CHENNAI: IT took a while for the formal announcement of the failure of PSLV C-39 mission to come. A day after the debacle, the first in 24 years, it was reliably learnt that the scientists knew within less than four minutes of flight it was coming.
The mission director authorised the vehicle director for launch, who in turn authorised the automatic launch sequence (ALS) programme for launch of PSLV-C39/IRNSS-1H Satellite mission at 6:47 pm from the second launch pad of Satish Dhawan Space Centre SHAR, Sriharikota. The rocket lifted-off at 6.59 pm, and the heat shield, which played the spoilsport, was supposed to have separated at 7.03.23.
Simply put, the heat shield command in the ALS snapped. A careful analysis of the footage of previous PSLV launches showed that heat shield should have separated even before the second stage separation.
A close look at the video of PSLV C-37, which successfully placed 104 satellites in one go shattering the world record in February this year, throws light on the actual sequence of events, and provides clues on the sequence of events after the launch.
Sources told Expressthat the use of the heat shield ends once the rocket reaches above 100 km where the heat generated by friction with the atmosphere reduces substantially. What happened in the case of PSLV C-39 was that the rocket that lifted-off with a velocity of 452 metre per second gained speed of 3,705.42 metre per second under four minutes of flight, reaching an altitude of 115 km. Here, the heat shield was programmed for separation, which didn’t happen.
The rocket continued to travel, and performed all other functions normally, notching up a top speed of 9,638.79 metre per second and achieving the desired altitude of 507 km. But the satellite remained trapped inside the heat shield. ISRO officials claim there is no real damage to the reputation of India’s workhorse PSLV in international arena as the failure was due to an isolated technical glitch. However, industry experts say the agency should quickly re-establish the faith, which probably got a beating with Thursday’s ‘elementary’ failure.