chief
Prime VIP
Bangalore, July 9
The Indian Space Research Organisation (ISRO) today claimed to have identified the reasons for the failure of its geosynchronous launch vehicle powered by an indigenous cryogenic upper stage (CUS) and said the next GSLV flight with an indigenous CUS was being planned within a year.
A press release issued by ISRO said stoppage of the fuel booster turbo pump (FBTP) had cut off the supply of liquid hydrogen to the main engine of the cryogenic upper stage (CUS). This resulted in the crash of the 49-metre tall rocket into the sea about five minutes after it was fired from the spaceport at Sriharikota in Andhra Pradesh on April 15.
The failure was a blow to the state-run ISRO as this was its maiden attempt to power the GSLV rocket with an indigenous CUS. ISRO said it had instituted a two-tier process to carry out an in-depth analysis of the flight performance of the rocket, identify the causes of its failure and recommend corrective measures.
The findings of the failure analysis committee consisting of experts in various fields were further verified by a national group of eminent experts.
According to ISRO, the initial conditions required for the start of the indigenous CUS were attained as expected and the CUS start sequence got initiated as planned at 294.06 seconds from lift-off.
The ignition of the CUS main engine and two steering engines were confirmed as normal, as shown in the vehicle acceleration and different parameters of CUS measured during the flight. Vehicle acceleration was comparable with that of earlier GSLV flights (fired with Russian cryogenic engines) up to 2.2 seconds from start of CUS. However, the thrust build up did not progress as expected due to non-availability of liquid hydrogen (LH2) supply to the thrust chamber of the main engine. According to ISRO, the problem was caused by the anomalous stopping of the fuel booster turbo pump. The start-up of FBTP was normal. It reached a maximum speed of 34,800 rpm. But the speed of FBTP started dipping less than a second after the start of the CUS (0.9 seconds) and it stopped completely within the next 0.6 seconds.
Two plausible reasons were identified for the failure of FBTP. The first was gripping at one of the seal location and seizure of rotor and; second, rupture of turbine casing due to excessive pressure rise and thermal stresses. ISRO will carry out a series of ground tests to confirm the findings.
The Indian Space Research Organisation (ISRO) today claimed to have identified the reasons for the failure of its geosynchronous launch vehicle powered by an indigenous cryogenic upper stage (CUS) and said the next GSLV flight with an indigenous CUS was being planned within a year.
A press release issued by ISRO said stoppage of the fuel booster turbo pump (FBTP) had cut off the supply of liquid hydrogen to the main engine of the cryogenic upper stage (CUS). This resulted in the crash of the 49-metre tall rocket into the sea about five minutes after it was fired from the spaceport at Sriharikota in Andhra Pradesh on April 15.
The failure was a blow to the state-run ISRO as this was its maiden attempt to power the GSLV rocket with an indigenous CUS. ISRO said it had instituted a two-tier process to carry out an in-depth analysis of the flight performance of the rocket, identify the causes of its failure and recommend corrective measures.
The findings of the failure analysis committee consisting of experts in various fields were further verified by a national group of eminent experts.
According to ISRO, the initial conditions required for the start of the indigenous CUS were attained as expected and the CUS start sequence got initiated as planned at 294.06 seconds from lift-off.
The ignition of the CUS main engine and two steering engines were confirmed as normal, as shown in the vehicle acceleration and different parameters of CUS measured during the flight. Vehicle acceleration was comparable with that of earlier GSLV flights (fired with Russian cryogenic engines) up to 2.2 seconds from start of CUS. However, the thrust build up did not progress as expected due to non-availability of liquid hydrogen (LH2) supply to the thrust chamber of the main engine. According to ISRO, the problem was caused by the anomalous stopping of the fuel booster turbo pump. The start-up of FBTP was normal. It reached a maximum speed of 34,800 rpm. But the speed of FBTP started dipping less than a second after the start of the CUS (0.9 seconds) and it stopped completely within the next 0.6 seconds.
Two plausible reasons were identified for the failure of FBTP. The first was gripping at one of the seal location and seizure of rotor and; second, rupture of turbine casing due to excessive pressure rise and thermal stresses. ISRO will carry out a series of ground tests to confirm the findings.
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