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Experts say Chandrayaan-2 delay was pre-emptive, mission not a failure

They say that such delays are common globally; no clarity yet on new launch date

T E Narasimhan  |  Sriharikota 

Chandrayaan 2, Isro, Moon mission

The launch of India’s second moon mission, Chandrayaan-2, was called off on Monday, after Indian Space Research Orgamisation (Isro) identified a technical snag in the country's heaviest rocket, GSLV Mk-III, nicknamed Baahubali. While the last-minute call-off by Isro spurred discussions on the GSLV's capability, considering that this will be the launch vehicle for India's Human Space Programme, it is important to note that Chandrayaan-2 is not a failed launch. The launch was delayed in order to avoid failure, and that such things are common globally, say experts. While excitement was skyrocketing among the 7,000 people (excluding Isro officials), including the President of India, who gathered to witness India's most ambitious space mission Chandrayaan-2, the countdown clock of GSLV MkIII stopped only 56:24 minutes before the lift-off, which was scheduled at 02:51 hours on July 15. “The countdown was stopped. Launch was postponed due to a technical snag (during the customary pre-flight checks). It is not possible to meet the launch within the window," the Mission Director said, adding the new schedule would be announced later. As people started walking back disappointed, Isro tweeted: “A technical snag was observed in the launch vehicle system one hour before the launch. As a measure of abundant precaution, #Chandrayaan2 launch has been called off for today.” Isro officials pointed that another lift-off opportunity is available tomorrow (July 16), but launch windows have to meet several technical criteria. It would take at least 10 days for the entire process, so it could even take weeks or months for a new date for the mission, which has been pending since 2018. Calls and messages to K Sivan, chairman, Isro were not responded. Isro officials said the snag was in the cryogenic or last stage of the rocket before it separates. An hour before lift-off, Isro announced that the filling of liquid hydrogen fuel had been completed, but experts pointed out that the snag could have been mechanical, and did not rule out the possibility of fuel leakage. "While it is speculative to comment on the nature of the snag, the GSLV on-board systems worked well to detect it in time, before launch, proving it is a robust launch vehicle. Prevention is better than loss and the decision to postpone the launch was correct. India has invested considerable time and resources on Chandrayaan-2 and we cannot take any chances in such a momentous mission," said Ratan Shrivastava, an Independent Aerospace & Defence consultant, ex Advisor, Space Division, Ficci and ex-Practice Director, Aerospace & Defence Consulting, Frost & Sullivan (Asia–Pacific). Meanwhile, social and mainstream media started discussions about the reliablity of GSLV MkIII, which will be used for India's Human Space Programme, nick named Gangayaan. The rocket is India’s most powerful launch vehicle, and can cary satellites weighing up to 4,000 kg to Geosynchronous Transfer Orbit (GTO) or about 10 tonnes to Low Earth Orbit (LEO), which is about twice the capability of current GSLV Mk II and more than thrice that of ISRO’s workhorse Polar Satellite Vehicle (PSLV). The rocket is a outcome of three decades of Isro's initiative, after India was denied cryogenic technology (science relating to the behaviour of materials at very low temperatures) in the early 1990s due to move by the United States. It is this cryogenic technology that led US to impose sanctions on India. GSLV Mk-III, which had an experimental flight in 2014, has till date has been used in only two launches -- GSAT-19 communication satellite in 2017 and GSAT-29 communication satellite in November 2018.

GSLV Mk-II, launched in March 2018, failed after Isro lost contact with its satellite, the GSAT-6A. While Isro was not responding, twitterati and experts came to the rescue, expressing faith in Isro with messages like "Better late than sorry". They said it (the call-off) was a good and brave decision on the parts of Isro scientists. "GSLV has already proven itself to be reliable. Such a hold-up in the automatic checkout systems of the launch sequence is routine in many other countries too. I don't think it is fair to conclude that GSLV is unpredictable just because the checkout systems detected an anomaly," said Narayan Prasad, co-founder of Satsearch, an European Space Agency-supported start-up. In order to buttress his point of diffrentiating between an aborted launch and failure, Prasad cited the example of the failed European Vega rocket launch on July 11. The rocket, carrying an imaging satellite for the United Arab Emirates, failed about two minutes after lift-off from the European base in French Guiana. Recently, Russia too had a failed launch and the cosmonauts had to make an emergency exit. "Detection of such anomalies before Gaganyaan and the ability to detect them and rectify them on time further proves the reliability of the vehicle design. These flights will further prove GSLV's record," Prasad asserted.

The Isro rocket scorecard

Of 48 launches by Polar Satellite Launch Vehicle (PSLV) only have failed.

* September 1993: PSLV-D1, IRS-1E Satellite could not be placed in orbit

* August 2017: PSLV-C39, carrying IRNSS-1H

PSLV is India's third-generation launch vehicle and the first to be equipped with liquid stages.

Out of 13 Geosynchronous Satellite Launch Vehicle (GSLV) launches, excluding Chandrayaan-2, three missions were unsuccessful.

* July 2006: GSLV-F02 carrying INSAT-4C

* April 2010: GSLV-D3 carrying GSAT-4

GSLV-F06 carrying GSAT-5P

(GSLV Mk II) is the largest launch vehicle developed by India, which is currently in operation. This fourth-generation, three-stage vehicle has four liquid strap-ons. The indigenously developed cryogenic Upper Stage (CUS), which is flight proven, forms the third stage of GSLV Mk II. The vehicle has achieved four consecutive successes since January 2014.

Isro last minute snags
  • In 2007 GSLV rocket, just 15 seconds before the lift-off, the rocket's computers put GSLV on hold detecting anomalies in the cryogenic fuel stage. The launch was postponed by two hours to set right the problem.
  • On August 19, 2013 GSLV-D5, carrying GSAT-14, was scheduled to launchedon August 19, 2013, but hours before the blast off the fuel started leaking from its second stage or engine later it was launched in January 2014
Global examples
  • In June 2014, Russia was forced to abandon debut launch of its first new space rocket since the Soviet era when the Angara booster cut out during a final countdown watched by President Vladimir Putin
  • In April 2016 unmanned Soyuz rocket was cancelled at last minute because a fault was uncovered with the rocket. They rescheduled for 24 hours later in March 2009, NASA has postopned the launch of the space shuttle discovery due to leakage in fuel system
  • In December 2007, NASA called off launch of space shuttle Atlantis due to fuel gauges issues
  • In July 2005, shuttle Discovery launch was cancelled two hours before its scheduled lift-off due to defective sensors on an external fuel tank

First Published: Mon, July 15 2019. 15:13 IST