Two objects now being tracked.42928 51A 163 x 6539 km x 19.15 deg42929 51B 175 x 6515 km x 19.15 degToo early to speculate usefully on what's going on with that.
1 tonne of extra weight doomed PSLV missionQuoteThe PSLV-C39 rocket, which failed to launch the IRNSS 1H satellite on Thursday, was dragged down by at least one tonne of extra weight from the unseparated heat shield after the second stage, its velocity reduced by one kilometre per second. This greatly reduced the altitude it was to reach for a successful mission, say scientists privy to the project.
The PSLV-C39 rocket, which failed to launch the IRNSS 1H satellite on Thursday, was dragged down by at least one tonne of extra weight from the unseparated heat shield after the second stage, its velocity reduced by one kilometre per second. This greatly reduced the altitude it was to reach for a successful mission, say scientists privy to the project.
The Failure Analysis Committee, headed by VSSC Director K.Sivan, is poring through the flight data of the mission in a bid to understand what went wrong. Dr.Sivan toldThe Hindu that a simulation exercise would be carried out to zero in on the exact reason. “We are on track and hope to reach a conclusion within a week,” he said.
Based on the initial inference, informed sources at ISRO said the command for separation had gone through but failed to trigger the mechanical process that pops open the heat shield. They said the investigations were likely to centre on the electrically-initiated pyro devices that initiate the sequence of separation.
What is intriguing for scientists is that the pyro device which probably malfunctioned, is based on an electro-mechanical process, one that is far less complex than thousands of other components in the rocket.
Isro chairman AS Kiran Kumar on Saturday firmly denied that the PSLV-C39 rocket carrying eighth navigation satellite IRNSS-1H failed on Thursday as it was carrying one-tonne extra load. A report in TOI on Saturday had stated that "the PSLVC39 rocket, which failed to launch the IRNSS-IH, was dragged down by at least onetonne extra weight". The report stated that this was more than the design permitted.
Speaking to TOI on Saturday prior to making a presentation at the Nehru Centre in Mumbai, the Isro chief said: "The report is incorrect and the rocket was not carrying any extra load." He said the heat shield added additional weight to the launch vehicle as it failed to get detached at the second stage and went along till the fourth stage separation point. "It was not because Isro put any additional weight prior to the launch," he said.
He added that a portion of the rocket with the satellite enclosed in the heat shield was currently orbiting 163km x 6,600 km and was being tracked by the multi-object tracking radar at Satish Dhawan Space Centre, Sriharikota. "It is expected to remain this way for another 25 days,'' he said. Kiran Kumar said a failure analysis committee was being formed to study the setback.
Dr K Sivan, director of Thiruvananthapuram-based Vikram Sarabhai Space Centre (VSSC), said, "Launch failure will not affect future missions as they will go as planned. But corrective measures will be taken in future for all types of vehicles as the heat shield separation mechanism is similar in all launchers."
The use of the term "heat shield" for the component that failed on this launch is incorrect and confusing. A heat shield protects spacecraft during reentry, a payload shroud protects them during launch. They are physically very different.
All propellant aboard PSLV fourth stage and IRNSS-1H has been vented. Accurate reentry location determination would be possible a week in advance.
QuoteAll propellant aboard PSLV fourth stage and IRNSS-1H has been vented. Accurate reentry location determination would be possible a week in advance.https://www.reddit.com/r/ISRO/comments/6y48ax/all_propellant_aboard_pslv_fourth_stage_and/
Decay dates from SatEvo:C: late October 2017B (PSLV DEB): around Christmas 2017A (IRNSS 1H/PSLV): early July 2018
“we have depleted all the propellant through the gap in the heat shield and the fourth stage.” Dr K Sivan Director VSSCAs per reddit above.