CHENNAI: As the country is preparing to launch its most complex space mission - Chandrayaan-2 - early next month, space scientists will be faced with several challenges on the road to scripting history.
If successful, Chandrayaan-2 will make India the fourth country in the world to soft-land on the moon.
ISRO on Monday said that there are seven things that would determine the mission’s success or failure. Here is the explainer:
Soft landing on the Moon
This is the most challenging part of the mission and is divided into ‘rough braking’ and ‘fine braking’. Variations in local gravity have to be factored into the lunar descent trajectory. On-board Navigation and Control and propulsion system has to work in unison, autonomously and automatically.
Trajectory accuracy
The distance to the moon is approximately 3.844 lakh km. Ensuring trajectory accuracy while navigating such a large distance poses many challenges as it is influenced by non-uniform gravity of the Earth and Moon, etc..
Deep-space communication
Owing to the large distance from Earth and limited on-board power, radio signals used for communication are weak with heavy background noise, which need to be picked up by large antennas.
TLI and Lunar Capture
Chandrayaan-2 will perform Trans Lunar Injection (TLI) burns for raising its apogee successively to reach vicinity of Moon’s orbit. As the Moon’s location continuously change due to orbital motion, the intersection of Chandrayaan-2 and the Moon’s path must be predicted accurately.
Orbiting around the Moon
Lunar gravity is ‘lumpy’ due to uneven mass distribution under its surface. This influences the spacecraft obit. Also, precise details of thermal environment at orbital altitude is needed for keeping electronics safe.
Lunar dust
Lunar surface is covered with craters, rocks, and dust. Firing of on-board engines close to the lunar surface results in backward flow of hot gases along with dust.
The negative charge of lunar dust makes it stick to most surfaces disrupting deployment mechanisms, solar panel performance and NGC sensor performance.
Extreme temperature, vacuum
A lunar day or night lasts 14 Earth days. This results in extreme surface temperature variations. Moreover, the ambient pressure of the surface is a hard vacuum. This makes the lunar surface an extremely hostile environment for lander and rover operations.