How ISRO’s Chandrayaan-2 Will Go To The Moon


In 2008, India made its first big leap into space as Chandrayaan-1 set out for the Moon.

The Indian spacecraft orbited the Moon and beamed back evidence of water on the lunar surface, and below it, and, in the process, gave life to new geological curiosities.

But, 10 months into its two-year-long mission, it fell silent, bringing the exploration to an end. ISRO chairman G Madhavan Nair had then claimed that the mission had achieved 95 per cent of its objectives, later revising it to 110.

Now, ten years later, India gears up to return to the Moon. Only this time, it will set foot on the lunar surface—on the Moon’s apparently water-rich but freezing-cold south pole. According to reports, this region is an entirely unexplored territory and, therefore, presents a great opportunity to discover the presence of water on the Moon.

The landing site is also known to have ancient rocks that would offer clues on the history of the Moon and fossil records of the early solar system.

Chandrayaan-2 will essentially comprise three modules - an orbiter, a lander named ‘Vikram’, and a rover named ‘Pragyan’.

The mission will take off on board ISRO’s GSLV Mark III at 2.51 am on 15 July. The lander and the rover will be seated inside the launch vehicle.

The take-off will begin with the ignition of the two solid strap-on boosters. The rocket will slowly pick up momentum and be thrust into space.

Then, the second stage will kick in, as the liquid-fueled core, powered by a pair of Vikas engines, will fire up, and the strap-on boosters will be released.

Next, the covering to protect the payload will strip away as the rocket pushes through the Earth’s atmosphere.

After this, the liquid core stage will shut down and get detached, and the cryogenic upper stage, powered by India's largest cryogenic engine, will ignite, driving the module into a highly elliptical orbit.

At this stage, the propulsion system on board will raise the module’s orbit around the Earth through a series of burns. The module will experience a variation in speed as it undulates between points that are farthest and nearest to Earth.

Every time the module reaches the perigee, or the point of the highest speed, the onboard engine will fire up, raising the speed even more, pushing it into a higher, more elongated orbit. With every burn of the onboard propulsion system, the module will keep spiralling outwards in increasingly elongated ellipses.

Eventually, the module’s speed will reach the escape velocity required to escape Earth’s gravity, and its orbit, elongated enough for it to set a course for the Moon, till it eventually gets close - and then, into a lunar orbit.

Nearly one and a half months after setting out for the Moon, Chandrayaan-2 will orbit Earth's satellite.

And then comes the tricky part. Here, the lander will separate from the orbiter and begin its descent towards the lunar surface. Once it gets to a level around 18 kilometers from the surface, a detection camera and hazard avoidance sensor will evaluate the landing site. From the data obtained, the lander will make its way to the predetermined landing site, reaching 100 meters above it.

The lander will then be guided to the safest landing point and, at the height of 2 meters, the thrust will be cut off, and the lander will go into free fall towards the impact point, with the legs absorbing the impact shock on landing.

Then, the six-wheel rover, Pragyan, will get into action. It will operate for 14-15 Earth days, or one lunar day, with ISRO exercising partial control from Earth. The orbiter, meanwhile, will continue to go around the Moon and will do so for a year.

And that, in a nutshell, will be India’s Chandrayaan-2 mission - one that will expand India’s footprint in space science and hopefully sow the seeds of future scientific discovery.

There used to be this space race back in the day when the US and the USSR used to try and outgun each other in the area of space research, defence, and exploration. This race has now emerged in a new avatar - a 2.0 version if you like - where space agencies, both government and private, are gunning for superiority. It’s here that ISRO is shining, thanks to spectacular feats like launching 104 satellites in one launch and for its almost unthinkable frugality.

With Chandrayaan-2, India has an opportunity to leave a mark, a much bigger one, on the space stage - and if it manages to pull it off, that will be another feather in its cap, but it will also be a critical stepping stone to greater success in the future.

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