Chandrayaan-3 vs. Chandrayaan-2: A Comparison of India's Moon Missions

Tags: Science and Technology

Why in News?

India’s third mission to the moon - Chandrayaan-3 - will take off on 14th July, 2023. The mission aims to achieve what its predecessor - Chandrayaan-2 could not - land softly on the lunar surface and explore it with a rover. A last-minute glitch led to the failure of the lander's (Vikram) soft landing attempt after a successful orbital insertion.

About The Chandrayaan-3 Mission:

• Chandrayaan-3 ("mooncraft") is a planned 3rd lunar exploration mission by the ISRO to demonstrate end-to-end capability in safe landing (through the lander Vikram) and roving (through the rover Pragyan) on the lunar surface. 

• Unlike Chandrayaan-2, it will not have an orbiter, and its propulsion module will behave like a communications relay satellite.

Comparing Chandrayaan 2 and 3 Missions:

• Chandrayaan-2 and Chandrayaan-3 have similar objectives of landing on the moon and exploring its surface with a rover. 

• However, there are several changes and improvements in the mission design of Chandrayaan-3 based on the lessons learned from Chandrayaan-2's failure.

Changes in the Mission Design:

• Expanded Landing Area: Chandrayaan-3 has been given instructions to land safely anywhere in a 4kmx2.4km area, unlike the specific 500mx500m patch targeted by Chandrayaan-2.

• Increased Fuel Capacity: The lander in Chandrayaan-3 has been provided with more fuel to travel longer distances to the landing site or an alternate landing site.

• Enhanced Landing Site Determination: Instead of relying solely on pictures taken during descent, high-resolution images from Chandrayaan-2's orbiter have been used to feed the lander with location information.

• Modified Lander Structure: Changes have been made to the lander's physical structure, including the removal of one thruster, strengthening of the legs for higher velocity landings, and the addition of more solar panels.

Chandrayaan-3 Payloads:

• Propulsion Module: It carries the Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload to search for smaller habitable planets.

• Lander Payloads: Chandrayaan-3's lander carries four payloads - Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA), Chandra’s Surface Thermophysical Experiment (ChaSTE), Instrument for Lunar Seismic Activity (ILSA), and Langmuir Probe (LP).

• Rover Payloads: The rover, Pragyan, is equipped with the Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscopy (LIBS) for analysing the elemental composition near the landing site.

How will the Mission be Implemented?

• The mission will be implemented by launching the lander-rover configuration into a 100-km lunar orbit using a propulsion module. 

• Once safely on the moon, the lander module (Vikram) will deploy the rover (Pragyan) to perform in-situ chemical analysis of the lunar surface.

Different Kinds of Moon Missions that have been Launched so far:

• Moon missions can be categorized into flybys, orbiters, impact missions, landers, rovers, and human missions. 

• Chandrayaan-3 falls under the landers and rovers category, aiming for a soft landing and mobile exploration on the lunar surface.