After India’s second moon mission, Chandrayaan-2, was called off on 15 July, with the Indian Space Research Organisation (ISRO) claiming that it would now be launched on 22 July, it’s been revealed that the ‘technical snag’ that caused the delay was due to a pressure drop in one of the helium tanks.
According to a report in the Indian Express, an ISRO scientist associated with the mission said:
“The pressure in one of the helium tanks was observed to be falling. It happened while the cryogenic fuel, which is supercooled to temperatures well below -100 degrees Celsius, was being loaded. Because of the extremely low temperatures of the fuel, the environment surrounding the fuel tanks also get cooled.”
The scientist further said, as quoted by the Indian Express, that, “This helium tank was in close proximity to the fuel tank. So, the pressure drop could be because of the loading of the fuel. A filled up balloon, if put on ice, would deflate. Something similar could have happened here as well. But at that time, scientists were not able to ascertain whether it was because of the fuel loading or because of a leak in the helium chamber.”
Last week, after the delay of the launch of the GSLV launch vehicle, ISRO had not provided an official reason for postponing the launch, although reports were rife with speculation that it might have been due to a leak in the helium bottle of the cryogenic engine of the GSLV Mk-III rocket.
The ISRO scientist further told IE that the problem “was not fatal”.
“It was not something that could have prevented the mission from lifting off. The mission could have been successful as well. But this would have entailed taking a risk. And mission control, in its judgment, decided that it was a risk not worth taking.”ISRO scientist, quoted by the Indian Express
The Launch Window
ISRO on Thursday, 18 July, announced that the country’s second moon mission, Chandrayaan-2 would be launched at 2:43 am on Monday, 22 July.
The space agency’s announcement had put an end to speculation about the launch. Some had been saying that it would be delayed till the next launch window, which will occur in September.
(A launch window, in this context is enough time to ensure a full 14 Earth days for the lander and the rover on the moon.)
The current launch window, according to ISRO, lasts till 31 July. The decided-upon date, 22 July, falls under this launch window.
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