Chandrayaan-2: Moon landing is challenging and tricky


Trilok Singh (YD's Blog): It is India's second mission to the Moon - Chandrayaan-2, which is set for launch from the spaceport of Sriharikota in Andhra Pradesh on July 15, at 2:51 a.m. by Indian Space Research Organisation (ISRO), and has legacy in Chandrayaan-1 as well. Notably, The Nation’s maiden unmanned moon mission which was announced by late Prime Minister Shri Atal Bihari Vajpayee on the 56th Independence Day in 2003. While announcing such mission, He had assumed that the Nation was “ready to fly high in the field of science”.

Chandrayaan-2 launch LIVE: ISRO’s 2nd space mission to Moon


Read Also, India’s moon mission was first announced in 2003

Although, The Chandrayaan-2 mission will be the most challenging and technologically complex because Indian Space Research Organisation (ISRO) will not only be putting the orbiter around the moon but also soft-landing the lander on lunar soil and deploying the rover, which will be driven around the moon’s surface. The lander, with the rover inside, after separating from the orbiter circling above the moon, will slowly descend and gently land on the South Pole of the moon, on September 6 or 7. So, It will take 53 to 54 days to travel the 3.84 lakh km from the earth to the moon’s surface.
From the blasting off of the India's heavy lift rocket, Geosynchronous Satellite Launch Vehicle - Mark III (GSLV-Mk III), from the rocket port in Sriharikota on July 15, till the Lander Vikram lands on the moon's surface on September 6, the challenges are many, ISRO asserted. 
Moon landing, the significant part of this mission, it is not like an aircraft taking off from one airport and landing in another. To began with, the about 3.844 lakh km distance between the earth and the moon. Hence, Ensuring trajectory accuracy while travelling such a long distance is a challenge as trajectory is influenced by the non-uniform gravity of the earth and the moon, gravitational pull of other astronomical bodies, solar radiation pressure and the moon's true orbital motion, According to a well sourced information here.
Following this, The another challenge is the deep space communication link between the Space Agency (ISRO) and the Chandrayaan-2. Owing to the distance, limited on-board power, radio signals will be weak with heavy background noise. The signals have to be picked up by large antennas. While on its way to the moon, the Chandrayaan-2 has to change route from the earth orbit to moon orbit. This will be done by firing on-board motors so that the Chandrayaan-2 is raised to reach the vicinity of the moon's orbit.

Read Also, NASA picks new teams to study Moon, asteroids

As per the experts, Since the moon's location changes continually owing to orbital motion, the intersection of Chandrayaan-2 and the moon's path has to be predicted in advance and accurately. The thrusters on-board the Chandrayaan-2 are fired precisely reducing the velocity for lunar capture. The margin of error in these calculations and manoeuvres is very narrow.

Highlighting the challenge of orbiting around the moon, The lunar gravity is lumpy owing to uneven mass distribution under its surface which in turn influences the spacecraft's orbit. Further precise knowledge of the thermal environment at orbital altitude is a must for keeping on-board electronics safe, ISRO asserted.
In the main part of this mission, soft landing of Vikram on the moon from Chandrayaan-2. While the landing process is divided into "rough braking" and "fine braking". The descent trajectory of Vikram has to take into account the variation in local gravity. Further the landing site, landscape features should not result in a communication shadow area.

The another challenge is the moon dust. The moon's surface is covered with craters, rocks and dust. Firing the onboard motors close to the surface will result in backward flow of hot gases and miniscule, hard/barbed/jagged dust. Its negative charge makes it stick to most surfaces, causing a disruption in deployment mechanisms, solar panel and sensor performance. Despite the same, the challenges is the extreme surface temperature variations as a lunar day or night lasts 14 earth days. Moreover, the ambient pressure of lunar surface is a hard vacuum. This makes the lunar surface an extremely hostile environment for lander and rover operations, ISRO asserted.
Meanwhile, K. Sivan, ISRO Chairman, remarked that the 15 minutes from the separation from the orbiter to the soft-landing “will be the most terrifying moments”. “These 15 minutes will form the most complex mission that ISRO has ever undertaken. The throttleable engines are a new (technology) development for us.” While Former ISRO Chairman A.S. Kiran Kumar stated with regard to the progress of space observation and how the scientific payloads onboard, Chandrayaan 2 will help us better understand the Moon.

Despite all of this, ISRO on its official website explains that, "Extensive mapping of lunar surface to study variations in lunar surface composition is essential to trace back the origin and evolution of the Moon. Evidence for water molecules discovered by Chandrayaan-1, requires further studies on the extent of water molecule distribution on the surface". All the best ISRO for Mission Chandrayaan-2.

Jai Hind.

(It is well documented with Agency inputs on Youth Darpan and IASmind.com: For any corrections, kindly mail us at trilok@youthdarpan.com).

Author: (Trilok Singh, CEO at Youth Darpan Media, IASmind.com & India's Journal. Currently Studies Master's Degree in Journalism at International School of Media and Entertainment Studies (ISOMES), News 24. MA in Political Science from Kirori Mal College, DU.