Extra Weight Of Heat Shield Dragged Down IRNSS-1H Navigation Satellite

| September 2 , 2017 , 11:26 IST

As the IRNSS-IH navigation satellite launched failed on Thursday, reports are saying that the PSLV-C39 rocket, which was tasked to launch it into the orbit, was dragged down due to at least one-tonne extra weight in the rocket.

The extra drag reduced the speed of the rocket up to a critical one kilometre per second, which inevitably resulted in failure of reaching the optimum altitude.

"The launch vehicle was carrying at least one tonne more than its design permitted it, as the heat shield did not separate. This affected its velocity. For example, it should have attained a velocity of 9.5km per second at the end of it but attained only 8.5km per second," said Former ISRO Satellite Centre director SK Shivakumar.

The heat shields protect the inside of the rocket from heat generated by the friction of air against the rocket's body during the takeoff.

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Addressing the press conference after the launch failure, the chairman Kiran Kumar said,  "The rocket heat shield didn't separate. The satellite is inside the heat shield."

The shield is expected to separate from the satellite once it is placed into orbit. However, the heat shield did not separate from the satellite even after receiving the command.

As a result, the satellite was dragged back down to earth after the 114th second.

Shivakumar said, "I cannot accurately say by how much it missed the desired altitude. It was supposed to have an apogee (farthest point from Earth) of 20,650km but managed only 6,000-odd km."

The ISRO chairman has said, "Thursday's failure would not affect future missions as there was no structure or design flaw. There has been a snag that resulted in the heat shield not separating... what exactly caused that needs to be found out. A team of experts has begun the examination."