Chandrayaan-2 countdown underway, Prez to bear witness

Over the moon

Amid unprecedented security at the Satish Dhawan Space Centre (SDSC) in Sriharikota, the Chandrayaan-2 mission took a decisive shift towards its Monday morning 2.51 am launch. At precisely 6.51 am on Sunday, the 20-hour countdown began clicking.

In no mood to take any chances on the country’s most ambitious lunar mission, the Indian Space Research Organisation (Isro), the Central and Andhra Pradesh State security forces have erected checkposts over 11 km ahead on the road leading to SDSC.

President Ram Nath Kovind will arrive later on Sunday night in Sriharikota to witness the launch, awaited globally with much anticipation. Dubbed ‘Baahubali,’ Isro’s most powerful rocket launcher GSLV Mk III will blast off with the Chandrayaan-2 mission components.

The public viewing gallery is a good 8-km away from the launch site, India’s only spaceport. “No one will be allowed anywhere close to the site for safety reasons. Even the Isro chairman cannot go beyond the 6-km periphery,” a space agency official explained.

As mediapersons from across the country and the world converged in Chennai for a midnight trip to Sriharikota, Isro prepared for potentially its most defining moment in history. The space agency reiterated that all checks on the rocket and the Mission components had been completed, and the launch was ready to go.

The ambitious Rs 1,000-crore Mission integrates an Orbiter, a 1.4-ton ‘Vikram’ Lander and a 27-kg ‘Pragyan’ Rover. The Lander is designed to touch down on the lunar South Pole, a feat none of the space-faring nations have achieved so far.

Moon-landing challenges

Isro chairman K Sivan is on record, articulating the challenges posed by the Moon-landing stage of Chandrayaan-2. He had said the lander, Vikram’s 15-minute descent would be “the most terrifying moments as we have never undertaken such a complex mission.”

Navigating large distances accurately, preventing damage due to ‘lunar’ dust, conducting Trans Lunar Injection and the soft-landing pose huge risks for Vikram. But if it succeeds, India will emerge as the fourth nation to accomplish the soft-landing mission after the United States, Russia and China.

Chandrayaan Payloads

The Orbiter is equipped with a terrain mapping camera that can generate extremely high definition imagery of the entire Moon. To relook at the presence of water, it also features a Synthetic Aperture Radar that will map the polar-region and confirm sub-surface water-ice.

Among the Vikram Lander’s payloads is an instrument to check lunar seismic activity around the landing site. Thermal conductivity experiments and temperature gradient trials are also part of the Lander’s tasks.

Once detached from Lander, the Pragyan Rover will roam around with its Alpha Particle X-Ray Spectrometer, studying the Moon’s elemental composition. A Laser Induced Breakdown Spectroscope is also part of the Rover’s payload.

Lunar Dust

The lunar surface is covered with craters, rocks and dust. Firing of onboard engines close to the lunar surface results in backward flow of hot gases along with dust. This dust is miniscule and is hard, barbed and jagged.

The dust’s negative charge makes it stick to most surfaces. This is bound to cause disruptions in deployment mechanisms, solar panel performance and sensor performance of the Rover and the Lander.

Extreme Temperatures and Vacuum

A lunar day or night lasts 14 Earth days. This results in extreme surface temperature variations. “Moreover, the ambient pressure of the lunar surface is a hard vacuum. This makes the surface an extremely hostile environment for lander and rover operations,” Isro officials say, citing the immense challenges posed by any attempt at Moon-landing.