ISRO gearing up for its second moon mission after successfully inserted an orbiter around the moon in 2008. This time ISRO dreamed to launch the more complex mission in July, the upcoming mission will comprise an orbiter, a lander and a rover. Isro described 7 major challenges in moon landing mission. Trajectory Accuracy, Deep space communication, Soft landing on the moon etc.
The launch window is from 9 to 16 July 2019.
The distance to the moon is roughly 3.844 lakh km. Ensuring trajectory accuracy while navigating such a large distance poses many challenges. Spacecraft trajectory is influenced by the non-uniform gravity of the earth and moon. Gravitation pull of other astronomical bodies, solar radiation pressure, and moon’s true orbital motion also affect spacecraft path.
Deep space communication
Owing to the large distance from Earth and limited onboard power, radio signals used for communication are a week. Background noise also mixes with them. So large antennas need to capture such small signals.
Trans Lunar Injection and Lunar Capture
Chandrayan 2 will perform a series of TLI burns for raising its apogee successfully to reach the vicinity of the Moon’s orbit. As the moon’s location is continuously changing due to orbital motion the intersection of chandaryan-2 and moon’s path has to be predicted sufficiently in advance with a high level of accuracy. As the Moon approaches chandaryan-2 onboard engine fired precisely to reduce its velocity for lunar capture.
The margin of error in these calculations and manoeuvres is very low. If we missed this, mission failed.
Orbiting around the moon
Lunar gravity is lumpy due to uneven mass distribution under its surface. This influences the orbit of the spacecraft. Also, Precise knowledge of thermal environment at orbital altitude is essential for keeping on-board electronic equipment safe.
Soft landing on the moon
This is the most challenging phase of the mission. It is divided into ‘rough trekking’ and fine braking. Variation in local gravity has to be factored into the lunar descent trajectory. The onboard NGC and the propulsion system have to work in unison, autonomously and automatically for a successful landing. Further, the landing site landscape features should result in a communication shadow area.
The lunar surface is covered with craters, rocks and dust. Firing of onboard engines close to the lunar surface results in backward flow of hot gases along with dust. Lunar dust is minuscule and hard, barbed and jagged. Its negative charge makes it stick to the most surface. Which cause a disruption in deployment mechanisms, solar panel performance and NGC sensor performance.
Extreme temperature and vaccum
A lunar day or night lasts 14 Earth days. This results in extreme surface temperature variations. Moreover, the ambient pressure of the lunar surface is a hard vacuum. This makes the lunar surface an extremely hostile environment for lander and rover operations.
View more about Chanderyan-2
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