Chandrayaan 2
The launch of Chandrayaan-2 launch was called off due technical snag on July 15, 2019.IANS/ISRO

New details explaining why the ambitious space mission, Chandrayaan 2, was halted an hour before its scheduled launch emerged on Tuesday, July 16.

Pressure drop in the fuel tank had caused an anomaly in the reading, an ISRO official said. "In order to maintain the temperature of liquid hydrogen at -253 degree centigrade, the upper stage of the rocket has nine helium tanks maintained at a pressure of around 300 PSI (pound per square inch). Pressure dropped by 10% in one of these tanks," reported The Economic Times.

While it was claimed that the issue was "not a big problem" and ISRO "would have gone ahead with the launch for most missions," the significance of the moon mission was cited as the reason behind ISRO's decision to abort the launch.

Ravi Gupta, the Directorate of Public Interface at Defence Research and Development Organisation (DRDO), told ANI that the decision to call off the launch was imperative. "We could not have taken any chance in such a big mission. Several rounds of testing are performed of every part. Every movement needs to be monitored at every second," he said.

The cost of the mission was also a factor that was extensively considered. Former Director of the Institute for Defence Studies and Analyses (IDSA) G Balachandran told ANI, "It's normal. If there are anomalies, you just can't send it off. Mission cost is over Rs 1,000 crore. It may be a simple thing or complex thing, they'll analyse it."

At Rs 978 crore, the lunar mission is one of the most cost-efficient space projects in the world. ISRO's budget for the mission is claimed to be 20 times less than its counterpart NASA.

The next launch date will be announced after 10 days following a thorough investigation.

On Monday evening, a NOTAM (notice to airmen), the mandatory alert issued ahead of every launch, said July 17, between 2:30 am and 3:30 am, and from July 18 to 31 between 2 pm and 3:30 pm, were identified as suitable windows for the next launch.

While no official confirmed dates are revealed, ISRO could use the one-minute window that will be available on July 22 to "implement corrective action" to rectify the glitch.

A successful launch would make India the fourth county in the world to soft-land a spacecraft and access the lunar surface. Only three countries - the US, Russia and China - have achieved the feat till now.  

The recent lunar mission follows the success of Chandrayaan 1, India's first expedition to the moon which confirmed landmark discoveries such as the presence of water on the moon. Chandrayaan 2 was designed to explore the dark side of the moon that faces away from the earth and was scheduled to spend 14 Earth days on the lunar surface.

On Monday morning, ISRO tweeted that the launch was aborted due to technical anomalies. It also called the move a "measure of abundant precaution."