GSAT-6A Launch by GSLV F08

Why in news?

The GSLV F08 launched the GSAT 6A communication satellite into its orbit, from the Satish Dhawan Space Centre at Sriharikota.

What is GSAT-6A for?

• GSAT-6A, similar to its predecessor GSAT-6, is a high power S-band communication satellite.
• It has a mission life of around 10 years.
• The satellite has a six-metre wide antenna that would unfurl once it is in space.
• The antenna, meant for S-band communication, is 3 times broader than those generally used in ISRO satellite.
• This feature facilitates mobile communication for the country through handheld ground terminals.
• The smaller antenna in other communication satellites requires larger ground stations.
• The GSAT-6A is intended to provide communication services through multibeam coverage.
• The satellite would also provide services to the Indian Armed Forces.
• The GSAT-6A was successfully placed in GTO (Geo-stationary Transfer Orbit).
• Soon after separation from GSLV, the two solar arrays of GSAT-6A were automatically deployed in quick succession.
• The Master Control Facility (MCF) at Hassan in Karnataka assumed control of the satellite.

What is the significance?

• Launch - The launch took ISRO a step towards realising its second Moon mission Chandrayaan 2 planned for October 2018.
• The launch was the 12th satellite launched on board the GSLV rocket.
• This is the fifth consecutive success for a GSLV equipped with an indigenously developed Cryogenic Upper Stage engine.
• GSLV - The GSLV F08 is an improved and a fully operational version of ISRO’s heavy-lift GSLV Mk II rocket series.
• The GSLV, specifically the GSLV F10, is the designated rocket to fly India’s second mission to the Moon, the Chandrayaan 2.
• In the absence of heavy-lift rocket technology, India has been relying on France for launching its communication satellites.

• Vikas Engine - Vikas engine powered the rocket’s second stage.
• The performance of the vehicle is enhanced with an improved Vikas engine.
• The improved engine has increased the thrust by 6%, thereby enhancing payload capability of the vehicle by 50%.
• The second stage also had electromechanical actuation system replacing electrohydraulic actuation system.
• This is to enhance the reliability of the rocket.
• These improvements to the vehicle would be incorporated into GSLV’s future missions, including Chandrayaan-2.

Why is the cryogenic stage significant?

• The indigenous cryogenic stage on the GSLV is the third stage, and uses liquid hydrogen as fuel and liquid oxygen as oxidiser.
• Challenge - Cryogenic engine uses propellants at extremely low temperatures.
• The resultant and associated thermal and structural problems make cryogenic stage a very complex system.
• Benefits - Cryogenic engines provides more thrust for every kg of propellant it burns.
• It is a highly efficient rocket stage as the efficiency is better when compared to solid and earth-storable liquid propellant stages.
• Cryogenic engines also keep fuel loads relatively low.
• GSLV - Cryogenic engines provide unprecedented thrust to GSLV rockets in their final stages.
• Nearly 50% of the power for GSLV rockets as they push into space comes from the cryogenic stage.

How did the cryogenic technology evolve in India?

• India had first ventured on the path of obtaining cryogenic technology in 1992.
• It had a two-pronged strategy of purchasing cryogenic engines from Russia, and acquiring the technology from the US.
• But following the 1998 nuclear tests and the sanctions that followed, the US denied India cryogenic technology.
• ISRO used 7 cryogenic engines sold by Russia for the early phase of its GSLV programme that began in 2001.
• Parallelly, India ventured into developing an indigenous technology.
• GSLV launches with Russian engines, including early operational flights, had mixed results, with only 2 flights going perfectly to plan.
• The first GSLV flight with an indigenous cryogenic upper stage failed on April 15, 2010.
• But India is now among 6 nations, along with the US, Russia, France, Japan and China, to possess cryogenic engine technology.

What lies ahead?

• ISRO is still in the process of developing a fully operational GSLV Mk III rocket.
• This can carry satellites weighing more than 4 tonnes to space.
• The cryogenic upper stage in the GSLV Mk III rocket uses the C25 engine.
• This is an improvement on C20 cryogenic engines used in the GSLV Mk II rockets.
• A GSLV Mk III D2 rocket is scheduled to fly a GSAT 29 communication satellite to space in its second mission soon in the year.

Source: Indian Express