After 39 consecutive successful launches, the Indian Space Research Organisation had almost made it appear that launching satellites was indeed child’s play when it used its workhorse rocket, the Polar Satellite Launch Vehicle. But the PSLV, which has been placing satellites in their respective orbits for the past 24 years, faced a setback on August 31. The PSLV-C39 rocket carrying the eighth satellite of the Indian Regional Navigation Satellite System (IRNSS) had a normal lift-off and flight events but ended in an unsuccessful mission. The heat-shield failed to separate, resulting in the satellite separation occurring within the shield. This is just the second instance when the PSLV has had an unsuccessful mission in all of its 41 launches; the first setback was back in 1993. Over the years, the PSLV has played a pivotal role in ISRO’s programme, and this February it set a world record by launching 104 satellites in one go. With such an enviable track record, the failure of the mission this time almost comes as a surprise. This is especially so as the lift-off and the stage separation of the first and second stages, which are the most challenging parts of the mission, went off smoothly. In comparison, the heat-shield separation is a relatively minor operation which takes place once the rocket crosses an altitude of 100-110 km, and the temperature in the absence of the heat-shield will no longer damage the satellite. The failed mission serves as a reminder that utmost care and scrutiny are required before every single launch. While scientists are working to identify the cause of the anomaly in the heat-shield separation event, the failed mission should have no impact on future launches involving the vehicle.
The failure of the mission is particularly disheartening as the IRNSS-1H satellite was jointly assembled and tested by ISRO and a Bengaluru-based private company, the first time a single private company, rather than a consortium, was involved in building a satellite. The satellite was in no way to blame for the failure of the mission. The space organisation has thrown open its doors to private companies to build as many as 18 spacecraft a year beginning mid or end-2018. The IRNSS-1H satellite was launched as a replacement for the IRNSS-1A satellite, which became inoperational in terms of surveillance following the failure of all three atomic clocks. As only six of the seven satellites are operational, there are gaps in the navigation data sent by the IRNSS. With the failure of this mission, India will have to wait for some more time before the next mission to send a replacement for the IRNSS-1A satellite is ready. The IRNSS was created so that the country would not need to rely on American-based GPS data — the encrypted, accurate positioning and navigation information provided by the system will make Indian military operations self-reliant.
ISRO suspects pyro elements failed to separate rocket’s heat shield
The Indian space agency is strongly suspecting the failure of pyro elements for the non-separation of the heat shield of its rocket Polar Satellite Launch Vehicle’s (PSLV) XL variant on Aug 31, said a senior official.
As a result of the heat shield not separating the 1,425 kg navigation satellite IRNSS-1H got stuck inside it resulting in the failure of the around Rs 250 crore mission.
Normally the heat shield will be separated soon after the rocket crosses the earth’s atmosphere.
According to K. Sivan, Director, Vikram Sarabhai Space Centre (VSSC), all the systems during the rocket’s flight worked well while the only suspect place is the pyro elements.
The VSSC is part of the Indian Space Research Organisation (ISRO).
“Tests are going on to find out the reasons for the failure of heat shield separation. Each test takes around 72 hours,” Sivan told IANS.
One fortunate aspect of the failure is that ISRO has all the flight data as the rocket was not lost during its one way journey.
Sivan said the heat shield would separate after on-board computers give the command to ignite the explosives. The explosives would then ignite and explode to separate the two parts of the heat shield joined by bolts.
Quelle: The Statesman