit.<\/p>\n
Thursday\u2019s launch was India\u2019s second of 2018, following a successful PSLV mission in January that deployed Cartosat-2F. ISRO will next be in action around 12 April, with a PSLV due to place the IRNSS-1I navigation satellite into orbit. GSLV is next expected to fly in October, when it will carry Chandrayaan-2 on the first leg of its mission to the Moon.<\/p>\n","protected":false},"excerpt":{"rendered":"
India launched an upgraded version of its Geosynchronous Satellite Launch Vehicle Thursday, carrying the GSAT-6A communications satellite into orbit. Liftoff, from the Satish Dhawan Space Centre, occurred at 16:56 local time (11:26 UTC). In the first of three planned orbital launches worldwide on Thursday, India\u2019s Geosynchronous Satellite Launch Vehicle (GSLV) debuted an enhanced second stage […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1259,525],"class_list":["post-38496","post","type-post","status-publish","format-standard","hentry","category-news","tag-gslv","tag-isro"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38496"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=38496"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38496\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=38496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=38496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=38496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}