GSAT-12 = PSLV-C17 (XL)- 15.07.11 15:18 ЛМВ

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http://economictimes.indiatimes.com/news/politics/nation/india-notches-another-space-success/articleshow/9238674.cms

15 Jul, 2011, 10.15PM IST,IANS
India notches another space success[/size]

SRIHARIKOTA (Andhra Pradesh): India notched another milestone in its space programme on Friday evening when it successfully launched a heavy-duty rocket that placed a major communications satellite in space.

A beaming Indian Space Research Organisation (ISRO) chief K Radhakrishnan told reporters after the 4.48 p.m. launch Friday that the mission was a success.

"It is a tricky mission. I am extremely happy to state that the PSLV (Polar Satellite Launch Vehicle)-C17 GSAT-12 mission is successful. The satellite was launched in the intended orbit," he said at the launch site here, 80 km north of Tamil Nadu's capital Chennai.

V Narayanasamy, Minister of State in the Prime Minister's Office, said: "I am extremely happy (at the successful launch). I am coming here for the second time, and it is a second successful launch. On behalf of the prime minister, UPA chairperson Sonia Gandhi, I congratulate the ISRO scientists for the wonderful performance."

The PSLV blasted off successfully at 4.48 p.m., carrying the 1,410 kg GSAT-12 satellite from the spaceport here. The satellite has a life span of about seven years.

With this, India added 12 more communication transponders to its space-based network.

The launch took place under a cloudy sky, with the Rs 95 crore rocket PSLV-C17, measuring 44 metres in height and weighing 320 tonnes, soaring off into space with a roar. It ferried the Rs 105 crore GSAT-12 having 12 extended C-band transponders, automatic receivers and transmitters for communication and broadcast of signals.

With a rich orange flame at its rear, the one-way ticket rocket left behind a huge tail of white plume as it rose into the sky to the cheers of ISRO scientists and media team assembled at the launch centre. People perched atop of the nearby buildings too happily applauded as PSLV-C17 went up.

Around 20 minutes after the blast off, the rocket achieved its mission by placing the latest Indian communication satellite in the intended sub geosynchronous transfer orbit (sub GTO).

The GTO is an intermediate orbit from where normally communication satellites will be moved to its final geosynchronous orbit by firing the on-board motors. Radhakrishnan said the rocket's navigation systems were powered by Indian-made advanced Vikram processors.

"We needed to make modifications in the rocket's navigational software for this mission," Radhakrishnan said.

The GSAT-12 carries around 851 kg of fuel on-board to fire the motors. (A geosynchronous orbit is one directly above the earths' equator. For an observer from the earth a satellite in geosynchronous orbit will seem motionless, stationary at one point in the sky).

The rocket placed the satellite in sub GTO with a 284 km perigee (nearest point to earth) and 22,020 km apogee (farthest point from the earth). The satellite will be raised to 36,000 km apogee from 22,020 km over the next two days. The satellite will be useful for various communication services like tele-education, tele-medicine and for village resource centres, Radhakrishnan said.

The GSAT-12 satellite is also expected to serve the Very Small Aperture Terminal (V-SAT) sector. VSATs are used to transmit data like point of sale transactions or to provide satellite internet access. T.K. Alex, director of ISRO Satellite Centre , said the initial operations after putting the satellite in orbit went of smoothly.

"The solar panels were deployed and are generating power. The satellite orbit will be raised from 22,020 km apogee to 36,000 km apogee tomorrow and day after. All the 12 transponders in the satellite will be tested by the end of this month," Alex said.

He said there will be sufficient fuel left in GSAT-12 after carrying raising its orbit to 36,000 km apogee so that it can be in operation for seven years. Immediately after satellite ejection, ISRO with its network of ground stations monitored its health.
The satellite will augment transponder capacity of Indian National Satellite (Insat) system which at present comprises of eight satellites, Insat-2E, Insat-3A, Insat-3C, Insat-3E, Insat-4A, Insat-4B (working at 50 percent capacity) Insat-4CR and GSAT-8 providing 175 transponders in the S, C, extend C and Ku bands.

The Indian space agency has leased 86 more transponders from various foreign satellites. It is estimated there is an unmet demand for 170 transponders.

ISRO used its third PSLV rocket variant, PSLV-XL, with longer strap-on motors with higher fuel capacity, to put the latest communication satellite in the space.

The other two rocket variants are the PSLV standard with 11.3 metres six strap-on motors and the PSLV Core Alone (CA) rocket without the six strap-on motors.

The PSLV-C17 that went up Friday had 13.5 metres long strap-on motors carrying 12 tonnes of solid fuel than the normal strap-on motors measuring 11.3 metres with nine-tonne fuel capacity.

This is the second time ISRO has launched a rocket with this specification. The earlier one was for the Chandrayaan moon mission.

This is also only the second time ISRO is using a PSLV rocket for launching a satellite to be finally placed in geostationary orbit. The first satellite was Kalpana-1 (originally named as Metsat), a meteorological satellite launched in 2002.

The PSLV has an excellent success record since 1994, launching many Indian and foreign satellites.

ISRO officials told IANS that a remote sensing satellite - Megha-Tropiques - is being planned for launch later this year.[/size]

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http://economictimes.indiatimes.com/news/news-by-industry/et-cetera/Indian-communication-satellite-raised-to-near-its-orbit/articleshow/9269306.cms

18 Jul, 2011, 01.31PM IST,IANS
Indian communication satellite raised to near its orbit[/size]

CHENNAI: The Indian communication satellite GSAT-12 is now very near to its ultimate geo-stationary orbit at 36,000-km apogee, or farthest point from Earth, space agency ISRO said Monday.

Indian Space Research Organisation (ISRO) has successfully raised the satellite's orbit to 35,721 km apogee and 10,074 km perigee (closet point from Earth) since its launch July 15.

"All the satellite sub-systems are functioning well. The orbit raising manoeuvres are progressing satisfactorily," S. Satish, ISRO director, publications and public relations, told IANS on phone from Bangalore.

He said a total of three orbit raising operations have been carried out since the July 15 blast-off of teh rocket carrying the GSAT-12.

The Rs.105 crore GSAT-12 satellite with 12 extended C-band transponders - automatic receivers and transmitters for communication and broadcast of signals - was launched by ISRO's lighter rocket polar satellite launch vehicle (PSLV) from the space port at Sriharikota, around 80 km from Chennai, July 15 evening.

For an observer from earth, a satellite in geosynchronous orbit will seem motionless, stationary at one point in the sky.

The GSAT-12 carries around 851 kg of fuel on-board to fire the motors. Its lift-off mass was 1,410 kg.

Soon after the launch, T.K. Alex, director of ISRO Satellite Centre, said there will be sufficient fuel left in GSAT-12 after raising its orbit to 36,000 km apogee so that it can be in operation for seven years.[/size]

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http://www.thehindu.com/news/national/article2260309.ece

CHENNAI,  July 19, 2011

GSAT-12 reaches its home in a circular geo-synchronous orbit[/size]
T. S. Subramanian

 India's communication satellite GSAT-12, put in orbit on July 15, reached its home in a circular geo-synchronous orbit at an altitude of 36,000 km on Tuesday. The Polar Satellite Launch Vehicle (PSLV-C17) of the Indian Space Research Organisation (ISRO), which lifted off from the space station at Sriharikota on July 15, 2011, put the 1,410 kg GSAT-12 in a sub geo-synchronous transfer orbit (sub-GTO) with an apogee of 21,020 km and a perigee of 284 km.

Challenging operation

 After the satellite was put in a sub-GTO, the liquid apogee motor (LAM) on board was fired once each day from July 16-19 to circularise the orbit at an altitude of 36,000 km. On July 16 and 17, commands were given from the Master Control Facility (MCF) at Hassan in Karnataka to the LAM to take the satellite's apogee from 21,020 km to 36,000 km when the satellite was at its perigee. Similarly, the commands to the LAM to fire to take the perigee from 284 km to 36,000 km were given on July 18 and 19 when the satellite was at its apogee. "Thus, it was a challenging operation," said an ISRO official.

 "But all operations went off well. The sub-systems on board the satellite are functioning normally. The satellite has now made it to its final, circular geo-synchronous orbit of 36,000 km," he added.

 The LAM will be fired again on Wednesday for final trimming of the satellite's orbit.

 With 12 extended C-band transponders, the satellite will be useful in tele-education, tele-medicine, disaster management support, telephone services and so on. [/size]

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http://www.isro.org/pressrelease/scripts/pressreleasein.aspx?Jul21_2011

July 21, 2011    
GSAT-12 Communication Satellite placed in Geosynchronous Orbit[/size]

The GSAT-12 Communication Satellite, launched onboard Polar Satellite Launch Vehicle (PSLV-C17), has been successfully placed in Geosynchronous Orbit with a perigee of 35,684 km, apogee of 35,715 km and an orbital inclination of 0.17 deg with respect to the equatorial plane.

It may be recalled that on July 15, 2011, PSLV-C17 had injected GSAT-12 into an elliptical transfer orbit of 281 km perigee and 21,027 km apogee, and orbital inclination of 17.9 deg. The critical manoeuvres to raise GSAT-12 Satellite into Geosynchronous Orbit were performed by firing the 440 Newton Liquid Apogee Motor of GSAT-12 Satellite for about 80 minutes in five spells during July 16-20, 2011.

The Communication antenna onboard the satellite was deployed successfully today (July 21, 2011) at 15:30 hrs (IST) and the Satellite is in its final orbital configuration, pointing towards Earth.

GSAT-12 is now located at 63 deg East longitude. The Satellite would be moved to reach its designated longitude of 83 degree East within the next 16 days (at the rate of one degree per day). The GSAT-12 Satellite will be co-located with INSAT-2E and INSAT-4A Satellites.

After parking the Satellite at this location, the Communication Transponders are planned to be switched on by August 5, 2011, followed by In-Orbit Testing. The GSAT-12 Satellite is in good health and is in continuous radio-visibility from ISROs Master Control Facility, Hassan.[/size]

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http://forum.nasaspaceflight.com/index.php?topic=25379.msg783408#msg783408

input~2 пишет:

Well, Stratcom has finally published to-day new data for object 37747/11034B (GSAT-12) (last data was dated July 16..):

GSAT-12 was observed in 35,686 x 35,717 km inclined 0.17° yesterday July 25 at 1738UTC passing 73.2°E and drifting East with a drift rate of 1.1°/day
(I would then have expected it to be at 68° on July 21 not 63° )