Raumfahrt - ISRO loses contact with GSAT-6A, efforts are on to re-establish communication -Update



After the GSAT-6A satellite launch on March 29, ISRO had been a little quiet on further information about its progress. It confirmed on Sunday that it had lost contact with the satellite and were doing their best to fix the communication channels.

The Indian Space Research Organisation said in a statement that on March 31, the satellites second orbit raising operation was successfully carried out by the Liquid Apogee Motor (LAM) Engine firing for about 53 minutes.


The satellite was then on course for the third and final firing with a normal operating configuration, when communication was suddenly lost.


Suspicions arose when ISRO didnt update any information regarding its second orbit-raising operation on March 31. The update before that spoke of the success of the first orbit raising operation on March 30.

This was the ISRO Chairman K Sivans first mission since he took the helm of the space agency in January 2018.

Around 400 scientists and engineers were called in to help with the launch at the Satish Dhawan Space Center, located on the coast near Chennai.





  • Talking about the GSAT-6A, former ISRO Chairman Kiran Kumar said that the communication satellite carries one of the largest antennas ever built by ISRO. Not only it has a diameter of 6 meters but also opens up like an umbrella once the satellite is in orbit
  • GSAT-6A satellite weighs 2066 kg and costs around Rs 270 crore
  • The big size gives it more power and ensures that its signals can be received through smaller and handheld devices whether for data, video or voice
  • GSAT-6A is the twin of GSAT-6 which was launched in 2015
  • The two rockets in tandem will provide signals that that would permit a two-way exchange of data even from very remote locations where mobile connectivity is still limited -- which makes it very useful for the armed forces 



ISRO Chairman K Sivan had earlier told the agency that the GSAT-6A would be followed by the launch of a navigation satellite, in the next fiscal.

In the Union budget for 2018-19, the Department of Space has been tasked to make ready for launch three earth observation spacecraft, four Polar Satellite Launch Vehicle (PSLV) flights, and one each of Geosynchronous Satellite Launch Vehicle Mk II and Mk III.



Update: 2.04.2018


GSAT-6A not out of control, trying to re-establish contact with satellite, says ISRO Chairman K Sivan

On April 1st, the Indian Space Research Organisation (ISRO) had confirmed that it has lost all contact with the country’s most powerful communication satellite, the GSAT-6A, in less than 48 hours after it was launched on Thursday, 29th March. 

In conversation with Times of India, ISRO Chairman Kailasavadivoo Sivan said, “After the successful launch of Gsat-6A from Sriharikota on Thursday, ISRO was supposed to perform three orbit-raising manoeuvres to take the satellite from the launch orbit to the designated orbit (geo stationary orbit that is at the altitude of 36,000 km). The first manoeuvre was performed successfully on Thursday. The second orbit-raising exercise was performed on Saturday. As the ISRO ground station was gearing up for the third manoeuvre, the communication link with the satellite snapped.”

ISRO had launched the home-made GSAT-6A communication satellite using the Geosynchronous Satellite Launch Vehicle (GSLV-F08) from Satish Dhawan Space Centre (SDSC) in Sriharikota on Thursday, 29th March. The high power S-band communication satellite has a lifespan of around 10 years, and was launched from the second launch pad at the Sriharikota rocket port at 4.56 pm.

Sivan added, “Our team is trying to re-establish the communication link with the satellite. Though the delinking of signal from a satellite is a common phenomenon, this time the signal delinking is happening for a longer duration. Even if the satellite's primary power has failed, we can use the back-up power like solar power if we are able to re-establish the contact with it.”

This was the first mission for Sivan, who assumed charge of the space agency in January. In August last year, India's mission to launch its backup navigation satellite IRNSS-1H on board PSLV-C39 ended in a failure after a technical fault on the final leg following a perfect launch. ISRO had then said the heat shield had not separated on the final leg of the launch sequence and, as a result, IRNSS-1H had got stuck in the fourth stage of the rocket. 

The 2,140-kg GSAT-6A rode piggyback on ISRO's powerful geosynchronous rocket (GSLV-F08) fitted with indigenous cryogenic engine at the third stage and was put into orbit successfully after the launch in what was described by a senior ISRO official as a "magnificent mission".

The launch of GSLV-F08 marked the 12th flight of Geosynchronous Satellite Launch Vehicle GSLV-F08 and sixth flight with indigenous Cryogenic upper stage. GSAT-6A is similar to GSAT-6, a high power S-band communication satellite built on I-2K satellite bus with a mission life of about ten years.

GSLV-F08, weighing 415.6 tonnes with a height of 49.1 metre also comes with notable improvements like induction of High Thrust Vikas Engine, electromechanical actuation system in place of electro-hydraulic actuation system.

Quelle: DNA


Update: 3.04.2018


India trying to reconnect with most powerful communications satellite: ISRO

NEW DELHI -India’s space agency said on Monday it was trying to re-establish a link with its most powerful communication satellite that went missing over the weekend, in a setback for its space ambitions.


Indian Space Research Organisation (ISRO) said the link with the satellite was lost in the third and final stage of its launch, but it did not specify the possible cause of the snag.

“Efforts are underway to establish the link with the satellite,” ISRO said on its website.


The satellite was launched on Thursday through an indigenously developed launch vehicle.

The GSAT-6A is an advanced mobile communications satellite with a six-meter wide antenna, the biggest used by an ISRO communication satellite.

Once located, the agency should be able to command and take the satellite to its final orbit.

If not, the satellite would come down and burn out like any other, an agency official said.


The satellite would enable advanced mobile communications, the space agency said, including for the military.

India is seeking a larger share of the more than $300 billion global space industry as Prime Minister Narendra Modi seeks to project it as a global low-cost provider of services in space.



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