Milestones Series- Chandrayaan 2 | Gist of Rajya Sabha TV / RSTV (now Sansad TV) - UPSC PDF Download

Introduction

Chandrayaan-2 mission is a highly complex mission, which represents a significant technological leap compared to the previous missions of ISRO, which brought together an Orbiter, Lander and Rover with the goal of exploring the south pole of the Moon. This is a unique mission which aims at studying not just one area of the Moon but all the areas combining the exosphere, the surface as well as the sub-surface of the moon in a single mission.

Chandrayaan-2 mission

• In September 2008, the Chandrayaan-2 mission was approved by the government for a cost of Rs 425 crore.
• It is India’s second mission to the moon.
• It aims to explore the Moon’s south polar region.
• It was launched onboard India’s most powerful launcher – GSLV MK-III.
• The mission is an important step in India’s plans for planetary exploration, a program known as Planetary Science and Exploration (PLANEX).
• There are three components of the mission, an orbiter, a lander and a rover.
• The orbiter is deployed at an altitude of 100 kilometers above the surface of the Moon.The lander is separated from the orbiter, and execute a soft landing(but could not is what is said) on the surface of the Moon, unlike the previous mission which crash landed near the lunar south pole.
• The lander, rover and orbiter will perform mineralogical and elemental studies of the lunar surface. The rover is named Pragyan.
• The mission’s lander is named Vikram after Dr Vikram A Sarabhai, the Father of the Indian Space Programme.
• If ISRO achieves the feat in its first attempt, it will make India only the fourth country to soft-land on the lunar surface. The erstwhile Soviet Union, the U.S. and China are the only countries to have achieved lunar landings.

Soft landing:

• A soft-landing protects the object from impact while a hard landing doesn’t.
• Soft-landing ensures that the object is able to carry out further experimentation on the target planet or satellite, mostly with the help of a rover vehicle.
• Soft-landing on any planetary surface is complicated. Vikram was to use five thrusters — four at the corners and one at the centre to make its final descent.
• Maintaining the required velocity with such thrusters is difficult as a fine balance among them needs to be maintained.
• Then there is the issue of moon dust which could wreck the engines of the thrusters.

GSLV Mk-III:

• Developed by ISRO, the Geosynchronous Satellite Launch Vehicle Mark-IIIis a three-stage vehicle.
• Primarily designed to launch communication satellites into geostationary orbit.
• It has a mass of 640 tonnes that can accommodate up to 8,000 kg payload to LEO and 4000 kg payload to GTO.
• GSLV Mk-III vehicle is powered by two solid motor strap-ons (S200), a liquid propellant core stage (L110) and a cryogenic stage (C25),that has been designed for carrying the four-tonne class satellites.
• The C25 is powered by CE-20, India’s largest cryogenic engine, designed and developed by the Liquid Propulsion Systems Centre

Chandrayaan-2 to have 3 components — Orbiter, Lander and Rover:

• Chandrayaan 2is India’s second lunar mission with three modules: the Orbiter, Lander (Vikram) and Rover (Pragyan).
• The Orbiter and Lander are mechanically interfaced and stacked together as an integrated moduleinside the launch vehicle, GSLV MK-III.
• Rover is housed inside Lander.
• After the launch into an earth-bound orbit by GSLV MK-III, the integrated module reached the moon orbit using the orbiter propulsion module.
• Chandrayaan spacecraft, with a mass of 3.8 tonne, has three modulescomprising of the Orbiter, Lander (Vikram) and Rover (Pragyan).

Lander (Vikram):

• This was first time that ISRO is attempting to soft-land a modulein extra-terrestrial Space.
• Once the Lander and Rover, enter the Moon’s gravity, they would be in a state of free fall.That could end up in crash-landing and destruction of instrument.
• To enable a smooth landing, the speed of the Lander just ahead of touchdown should be 6 kilometres per hour or less.

Rover (Pragyan):

• The Rover, a six-wheeled solar-powered vehicle, will detach itself and slowly crawl on the surface, making observations and collecting data.
• It will be equipped with two instruments, the primary objective is to study the composition of the surfacenear the lunar landing site, and determine its abundance of various elements.

What the Orbiter will do?

• Terrain Mapping camera 2 will map lunar surface
• Look for presence of major elementson the moon
• Atmospheric compositional explorer 2 will study composition of lunar neutral exosphere.

Chandrayaan 2: The positives

• Successful initiation of operational service of GSLV MK III
• GSLV MK III has carrying capacity of 4000 kgs; can be commercialized.
• Precise placement into orbit saved fuel, giving orbiter prolonged life around moon.
• Orbiter earlier predicted to have one year life span could now go on for 7.5 years.
• Will generate 3D terrain map, study mineral distribution.
• Orbiter has already sent images.
• Data generated by such missions yield results for long time.
• Vikram got extremely close (i.e 2.1 kms) to realizing soft landing, providing many lessons.