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
