GSAT-6A - GSLV-F08 (Mk-II) - Шрихарикота - 29.03.2018, 11:26 UTC

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https://www.isro.gov.in/update/27-mar-2018/mission-readiness-review-mrr-committee-and-launch-authorization-board-lab-have

Mar 27, 2018

Mission Readiness Review (MRR) committee and Launch Authorization Board (LAB) have cleared the 27 hr countdown activities starting at 13:56hr IST on Wednesday, March 28, 2018 and the launch of GSLV-F08/GSAT-6A for Thursday, March 29, 2018 at 16:56hr IST

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https://www.isro.gov.in/update/28-mar-2018/27-hrs-countdown-activities-launch-of-gslv-f08-gsat-6a-mission-have-started-1356

Mar 28, 2018

The 27 Hrs Countdown activities for the launch of GSLV-F08 / GSAT-6A Mission have started at 13:56 Hrs IST on Wednesday, March 28, 2018.

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https://www.isro.gov.in/gslv-f08-gsat-6a-mission/gslv-f08-gsat-6a-mission-curtain-raiser-video-english

GSLV-F08/GSAT-6A Mission Curtain Raiser Video - English

(video)

Description: GSLV-F08/GSAT-6A Mission Curtain Raiser Video - English
Format : MP4
File Size : 69.81 MB
Duration : 00:08:20
Plugin : NA

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https://www.isro.gov.in/update/28-mar-2018/preparations-gslv-f08-second-stage-gs2-propellant-filling-operation-are-under

Mar 28, 2018

Preparations for GSLV-F08 Second stage (GS2) propellant filling operation are under progress

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https://www.isro.gov.in/update/28-mar-2018/second-stage-gs2-n2o4-filling-under-progress

Mar 28, 2018

Second Stage (GS2) N2O4 filling under progress

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https://www.isro.gov.in/update/28-mar-2018/second-stage-gs2-n2o4-filling-completed-1615-hr-ist

Mar 28, 2018

Second Stage (GS2) N2O4 filling completed by 16:15 hr IST

10:45 UTC

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https://www.isro.gov.in/update/28-mar-2018/preparation-second-stage-gs2-uh25-filling-under-progress

Mar 28, 2018

Preparation for Second Stage (GS2) UH25 filling is under progress

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https://www.isro.gov.in/update/28-mar-2018/second-stage-gs2-uh25-filling-under-progress

Mar 28, 2018

Second Stage (GS2) UH25 filling is under progress.

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ISRO‏Подлинная учетная запись @isro 12 ч. назад

GSLV-F08/GSAT-6A Mission https://www.isro.gov.in/launcher/gslv-f08-gsat-6a-mission ...

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https://www.isro.gov.in/update/28-mar-2018/second-stage-gs2-uh25-filling-completed-1945-hr-ist

Mar 28, 2018

Second Stage (GS2) UH25 filling is completed by 19:45 hr IST

14:15 UTC

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https://www.isro.gov.in/update/28-mar-2018/propellant-filling-operation-of-l40-stages-under-progress-countdown-progressing

Mar 28, 2018

Propellant filling operation of L40 Stages is under progress. Countdown is progressing normally.

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https://www.isro.gov.in/update/29-mar-2018/propellant-filling-operation-of-l40-stages-completed-0220-hr-ist

Mar 29, 2018

Propellant filling operation of L40 Stages is completed by 02:20 hr IST.

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https://www.isro.gov.in/update/29-mar-2018/real-time-system-simulation-checks-completed-countdown-progressing-normally

Mar 29, 2018

Real Time System simulation checks Completed. Countdown is progressing normally.

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https://www.isro.gov.in/update/29-mar-2018/preparations-propellant-filling-of-cryo-stage-are-under-progress

Mar 29, 2018

Preparations for propellant filling of cryo stage are under progress

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Трансляция на сайте ISRO

https://www.isro.gov.in/gslv-f08-gsat-6a-mission/launch-of-gslv-f08-gsat-6a-mission-watch-live-1630-hrs-ist

Launch of GSLV-F08 / GSAT-6A Mission - Watch live from 16:30 hrs (IST)

11:00 UTC

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Chris B - NSF‏ @NASASpaceflight 5 ч. назад

ARTICLE: Indian GSLV set for GSAT-6A launch -

https://www.nasaspaceflight.com/2018/03/indian-gslv-set-for-gsat-6a-launch/ ...

- By William Graham

Спойлер

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https://spaceflightnow.com/2018/03/29/gslv-f08-mission-status-center/

Live coverage: Indian GSLV set for launch with communications satellite
March 29, 2018 | Stephen Clark

Upd ated: 03/29/2018 07:41 Stephen Clark

An Indian Geosynchronous Satellite Launch Vehicle debuting an upgraded higher-thrust second stage engine is set for liftoff Thursday with an S-band communications satellite.

The GSLV Mk.2 launcher is scheduled for takeoff at 1126 GMT (7:26 a.m. EDT; 4:56 p.m. Indian time) Thursday, flying off the Second Launch Pad at the Satish Dhawan Space Center on India's east coast.

Спойлер

Standing 161 feet (49 meters) tall, the GSLV Mk.2 aims to place the Indian-built GSAT 6A communications satellite into an elliptical transfer orbit, a drop-off point on the way to the spacecraft's final orbital perch in geostationary orbit nearly 22,300 miles (35,800 kilometers) over the equator.

Crews at the Indian spaceport on Sriharikota Island transferred the GSLV Mk.2 rocket to its launch pad earlier this month after its build-up inside a vertical hangar. The roughly kilometer-long rollout fr om the Vehicle Assembly Building to the space base's so-called Second Launch Pad occurred along rail tracks, and three swiveling access arms swung into position around the rocket after it arrived at the launch complex.

A launch authorization board convened Tuesday and gave approval to begin the GSLV Mk.2's 27-hour countdown Wednesday.

The mixture of hydrazine and nitrogen tetroxide propellants to be consumed by the rocket's second stage Vikas engine was loaded into the GSLV Mk.2 on Wednesday. The same propellant combination will be pumped into the rocket's four liquid-fueled boosters Thursday, followed by filling of the GSLV Mk.2's third stage with super-cold liquid hydrogen and liquid oxygen.

The launcher's first stage burns pre-packed solid propellants.

Thursday's launch will be the 12th flight of India's GSLV Mk.1 and Mk.2 rocket family since 2001, and the sixth to use an Indian-built cryogenic third stage engine. Six previous missions flown in the GSLV Mk.1 configuration launched with a Russian-manufactured upper stage engine before Indian engineers completed development of a domestic cryogenic engine.

The GSLV Mk.2 has logged four successful missions in a row after the four previous GSLV flights -- including both Mk.1 and Mk.2 versions -- suffered total or partial failures.

The rocket awaiting liftoff Thursday features two upgrades se t to fly for the first time.

The second stage's Vikas engine will generate 190,000 pounds of thrust during it's 2-minute, 12-second firing on Thursday's mission, codenamed GSLV-F08. That's a 6 percent increase in thrust over Vikas engines flown on earlier GSLV missions.

Indian engineers intend to verify the High Thrust Vikas Engine's performance Thursday before introducing the upgrade to the four Vikas engines that power the GSLV Mk.2's strap-on boosters.

The second stage will also employ electromechanical actuators for the first time, replacing hydraulic systems used on past missions. The technology change will make the rocket more reliable, Indian officials said.

The GSLV Mk.2's core stage and boosters will produce nearly 1.8 million pounds of thrust at peak power, steering the rocket downrange from Sriharikota to the east-southeast over the Bay of Bengal.

The rocket's boosters and center stage will fire for around two-and-a-half minutes, propelling the vehicle to an altitude of around 235,000 feet, or 72 kilometers. The second stage's Vikas engine will ignite and the GSLV Mk.2's lower section -- comprising the core stage and boosters -- will jettison in one piece.

The rocket's metallic 11.1-foot (3.4-meter) nose cone will fall away in a clamshell-like fashion at T+plus 3 minutes, 45 seconds, during the second stage burn.

Ignition of the third stage's hydrogen-fueled engine is planned at T+plus 4 minutes, 46 minutes, for a firing scheduled to last nearly 13 minutes.

In another first, the upper stage will be programmed to fire a few seconds longer than on past missions to deplete the engine's liquid oxygen supply, giving the GSAT 6A satellite an extra bit of energy toward its high-altitude orbit.

Separation of the GSAT 6A satellite from the GSLV launcher is expected at T+plus 17 minutes, 46 seconds. Officials expect the spacecraft to reach an egg-shaped orbit ranging in altitude between 105 miles (170 kilometers) and 22,353 miles (35,975 kilometers), with a track tilted 20.6 degrees to the equator.

GSAT 6A's on-board engine will circularize its orbit over the equator, parking at an altitude wh ere the satellite's velocity will match the rate of Earth's rotation.

Geostationary orbits are typically used by communications satellites, and GSAT 6A will operate from a position at 83 degrees east longitude, giving the craft's S-band beams coverage over India.

GSAT 6A will unfurl a 20-foot (6-meter) S-band antenna after launch. The new satellite's design is similar to the GSAT 6 telecom craft successfully launched by a GSLV Mk.2 rocket in 2015.

ISRO says the two satellites are designed for mobile communications services.

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Трансляция пуска на канале Doordarshan National

youtube.com/watch?v=KzERHkm_Ld8

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https://www.isro.gov.in/update/29-mar-2018/propellant-filling-operations-of-cryo-stage-are-under-progress

Mar 29, 2018

Propellant filling operations of cryo stage are under progress

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http://spaceflight101.com/gslv-gsat-6a/upgraded-gslv-to-lift-gsat-6a/

Indian GSLV to Introduce First Incremental Engine Upgrade on GSAT-6A Launch
March 28, 2018

GSLV Rolls out for March 29 Liftoff – Photo: ISRO

India is gearing up for the country's second space launch of the year, targeting Thursday to send a Geosynchronous Satellite Launch Vehicle toward a high-energy orbital destination with the GSAT-6A government- and military-use communications satellite. Sporting an upgraded engine on its second stage, GSLV Mk.II is set for launch at 11:26 UTC and will be in action for just under 18 minutes to send the ~2,140-Kilogram satellite into a standard Geostationary Transfer Orbit.

Спойлер

Thursday's launch will mark the 12th launch of India's GSLV Mk.I/II launch vehicle family, the sixth of the Mk.II variant with a home-grown Cryogenic Upper Stage and the fifth since the rocket's comeback mission in 2014 after a major design overhaul. All four GSLV missions since the 2014 return to flight have been successful and the Indian Space Research Organization hopes to keep up this reliability record on Thursday before GSLV will be tasked with the high-profile Chandrayaan-2 lunar exploration mission in October, involving a lunar orbiter, lander and a small rover.


GSAT-6A prepares for launch on GSLV F08 – Photo: ISRO

India began design efforts in the 1990s to create a launch vehicle capable of launching Geosynchronous satellites while re-using a large number of proven components fr om the country's Polar Satellite Launch Vehicle which lacked the performance of lifting a meaningful payload mass into a Geotransfer orbit. The result, GSLV Mk. I, comprised the large solid-fueled core stage of PSLV, four liquid-fueled boosters relying on the proven Vikas engine, a hypergolic second stage also powered by Vikas and a cryogenic third stage procured fr om Russia.

This version of GSLV flew five times between 2001 and 2007 – to mediocre success as only two of the missions reached their target orbit.

GSLV Mk.II with an Indian Cryogenic Upper Stage debuted in 2010 but failed to reach orbit due to a failure of the Fuel Boost Pump on India's indigenous cryogenic engine. Another GSLV failure in 2010 sent the rocket back to the drawing board for a top-to-bottom review to identify design deficiencies and create a vehicle capable of satisfying the reliability demands of assured access to Geostationary Orbit from Indian soil.


Photo: ISRO

Since its return in 2014 – implementing dozens of changes and reinforcements across the vehicle – GSLV has been flying successfully, lifting payloads between 2.0 and 2.2 metric tons into GTO. With reliability concerns finally alleviated, ISRO has shifted focus on extracting the most possible performance from the GSLV design through an incremental upgrade process that begins with Thursday's upcoming mission and will continue into 2019 to eventually improve the rocket's GTO payload capacity from 2.2 to up to 3.2 metric tons.

Thursday's GSLV launch introduces an upgraded version of the Vikas 4 engine serving on the rocket's second stage, known as the High Thrust Vikas Engine, HTVE.

Vikas goes back to a cooperation between the French Space Agency CNES and ISRO under which ISRO provided manpower for the development of the Viking 4 engine for the Ariane 2-4 launch vehicle fleet in exchange for licensing rights of the engine design for its own launch vehicle fleet.

>> GSLV Launch Vehicle Overview


GSLV GS2 Stage with upgraded HTVE Engine – Photo: ISRO

ISRO adapted the original Viking design for domestic production in India, qualified the engine for longer burn times than on the Ariane rocket and went through a gradual upgrade process to arrive at the Vikas 2 and 4 engines flying on PSLV, GSLV and LVM3 today. In 2016, the Liquid Propulsion Systems Center announced it had successfully performed a 20-second hot-fire test of an upgraded Vikas that would eventually become the HTVE – offering a thrust increase of six percent.

According to ISRO, the vacuum version of the HTVE flying on the GS2 stage on Thursday will generate a thrust of 846.8 Kilonewtons, up from 799kN for the Vikas 4B through raising its chamber pressure from 58 to 62 bar. Consequently, the engine will burn propellant at a rate of 298 Kilograms per second and reduce the burn time of the second stage by seven seconds.

Future performance upgrades planned on the GSLV rocket include the replacement of the Vikas 2 engines on the four L40 boosters with sea-level versions of the HTVE (planned for Chandrayaan-2) and the Cryogenic Upper Stage, currently flying in its CUS-12 variant with 12,800kg propellant capacity, will be upgraded to CUS-15 in 2018 or 2019. Additional performance will be gained through dry mass reduction in various areas of the launch vehicle.

The payload of Thursday's GSLV F08 mission is GSAT-6A, an advanced S-Band communications satellite built by ISRO to provide capacity for mobile communications for use by the government and India's armed forces. Joining the similar GSAT-6 launched in 2015, the satellite will provide capacity expansion and continuity of mobile communication services into the mid-2020s.


GSAT-6A – Photo: ISRO

Based on the I-2K satellite platform, GSAT-6A reportedly weighs in at 2,140 Kilograms and targets an orbital position of 83 degrees East, co-located with its sister craft. The satellite is aiming for an injection orbit of 170 by 35,975 Kilometers at an inclination of 20.63 degrees from wh ere it will conduct three large orbit raising maneuvers with a combined change in velocity of 1,656 meters per second to reach a spot in the Geostationary Belt.

The satellite's communications package consists of five 9 MHz C x S-Band transponders generating five S-Band downlink beams carrying communications from ground stations to mobile communications terminals while five 2.7 MHz S x C-Band transponders receive the uplink from mobile terminals and route it to a ground station hub. GSAT-6A hosts a six-meter Unfurlable S-Band antenna reflector, the largest such deployable launched by India to date; C-Band hub communications are handled through a conventional 0.8-meter antenna.

>> GSAT-6A Satellite Overview


Photo: ISRO

The 49-meter tall GSLV rocket was rolled from its assembly building to the Second Launch Pad at the Satish Dhawan Space Center last week to enter final launch preparations. A final Launch Readiness Review on Tuesday cleared the rocket to press into a 27-hour countdown operation Wednesday afternoon, starting with tanking activities on the rocket's four boosters and the GS2 second stage that employ storable propellants while the Cryogenic Upper Stage will receive its dose of Liquid Hydrogen and Liquid Oxygen later in the countdown.

GSLV will come to life five seconds prior to liftoff when its four boosters are commanded to ignite followed by the ignition of the S139 Core Stage to lift the 415-metric-ton rocket off the ground with a total thrust of 800 metric-ton-force.

Heading east across the Indian Ocean, GSLV's core stage will consume 138 metric tons of packed solid propellant over the course of a minute and 47 seconds. One of the peculiarities of GSLV is that its core stage burns shorter than the four L40 boosters clustered around it, coming with the drawback of having to drag the dead weight of the core along for another 45 seconds but eliminating the need for four separation events as the L40/GS1 assembly separates as a whole once the boosters shut down.

Each burning 42,700 Kilograms of UH25/NTO propellants with their Vikas engine, the four boosters will accelerate the vehicle to a speed of 2.4 Kilometers per second. Separation of GS1 occurs 73 Kilometers in altitude at T+2 minutes and 31 seconds with the GS2 stage firing up its HTVE moments before separation systems are initiated. Tasked with a 132.38-second burn, the 11.6-meter long second stage will accelerate the stack by another 2.5 Kilometers per second before the Cryogenic Upper Stage takes over.

>> Flight Profile


Mission Ground Track – Image: ISRO

GSLV will drop its 3.4-meter diameter payload fairing three minutes and 45 seconds into the flight when passing through 115 Kilometers in altitude wh ere aerodynamic forces can no-longer harm the satellite. Separation of the GS2 stage occurs at T+4 minutes and 45 seconds and will be followed one second later by the ignition of the CE-7.5 cryo engine on a long burn of 12 minutes and 45 seconds – tasked with increasing the rocket's speed by almost five Kilometers per second to an injection velocity of 9.7 km/s.

India's cryogenic stage begins its burn in high-thrust mode providing 9,500kgf of thrust before reducing thrust to 7,500kgf for the remainder of the burn. GSAT-6A is expected to separate from the 12.8-meter long CUS at T+17 minutes and 46.5 seconds, sailing off on a mission of at least ten years delivering strategic communications.

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