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Chandrayaan-2: Fault rectified, ISRO reschedules launch for July 22

New Delhi: The Indian space agency on Thursday announced that the Chandrayaan-2 launch has been rescheduled for July 22, seven days after the ambitious launch by ISRO had to be aborted an hour before the lift off.

“Chandrayaan-2 launch, which was called off due to a technical snag on July 15, 2019, is now rescheduled at 2.43 p.m. IST on Monday, July 22, 2019,” the Indian Space Research Organisation tweeted.

This comes after ISRO rectified the fault in its Geosynchronous Satellite Launch Vehicle-Mark III (GSLV-Mk III) whose Monday flight with Chandrayaan-2 spacecraft was called off one hour before its lift off.

The rocket GSLV-Mk III was supposed to lift off at 2.51 a.m. on Monday with India’s second moon mission spacecraft Chandrayaan-2.

One hour before the lift-off officials detected a snag and called off the mission.

“A technical snag was observed in launch vehicle system at 1 hour before the launch. As a measure of abundant precaution, #Chandrayaan2 launch has been called off for today. Revised launch date will be announced later,” ISRO had then tweeted without elaborating further.

It is said non-building of sufficient pressure in the helium tanks of the GSLV-Mark III rocket forced the cancellation of the launch on Monday.

The ISRO has decided to go ahead with the launch at the next best available date even if conditions are not totally perfect.

The rocket Geosynchronous Satellite Launch Vehicle-Mark III (GSLV-Mk III) was supposed to lift off at 2:51am on Monday, July 15, with India’s second moon mission spacecraft Chandrayaan-2. If the launch had taken place according to plan, the lander from Chandrayaan would have landed on the moon’s surface after 54 days, on September 6.

The ISRO is currently, trying to ensure that the rocket reaches the moon on the same date by adjusting the speed and orbiting path of the rocket. The rocket will take at least 22 days to circle Earth’s orbit and move on the Moon’s orbit. The agency has shortened the next 28 day duration taken by the spacecraft to reach the Moon’s surface.

Sources reveal that the ISRO scientists were able to fix the issue without dismantling the rocket or shedding the fuel.

According to the retired officials of ISRO there should be proper pressure in the liquid fuel tanks so that there is continuous flow of fuel to the combustion chamber.

“While the fuel is fed into the combustion chamber from the bottom, helium gas is filled from the top. It seems sufficient pressure was not being built up and hence the launch was called off,” a retired ISRO official informed.

According to him, the flow of fuel to the combustion chamber should be uniform for the rocket to fly.

In 2006, the GSLV-F02 (different variant of GSLV) went out of control less than a minute after lift-off and had to be destroyed in air after it started breaking up.

The reason for the failure, an expert committee in its failure analysis report said, was that a propellant regulator in one of the four strap-on liquid motors had much higher discharge coefficient in its closed condition.

At that time ISRO ruled out any sabotage theories and said the quality checks and inspections has been strengthened.

Incidentally, even the very first flight of GSLV slated for March 28, 2001, was automatically aborted seconds before the lift-off.

That launch was aborted with the automatic shutdown of the main engine just a second before the lift off.

That too after the four liquid propulsion strap-on boosters started burning.

The automatic shut off system was activated when it sensed that one of the strap-on boosters did not develop the required thrust. The vehicle was immediately disarmed.

The rocket was later flown on January 18, 2001, carrying GSAT-1 satellite.


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