One small step for ISRO…

Lunar Odyssey: Chandrayaan-2 is part of a series that should one day land an Indian on the moon

Moon

At about 2.51am on July 15, a rocket will blast off from the Sriharikota spaceport on India’s most ambitious and complex space mission yet – Chandrayaan-2. It will be exactly 50 years – almost to the day – since the ‘Eagle’ landed on the moon and Neil Armstrong stepped out hours later onto lunar soil and proclaimed that he had taken “one small step for man, a giant leap for mankind.” The Apollo 11 mission on which he embarked, along with ‘Buzz’ Aldrin and Michael Collins, was launched on July 16, 1969, and the ‘Eagle’ landed on the moon four days later on July 20. That was, of course, a qualitatively different mission – being the first time ever that humans landed on the moon – but Chandrayaan-2 is India’s “small step” for now. Eventually, a future Chandrayaan mission could well be our “giant leap.”

Chandrayaan-2 follows Chandrayaan-1, which was launched in October 2008, India’s first moon shot. Chandrayaan-1 was an orbiter spacecraft that went round the moon on an orbit 100 km above the earth’s only satellite. The only thing that touched the moon then was a small but very significant ‘impactor’ that crashed onto lunar surface. This time, though, Chandrayaan-2 carries in its belly a lunar lander and a rover. The mission is to land the lander and rover gently onto the moon, while the spacecraft remains in orbit.

Appropriately, the Indian Space Research Organisation (Isro) has called the lander ‘Vikram’ – after Vikram Sarabhai, the ‘father of the Indian space programme’. Isro was initially founded under the Department of Atomic Energy with the cosmic ray scientist and the first prime minister Jawaharlal Nehru’s confidant on all matters science, Homi Bhabha, heading both endeavours. Following Bhabha’s death in a plane crash in January 1966, Indira Gandhi made his chosen successor Vikram Sarabhai the head of the space agency.

Through Sarabhai and his successors, Isro has developed from a space agency that was focused on societal transformation – developing and launching satellites for weather, agriculture, education and similar applications – to one that now boasts full-spectrum  capabilities of a space agency that’s raring to go into planetary exploration, space astronomy, military space applications and more. Chandrayaan-1, conceived in 1999 and launched in 2008, was the beginning of this new avatar of Isro in a rising India. It was followed by the Mars Orbiter Mission in 2013.

Chandrayaan-2, coming almost 11 years after the first moon shot, was initially planned as a joint Indo-Russian mission, with Russia bringing in the lander and rover. Thankfully, though, Russia pulled out of the mission after it was unable to build the lander and rover in time. Isro had to go it alone. It did, in the process developing the capability to build a lander that can land softly on the lunar surface, a rover that will trundle – albeit very slowly – on the lunar surface, and the algorithms, new communication capabilities and high-tech materials needed to make all this function smoothly.  

Getting to the Moon

While the world prepares for the 50th anniversary of the Apollo 11 moon landing, a Geosynchronous Satellite Launch Vehicle (GSLV) Mk III M1 rocket – India’s most powerful launch vehicle to date – will lift off from Sriharikota’s Satish Dhawan Space Centre (named for Sarabhai’s successor at Isro, Prof. Satish Dhawan), carrying its nearly 3.8-tonne payload – the Chandrayaan-2 spacecraft (2,379 kg), the Vikram lander (1,371 kg) and the Pragyan rover (only 27 kg). Together, the three carry 14 scientific payloads. The cost of going to the moon with all this: Rs 978 crore (Rs 375 crore for the launch, Rs 603 crore for the rest).

If it succeeds, India will become the fourth country – after the US, Russia and China – to achieve safe landing on the moon and to operate a rover on its surface. Only in April, Israel’s bid to land safely on the moon failed when its Beresheet-1 crashed onto the lunar surface and was destroyed.

Manoeuvring in Orbit

The GSLV will launch Chandrayaan-2 into an Earth Parking Orbit, where it will spend some 16 days orbiting the earth. During this time, Isro will perform ‘orbit-raising’ manoeuvres, firing the spacecraft’s small rockets to push it up into higher orbits and eventually into a trajectory that puts it on its way to its destination: the moon.

Five days later, Chandrayaan-2 will coast into orbit around the moon – some 3,80,000 kilometres away!

There, it will spend 27 days around the moon, getting into an appropriate orbit. When it gets there, the lander will separate from the orbiter. Vikram, holding Pragyan in its belly, will first sit on top of the spacecraft and then be released to jump off it. It will hurtle down towards the moon. At about 30 km from the surface, Vikram will begin the careful descent onto the surface.  

“The 15-minute operation, in which Vikram makes the final descent and soft-lands, will be the most terrifying as we have never attempted such a complex mission,” Isro chairman K Sivan told reporters on June 11.

Technically, Sivan’s and Isro’s worry is compounded by another challenge that they have taken upon themselves: Chandrayaan-2 will land on the moon’s south pole – a first in lunar exploration.  

Fifty years ago, it was the same harrowing experience -- magnified many times over because human lives were at stake -- for all involved in the Apollo 11 mission. Some things in space exploration never change!

If all goes well, on September 6, Vikram will gently touch down on the moon. Four hours later, its door will open and slowly, Pragyan the rover will wheel out onto moon’s surface. How slowly? “Rover will move at a speed of 1 centimetre per second”, according to Sivan. “It will travel 500 metres on the moon’s surface during its life.”   

The solar-powered Vikram and Pragyan are both designed for a lifespan of one lunar day – or 14 earth days. The orbiter, on the other hand, will last a year.

Between the orbiter, lander and rover, the Chandrayaan-2 mission carries 14 payloads for experiments and measurements – 13 of them Indian, one from NASA. They include eight remote-observation payloads on the orbiter, three on the lander and two on the rover. Isro hopes to map the craters in the polar region, analyse the chemical composition of lunar soil and rocks, advance the work done by Chandrayaan-1 on water on the moon, and scout for potential landing sites for future missions, including manned ones.

Not alone

Chandrayaan-2 won’t be alone on and around the moon. India’s Vikram and Pragyan will have the company of China’s Chang’E-4 – on the far side of the moon! Its lander and Yutu 2 rover arrived there on January 3, 2019.

Isro is about to embark on its most nerve-wracking space mission yet. If you are a believer, pray for it and for India. If you are a non-believer, wonder about what humans are capable of and dream of an Indian on the moon soon!  

Comments (+)